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Systematic Review | Definition, Example, & Guide

Systematic Review | Definition, Example & Guide

Published on June 15, 2022 by Shaun Turney . Revised on November 20, 2023.

A systematic review is a type of review that uses repeatable methods to find, select, and synthesize all available evidence. It answers a clearly formulated research question and explicitly states the methods used to arrive at the answer.

They answered the question “What is the effectiveness of probiotics in reducing eczema symptoms and improving quality of life in patients with eczema?”

In this context, a probiotic is a health product that contains live microorganisms and is taken by mouth. Eczema is a common skin condition that causes red, itchy skin.

What is a systematic review, systematic review vs. meta-analysis, systematic review vs. literature review, systematic review vs. scoping review, when to conduct a systematic review, pros and cons of systematic reviews, step-by-step example of a systematic review, other interesting articles, frequently asked questions about systematic reviews.

A review is an overview of the research that’s already been completed on a topic.

What makes a systematic review different from other types of reviews is that the research methods are designed to reduce bias . The methods are repeatable, and the approach is formal and systematic:

Formulate a research question
Develop a protocol
Search for all relevant studies
Apply the selection criteria
Extract the data
Synthesize the data
Write and publish a report

Although multiple sets of guidelines exist, the Cochrane Handbook for Systematic Reviews is among the most widely used. It provides detailed guidelines on how to complete each step of the systematic review process.

Systematic reviews are most commonly used in medical and public health research, but they can also be found in other disciplines.

Systematic reviews typically answer their research question by synthesizing all available evidence and evaluating the quality of the evidence. Synthesizing means bringing together different information to tell a single, cohesive story. The synthesis can be narrative ( qualitative ), quantitative , or both.

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what is the purpose of a systematic literature review

Systematic reviews often quantitatively synthesize the evidence using a meta-analysis . A meta-analysis is a statistical analysis, not a type of review.

A meta-analysis is a technique to synthesize results from multiple studies. It’s a statistical analysis that combines the results of two or more studies, usually to estimate an effect size .

A literature review is a type of review that uses a less systematic and formal approach than a systematic review. Typically, an expert in a topic will qualitatively summarize and evaluate previous work, without using a formal, explicit method.

Although literature reviews are often less time-consuming and can be insightful or helpful, they have a higher risk of bias and are less transparent than systematic reviews.

Similar to a systematic review, a scoping review is a type of review that tries to minimize bias by using transparent and repeatable methods.

However, a scoping review isn’t a type of systematic review. The most important difference is the goal: rather than answering a specific question, a scoping review explores a topic. The researcher tries to identify the main concepts, theories, and evidence, as well as gaps in the current research.

Sometimes scoping reviews are an exploratory preparation step for a systematic review, and sometimes they are a standalone project.

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A systematic review is a good choice of review if you want to answer a question about the effectiveness of an intervention , such as a medical treatment.

To conduct a systematic review, you’ll need the following:

A precise question , usually about the effectiveness of an intervention. The question needs to be about a topic that’s previously been studied by multiple researchers. If there’s no previous research, there’s nothing to review.
If you’re doing a systematic review on your own (e.g., for a research paper or thesis ), you should take appropriate measures to ensure the validity and reliability of your research.
Access to databases and journal archives. Often, your educational institution provides you with access.
Time. A professional systematic review is a time-consuming process: it will take the lead author about six months of full-time work. If you’re a student, you should narrow the scope of your systematic review and stick to a tight schedule.
Bibliographic, word-processing, spreadsheet, and statistical software . For example, you could use EndNote, Microsoft Word, Excel, and SPSS.

A systematic review has many pros .

They minimize research bias by considering all available evidence and evaluating each study for bias.
Their methods are transparent , so they can be scrutinized by others.
They’re thorough : they summarize all available evidence.
They can be replicated and updated by others.

Systematic reviews also have a few cons .

They’re time-consuming .
They’re narrow in scope : they only answer the precise research question.

The 7 steps for conducting a systematic review are explained with an example.

Step 1: Formulate a research question

Formulating the research question is probably the most important step of a systematic review. A clear research question will:

Allow you to more effectively communicate your research to other researchers and practitioners
Guide your decisions as you plan and conduct your systematic review

A good research question for a systematic review has four components, which you can remember with the acronym PICO :

Population(s) or problem(s)
Intervention(s)
Comparison(s)

You can rearrange these four components to write your research question:

What is the effectiveness of I versus C for O in P ?

Sometimes, you may want to include a fifth component, the type of study design . In this case, the acronym is PICOT .

Type of study design(s)
The population of patients with eczema
The intervention of probiotics
In comparison to no treatment, placebo , or non-probiotic treatment
The outcome of changes in participant-, parent-, and doctor-rated symptoms of eczema and quality of life
Randomized control trials, a type of study design

Their research question was:

What is the effectiveness of probiotics versus no treatment, a placebo, or a non-probiotic treatment for reducing eczema symptoms and improving quality of life in patients with eczema?

Step 2: Develop a protocol

A protocol is a document that contains your research plan for the systematic review. This is an important step because having a plan allows you to work more efficiently and reduces bias.

Your protocol should include the following components:

Background information : Provide the context of the research question, including why it’s important.
Research objective (s) : Rephrase your research question as an objective.
Selection criteria: State how you’ll decide which studies to include or exclude from your review.
Search strategy: Discuss your plan for finding studies.
Analysis: Explain what information you’ll collect from the studies and how you’ll synthesize the data.

If you’re a professional seeking to publish your review, it’s a good idea to bring together an advisory committee . This is a group of about six people who have experience in the topic you’re researching. They can help you make decisions about your protocol.

It’s highly recommended to register your protocol. Registering your protocol means submitting it to a database such as PROSPERO or ClinicalTrials.gov .

Step 3: Search for all relevant studies

Searching for relevant studies is the most time-consuming step of a systematic review.

To reduce bias, it’s important to search for relevant studies very thoroughly. Your strategy will depend on your field and your research question, but sources generally fall into these four categories:

Databases: Search multiple databases of peer-reviewed literature, such as PubMed or Scopus . Think carefully about how to phrase your search terms and include multiple synonyms of each word. Use Boolean operators if relevant.
Handsearching: In addition to searching the primary sources using databases, you’ll also need to search manually. One strategy is to scan relevant journals or conference proceedings. Another strategy is to scan the reference lists of relevant studies.
Gray literature: Gray literature includes documents produced by governments, universities, and other institutions that aren’t published by traditional publishers. Graduate student theses are an important type of gray literature, which you can search using the Networked Digital Library of Theses and Dissertations (NDLTD) . In medicine, clinical trial registries are another important type of gray literature.
Experts: Contact experts in the field to ask if they have unpublished studies that should be included in your review.

At this stage of your review, you won’t read the articles yet. Simply save any potentially relevant citations using bibliographic software, such as Scribbr’s APA or MLA Generator .

Databases: EMBASE, PsycINFO, AMED, LILACS, and ISI Web of Science
Handsearch: Conference proceedings and reference lists of articles
Gray literature: The Cochrane Library, the metaRegister of Controlled Trials, and the Ongoing Skin Trials Register
Experts: Authors of unpublished registered trials, pharmaceutical companies, and manufacturers of probiotics

Step 4: Apply the selection criteria

Applying the selection criteria is a three-person job. Two of you will independently read the studies and decide which to include in your review based on the selection criteria you established in your protocol . The third person’s job is to break any ties.

To increase inter-rater reliability , ensure that everyone thoroughly understands the selection criteria before you begin.

If you’re writing a systematic review as a student for an assignment, you might not have a team. In this case, you’ll have to apply the selection criteria on your own; you can mention this as a limitation in your paper’s discussion.

You should apply the selection criteria in two phases:

Based on the titles and abstracts : Decide whether each article potentially meets the selection criteria based on the information provided in the abstracts.
Based on the full texts: Download the articles that weren’t excluded during the first phase. If an article isn’t available online or through your library, you may need to contact the authors to ask for a copy. Read the articles and decide which articles meet the selection criteria.

It’s very important to keep a meticulous record of why you included or excluded each article. When the selection process is complete, you can summarize what you did using a PRISMA flow diagram .

Next, Boyle and colleagues found the full texts for each of the remaining studies. Boyle and Tang read through the articles to decide if any more studies needed to be excluded based on the selection criteria.

When Boyle and Tang disagreed about whether a study should be excluded, they discussed it with Varigos until the three researchers came to an agreement.

Step 5: Extract the data

Extracting the data means collecting information from the selected studies in a systematic way. There are two types of information you need to collect from each study:

Information about the study’s methods and results . The exact information will depend on your research question, but it might include the year, study design , sample size, context, research findings , and conclusions. If any data are missing, you’ll need to contact the study’s authors.
Your judgment of the quality of the evidence, including risk of bias .

You should collect this information using forms. You can find sample forms in The Registry of Methods and Tools for Evidence-Informed Decision Making and the Grading of Recommendations, Assessment, Development and Evaluations Working Group .

Extracting the data is also a three-person job. Two people should do this step independently, and the third person will resolve any disagreements.

They also collected data about possible sources of bias, such as how the study participants were randomized into the control and treatment groups.

Step 6: Synthesize the data

Synthesizing the data means bringing together the information you collected into a single, cohesive story. There are two main approaches to synthesizing the data:

Narrative ( qualitative ): Summarize the information in words. You’ll need to discuss the studies and assess their overall quality.
Quantitative : Use statistical methods to summarize and compare data from different studies. The most common quantitative approach is a meta-analysis , which allows you to combine results from multiple studies into a summary result.

Generally, you should use both approaches together whenever possible. If you don’t have enough data, or the data from different studies aren’t comparable, then you can take just a narrative approach. However, you should justify why a quantitative approach wasn’t possible.

Boyle and colleagues also divided the studies into subgroups, such as studies about babies, children, and adults, and analyzed the effect sizes within each group.

Step 7: Write and publish a report

The purpose of writing a systematic review article is to share the answer to your research question and explain how you arrived at this answer.

Your article should include the following sections:

Abstract : A summary of the review
Introduction : Including the rationale and objectives
Methods : Including the selection criteria, search method, data extraction method, and synthesis method
Results : Including results of the search and selection process, study characteristics, risk of bias in the studies, and synthesis results
Discussion : Including interpretation of the results and limitations of the review
Conclusion : The answer to your research question and implications for practice, policy, or research

To verify that your report includes everything it needs, you can use the PRISMA checklist .

Once your report is written, you can publish it in a systematic review database, such as the Cochrane Database of Systematic Reviews , and/or in a peer-reviewed journal.

In their report, Boyle and colleagues concluded that probiotics cannot be recommended for reducing eczema symptoms or improving quality of life in patients with eczema. Note Generative AI tools like ChatGPT can be useful at various stages of the writing and research process and can help you to write your systematic review. However, we strongly advise against trying to pass AI-generated text off as your own work.

If you want to know more about statistics , methodology , or research bias , make sure to check out some of our other articles with explanations and examples.

Student’s t -distribution
Normal distribution
Null and Alternative Hypotheses
Chi square tests
Confidence interval
Quartiles & Quantiles
Cluster sampling
Stratified sampling
Data cleansing
Reproducibility vs Replicability
Peer review
Prospective cohort study

Research bias

Implicit bias
Cognitive bias
Placebo effect
Hawthorne effect
Hindsight bias
Affect heuristic
Social desirability bias

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a thesis, dissertation , or research paper , in order to situate your work in relation to existing knowledge.

A literature review is a survey of credible sources on a topic, often used in dissertations , theses, and research papers . Literature reviews give an overview of knowledge on a subject, helping you identify relevant theories and methods, as well as gaps in existing research. Literature reviews are set up similarly to other academic texts , with an introduction , a main body, and a conclusion .

An annotated bibliography is a list of source references that has a short description (called an annotation ) for each of the sources. It is often assigned as part of the research process for a paper .

A systematic review is secondary research because it uses existing research. You don’t collect new data yourself.

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Why systematic reviews matter

July 23, 2019 | 7 min read

By Tina Poklepović Peričić, Sarah Tanveer

A brief history, overview and practical guide for authors

This article was written as part of the Cochrane International Mobility Programme.

Introduction

The vast scale of scholarly literature occasions various problems. One is how to comprehensively record and assess the state of knowledge on a particular topic. A potent means of doing so is that of systematic reviews. The continuous growth of research, coupled with the demand to systematically summarize the available evidence to inform decisions from consumers and stakeholders, led to the formal development of systematic reviews (SRs) in the late 20th century 1-3 .

Systematic reviews search, appraise and collate all relevant empirical evidence in order to provide a complete interpretation of research results. Although conventional SRs are typically used in clinical research and social sciences, they have found application in various other subject areas for example in advertising, education, international development, public policy, ecology, environmental sciences, engineering and basic science research 4-7

A brief history of systematic reviews

The first example of a systematic review was conducted in 1753 by James Lind, who published a paper that aimed to provide a concise and unbiased summary of evidence on scurvy 8 9 . However, it was not until the 1970’s and 1980’s when more attention was paid to the growing need to improve the state of evidence synthesis.

In 1972, Archie Cochrane published a textbook titled “ Effectiveness and Efficiency: Random Reflections on Health Service ” 10 . Cochrane drew attention to the vital importance of randomized control trials in determining the effectiveness of health treatments. This led to a greater international emphasis on the need to improve research synthesis by policy makers, academics, and clinicians 3 . Gradually, topic areas outside of healthcare also adopted SRs as a way of comprehensively and systemically summarizing existing research.

How to conduct a systematic review

If you are considering embarking on a systematic review, there are several issues you need to contemplate if you wish to conduct one. In healthcare, for example, the first step would be to define an explicit research question by using the PICOTS (Population, Intervention, Comparator, Outcome, Timing, Setting) framework 11 , and also register the protocol for the review on PROSPERO ( https://www.crd.york.ac.uk/prospero/ opens in new tab/window ), the international database of prospectively registered systematic reviews. Protocols provide a complete detailed description of the process by which the review will be conducted. Registering the protocol reduces research bias, duplication of effort, resource waste, and provides greater transparency 12 . Outside of medical sciences, protocols can be uploaded to Open Science Framework ( https://osf.io opens in new tab/window ).

You must adopt a comprehensive, objective and reproducible search strategy to capture all relevant sources of evidence. In doing so, you can be confident of having incorporated all the appropriate material for the topic at hand. A thorough search strategy should involve multiple databases, registries, sources of grey literature ( https://onlinelibrary.london.ac.uk/resources/databases/opengrey opens in new tab/window ) 13 , conference proceedings and abstracts. Following the predefined eligibility criteria, you then need to analyze the screened search results to extract data from those publications that meet the inclusion criteria.

Don’t forget to assess the risk of bias when applicable (i.e., in clinical research). Ideally, these methodological steps should preferably be performed by two authors independently, one of which is a methodologist and the other a content area expert. Summarizing the results of the included studies and interpreting their findings in the light of certainty of evidence and their applicability are the final steps of completing a systematic review. You can also include a meta-analysis if applicable.

In order to assess the methodological quality of systematic reviews in biomedical sciences, checklists like the AMSTAR – “A MeaSurement Tool to Assess systematic Reviews" 14 (https://amstar.ca) can be utilized. Lastly, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 16 (https://prisma-statement.org/) checklist, is a minimum set of items for reporting in systematic reviews: include one with your full article. The flow diagram can also be adopted to use for non-medical research (https://prisma-statement.org/PRISMAStatement/FlowDiagram).

Why are systematic reviews important?

Systematic reviews offer a number of benefits. For starters, they deliver a clear and comprehensive overview of available evidence on a given topic. Moreover, SRs also help identify research gaps in our current understanding of a field. They can highlight methodological concerns in research studies that can be used to improve future work in the topic area 17 . Lastly, they can be used to identify questions for which the available evidence provide clear answers and thus for which further research is not necessary 18 .

The process of conducting systematic reviews, especially for new authors, will prove to be a worthwhile endeavour. Authors refine their knowledge on the subject area of interest, develop new research ideas, and gain critical skills in synthesising existing literature.

We hope that you have found this introduction to systematic reviews helpful. Additional information about SRs can be found on the Cochrane website opens in new tab/window . If you have any questions or observations, please feel free to comment below.

1. Meerpohl JJ, Herrle F, Reinders S, et al. Scientific value of systematic reviews: survey of editors of core clinical journals. PLoS One 2012;7(5):e35732. doi: 10.1371/journal.pone.0035732 [published Online First: 2012/05/09]

2. Higgins JPT, Green S, Cochrane Collaboration. Cochrane handbook for systematic reviews of interventions Version 5.1.0 [updated March 2011]. London: The Cochrane Collaboration,, 2011:1 online resource. doi: 10.1002/9780470712184

3. Chalmers I, Hedges LV, Cooper H. A brief history of research synthesis. Eval Health Prof 2002;25(1):12-37. doi: 10.1177/0163278702025001003 [published Online First: 2002/03/01]

4. O’Hagan EC, Matalon S, Riesenberg LA. Systematic reviews of the literature: a better way of addressing basic science controversies: American Physiological Society Bethesda, MD, 2018. doi: 10.1152/ajplung.00544.2017

5. Gilbody S, Wilson P, Watt I. Benefits and harms of direct to consumer advertising: a systematic review. BMJ Quality & Safety 2005;14(4):246-50. doi: 10.1136/qshc.2004.012781

6. Pullin AS, Stewart GB. Guidelines for systematic review in conservation and environmental management. Conservation biology 2006;20(6):1647-56. doi: 10.1111/j.1523-1739.2006.00485.x

7. Petticrew M. Systematic reviews from astronomy to zoology: myths and misconceptions. Bmj 2001;322(7278):98-101. doi: 10.1136/bmj.322.7278.98

8. Lind J. A treatise on the scurvy. In three parts. Containing an inquiry into the nature, causes, and cure, of that disease. London,: A. Millar 1753. doi:10.1136/bmj.330.7482.92-a

9. Clarke M, Chalmers I. Reflections on the history of systematic reviews. BMJ Evid Based Med 2018;23(4):121-22. doi: 10.1136/bmjebm-2018-110968 [published Online First: 2018/06/21]

10. Cochrane AL. Effectiveness and efficiency: random reflections on health services. London: Nuffield Provincial Hospitals Trust 1972. doi: 10.1017/cbo9781107256644

11. Santos CMdC, Pimenta CAdM, Nobre MRC. The PICO strategy for the research question construction and evidence search. Revista latino-americana de enfermagem 2007;15(3):508-11. doi: 10.1590/s0104-11692007000300023

12. Stewart L, Moher D, Shekelle P. Why prospective registration of systematic reviews makes sense. Syst Rev 2012;1:7. doi: 10.1186/2046-4053-1-7 [published Online First: 2012/05/17]

13. Mahood Q, Van Eerd D, Irvin E. Searching for grey literature for systematic reviews: challenges and benefits. Research synthesis methods 2014;5(3):221-34. doi: 10.1002/jrsm.1106

14. Shea BJ, Reeves BC, Wells G, et al. AMSTAR 2: a critical appraisal tool for systematic reviews that include randomised or non-randomised studies of healthcare interventions, or both. Bmj 2017;358:j4008. doi: 10.1136/bmj.j4008

15. Chandler J, Churchill R, Higgins J, et al. Methodological standards for the conduct of new Cochrane Intervention Reviews. The Cochrane Library 2013 doi: 10.4073/cpg.2016.3

16. Moher D, Liberati A, Tetzlaff J, et al. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. Annals of internal medicine 2009;151(4):264-69. doi: 10.7326/0003-4819-151-4-200908180-00135

17. Eagly AH, Wood W. Using research syntheses to plan future research. The Handbook of Research Synthesis: Russell Sage Foundation 1994:485-500. doi: 10.1002/(SICI)1097-0258(19970330)16:6<713::AID-SIM430>3.0.CO;2-4

18. Chalmers I, Glasziou P. Avoidable waste in the production and reporting of research evidence. Obstet Gynecol 2009;114(6):1341-5. doi: 10.1097/AOG.0b013e3181c3020d [published Online First: 2009/11/26]

Contributors

Tina Poklepović Peričić

Medical School

Sarah Tanveer

University Libraries University of Nevada, Reno

Skill Guides
Subject Guides

Systematic, Scoping, and Other Literature Reviews: Overview

Project Planning

What Is a Systematic Review?

Regular literature reviews are simply summaries of the literature on a particular topic. A systematic review, however, is a comprehensive literature review conducted to answer a specific research question. Authors of a systematic review aim to find, code, appraise, and synthesize all of the previous research on their question in an unbiased and well-documented manner. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) outline the minimum amount of information that needs to be reported at the conclusion of a systematic review project.

Other types of what are known as "evidence syntheses," such as scoping, rapid, and integrative reviews, have varying methodologies. While systematic reviews originated with and continue to be a popular publication type in medicine and other health sciences fields, more and more researchers in other disciplines are choosing to conduct evidence syntheses.

This guide will walk you through the major steps of a systematic review and point you to key resources including Covidence, a systematic review project management tool. For help with systematic reviews and other major literature review projects, please send us an email at [email protected] .

Getting Help with Reviews

Organization such as the Institute of Medicine recommend that you consult a librarian when conducting a systematic review. Librarians at the University of Nevada, Reno can help you:

Understand best practices for conducting systematic reviews and other evidence syntheses in your discipline
Choose and formulate a research question
Decide which review type (e.g., systematic, scoping, rapid, etc.) is the best fit for your project
Determine what to include and where to register a systematic review protocol
Select search terms and develop a search strategy
Identify databases and platforms to search
Find the full text of articles and other sources
Become familiar with free citation management (e.g., EndNote, Zotero)
Get access to you and help using Covidence, a systematic review project management tool

Doing a Systematic Review

Plan - This is the project planning stage. You and your team will need to develop a good research question, determine the type of review you will conduct (systematic, scoping, rapid, etc.), and establish the inclusion and exclusion criteria (e.g., you're only going to look at studies that use a certain methodology). All of this information needs to be included in your protocol. You'll also need to ensure that the project is viable - has someone already done a systematic review on this topic? Do some searches and check the various protocol registries to find out.
Identify - Next, a comprehensive search of the literature is undertaken to ensure all studies that meet the predetermined criteria are identified. Each research question is different, so the number and types of databases you'll search - as well as other online publication venues - will vary. Some standards and guidelines specify that certain databases (e.g., MEDLINE, EMBASE) should be searched regardless. Your subject librarian can help you select appropriate databases to search and develop search strings for each of those databases.
Evaluate - In this step, retrieved articles are screened and sorted using the predetermined inclusion and exclusion criteria. The risk of bias for each included study is also assessed around this time. It's best if you import search results into a citation management tool (see below) to clean up the citations and remove any duplicates. You can then use a tool like Rayyan (see below) to screen the results. You should begin by screening titles and abstracts only, and then you'll examine the full text of any remaining articles. Each study should be reviewed by a minimum of two people on the project team.
Collect - Each included study is coded and the quantitative or qualitative data contained in these studies is then synthesized. You'll have to either find or develop a coding strategy or form that meets your needs.
Explain - The synthesized results are articulated and contextualized. What do the results mean? How have they answered your research question?
Summarize - The final report provides a complete description of the methods and results in a clear, transparent fashion.

Adapted from

Types of reviews, systematic review.

These types of studies employ a systematic method to analyze and synthesize the results of numerous studies. "Systematic" in this case means following a strict set of steps - as outlined by entities like PRISMA and the Institute of Medicine - so as to make the review more reproducible and less biased. Consistent, thorough documentation is also key. Reviews of this type are not meant to be conducted by an individual but rather a (small) team of researchers. Systematic reviews are widely used in the health sciences, often to find a generalized conclusion from multiple evidence-based studies.

Meta-Analysis

A systematic method that uses statistics to analyze the data from numerous studies. The researchers combine the data from studies with similar data types and analyze them as a single, expanded dataset. Meta-analyses are a type of systematic review.

Scoping Review

A scoping review employs the systematic review methodology to explore a broader topic or question rather than a specific and answerable one, as is generally the case with a systematic review. Authors of these types of reviews seek to collect and categorize the existing literature so as to identify any gaps.

Rapid Review

Rapid reviews are systematic reviews conducted under a time constraint. Researchers make use of workarounds to complete the review quickly (e.g., only looking at English-language publications), which can lead to a less thorough and more biased review.

Narrative Review

A traditional literature review that summarizes and synthesizes the findings of numerous original research articles. The purpose and scope of narrative literature reviews vary widely and do not follow a set protocol. Most literature reviews are narrative reviews.

Umbrella Review

Umbrella reviews are, essentially, systematic reviews of systematic reviews. These compile evidence from multiple review studies into one usable document.

Grant, Maria J., and Andrew Booth. “A Typology of Reviews: An Analysis of 14 Review Types and Associated Methodologies.” Health Information & Libraries Journal , vol. 26, no. 2, 2009, pp. 91-108. doi: 10.1111/j.1471-1842.2009.00848.x .

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What are systematic reviews?

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Systematic reviews are a type of literature review of research which require equivalent standards of rigour as primary research. They have a clear, logical rationale that is reported to the reader of the review. They are used in research and policymaking to inform evidence-based decisions and practice. They differ from traditional literature reviews particularly in the following elements of conduct and reporting.

Systematic reviews:

use explicit and transparent methods
are a piece of research following a standard set of stages
are accountable, replicable and updateable
involve users to ensure a review is relevant and useful.

For example, systematic reviews (like all research) should have a clear research question, and the perspective of the authors in their approach to addressing the question is described. There are clearly described methods on how each study in a review was identified, how that study was appraised for quality and relevance and how it is combined with other studies in order to address the review question. A systematic review usually involves more than one person in order to increase the objectivity and trustworthiness of the reviews methods and findings.

Research protocols for systematic reviews may be peer-reviewed and published or registered in a suitable repository to help avoid duplication of reviews and for comparisons to be made with the final review and the planned review.

History of systematic reviews to inform policy (EPPI-Centre)
Six reasons why it is important to be systematic (EPPI-Centre)
Evidence Synthesis International (ESI): Position Statement Describes the issues, principles and goals in synthesising research evidence to inform policy, practice and decisions

A 'non-systematic review' might use some of the same methods as systematic reviews, such as systematic approaches to identify studies or quality appraise the literature. There may be times when this approach can be useful. In a student dissertation, for example, there may not be the time to be fully systematic in a review of the literature if this is only one small part of the thesis. In other types of research, there may also be a need to obtain a quick and not necessarily thorough overview of a literature to inform some other work (including a systematic review). Another example, is where policymakers, or other people using research findings, want to make quick decisions and there is no systematic review available to help them. They have a choice of gaining a rapid overview of the research literature or not having any research evidence to help their decision-making.

Just like any other piece of research, the methods used to undertake any literature review should be carefully planned to justify the conclusions made.

Finding out about different types of systematic reviews and the methods used for systematic reviews, and reading both systematic and other types of review will help to understand some of the differences.

Typically, a systematic review addresses a focussed, structured research question in order to inform understanding and decisions on an area. (see the Formulating a research question section for examples).

Sometimes systematic reviews ask a broad research question, and one strategy to achieve this is the use of several focussed sub-questions each addressed by sub-components of the review.

Another strategy is to develop a map to describe the type of research that has been undertaken in relation to a research question. Some maps even describe over 2,000 papers, while others are much smaller. One purpose of a map is to help choose a sub-set of studies to explore more fully in a synthesis. There are also other purposes of maps: see the box on systematic evidence maps for further information.

Reporting standards specify minimum elements that need to go into the reporting of a review. The reporting standards refer mainly to methodological issues but they are not as detailed or specific as critical appraisal for the methodological standards of conduct of a review.

A number of organisations have developed specific guidelines and standards for both the conducting and reporting on systematic reviews in different topic areas.

PRISMA PRISMA is a reporting standard and is an acronym for Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The Key Documents section of the PRISMA website links to a checklist, flow diagram and explanatory notes. PRISMA is less useful for certain types of reviews, including those that are iterative.
eMERGe eMERGe is a reporting standard that has been developed for meta-ethnographies, a qualitative synthesis method.
ROSES: RepOrting standards for Systematic Evidence Syntheses Reporting standards, including forms and flow diagram, designed specifically for systematic reviews and maps in the field of conservation and environmental management.

Useful books about systematic reviews

Systematic approaches to a successful literature review

An introduction to systematic reviews

Cochrane handbook for systematic reviews of interventions

Systematic reviews: crd's guidance for undertaking reviews in health care.

Finding what works in health care: Standards for systematic reviews

Systematic Reviews in the Social Sciences

Meta-analysis and research synthesis.

Research Synthesis and Meta-Analysis

Doing a Systematic Review

Literature reviews.

What is a literature review?
Why are literature reviews important?
<< Previous: Systematic reviews
Next: Types of systematic reviews >>
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How to Do a Systematic Review: A Best Practice Guide for Conducting and Reporting Narrative Reviews, Meta-Analyses, and Meta-Syntheses

Affiliations.

1 Behavioural Science Centre, Stirling Management School, University of Stirling, Stirling FK9 4LA, United Kingdom; email: [email protected].
2 Department of Psychological and Behavioural Science, London School of Economics and Political Science, London WC2A 2AE, United Kingdom.
3 Department of Statistics, Northwestern University, Evanston, Illinois 60208, USA; email: [email protected].
PMID: 30089228
DOI: 10.1146/annurev-psych-010418-102803

Systematic reviews are characterized by a methodical and replicable methodology and presentation. They involve a comprehensive search to locate all relevant published and unpublished work on a subject; a systematic integration of search results; and a critique of the extent, nature, and quality of evidence in relation to a particular research question. The best reviews synthesize studies to draw broad theoretical conclusions about what a literature means, linking theory to evidence and evidence to theory. This guide describes how to plan, conduct, organize, and present a systematic review of quantitative (meta-analysis) or qualitative (narrative review, meta-synthesis) information. We outline core standards and principles and describe commonly encountered problems. Although this guide targets psychological scientists, its high level of abstraction makes it potentially relevant to any subject area or discipline. We argue that systematic reviews are a key methodology for clarifying whether and how research findings replicate and for explaining possible inconsistencies, and we call for researchers to conduct systematic reviews to help elucidate whether there is a replication crisis.

Keywords: evidence; guide; meta-analysis; meta-synthesis; narrative; systematic review; theory.

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How to write a systematic literature review [9 steps]

What is a systematic literature review?

Where are systematic literature reviews used, what types of systematic literature reviews are there, how to write a systematic literature review, 1. decide on your team, 2. formulate your question, 3. plan your research protocol, 4. search for the literature, 5. screen the literature, 6. assess the quality of the studies, 7. extract the data, 8. analyze the results, 9. interpret and present the results, registering your systematic literature review, frequently asked questions about writing a systematic literature review, related articles.

A systematic literature review is a summary, analysis, and evaluation of all the existing research on a well-formulated and specific question.

Put simply, a systematic review is a study of studies that is popular in medical and healthcare research. In this guide, we will cover:

the definition of a systematic literature review
the purpose of a systematic literature review
the different types of systematic reviews
how to write a systematic literature review

➡️ Visit our guide to the best research databases for medicine and health to find resources for your systematic review.

Systematic literature reviews can be utilized in various contexts, but they’re often relied on in clinical or healthcare settings.

Medical professionals read systematic literature reviews to stay up-to-date in their field, and granting agencies sometimes need them to make sure there’s justification for further research in an area. They can even be used as the starting point for developing clinical practice guidelines.

A classic systematic literature review can take different approaches:

Effectiveness reviews assess the extent to which a medical intervention or therapy achieves its intended effect. They’re the most common type of systematic literature review.
Diagnostic test accuracy reviews produce a summary of diagnostic test performance so that their accuracy can be determined before use by healthcare professionals.
Experiential (qualitative) reviews analyze human experiences in a cultural or social context. They can be used to assess the effectiveness of an intervention from a person-centric perspective.
Costs/economics evaluation reviews look at the cost implications of an intervention or procedure, to assess the resources needed to implement it.
Etiology/risk reviews usually try to determine to what degree a relationship exists between an exposure and a health outcome. This can be used to better inform healthcare planning and resource allocation.
Psychometric reviews assess the quality of health measurement tools so that the best instrument can be selected for use.
Prevalence/incidence reviews measure both the proportion of a population who have a disease, and how often the disease occurs.
Prognostic reviews examine the course of a disease and its potential outcomes.
Expert opinion/policy reviews are based around expert narrative or policy. They’re often used to complement, or in the absence of, quantitative data.
Methodology systematic reviews can be carried out to analyze any methodological issues in the design, conduct, or review of research studies.

Writing a systematic literature review can feel like an overwhelming undertaking. After all, they can often take 6 to 18 months to complete. Below we’ve prepared a step-by-step guide on how to write a systematic literature review.

Decide on your team.
Formulate your question.
Plan your research protocol.
Search for the literature.
Screen the literature.
Assess the quality of the studies.
Extract the data.
Analyze the results.
Interpret and present the results.

When carrying out a systematic literature review, you should employ multiple reviewers in order to minimize bias and strengthen analysis. A minimum of two is a good rule of thumb, with a third to serve as a tiebreaker if needed.

You may also need to team up with a librarian to help with the search, literature screeners, a statistician to analyze the data, and the relevant subject experts.

Define your answerable question. Then ask yourself, “has someone written a systematic literature review on my question already?” If so, yours may not be needed. A librarian can help you answer this.

You should formulate a “well-built clinical question.” This is the process of generating a good search question. To do this, run through PICO:

Patient or Population or Problem/Disease : who or what is the question about? Are there factors about them (e.g. age, race) that could be relevant to the question you’re trying to answer?
Intervention : which main intervention or treatment are you considering for assessment?
Comparison(s) or Control : is there an alternative intervention or treatment you’re considering? Your systematic literature review doesn’t have to contain a comparison, but you’ll want to stipulate at this stage, either way.
Outcome(s) : what are you trying to measure or achieve? What’s the wider goal for the work you’ll be doing?

Now you need a detailed strategy for how you’re going to search for and evaluate the studies relating to your question.

The protocol for your systematic literature review should include:

the objectives of your project
the specific methods and processes that you’ll use
the eligibility criteria of the individual studies
how you plan to extract data from individual studies
which analyses you’re going to carry out

For a full guide on how to systematically develop your protocol, take a look at the PRISMA checklist . PRISMA has been designed primarily to improve the reporting of systematic literature reviews and meta-analyses.

When writing a systematic literature review, your goal is to find all of the relevant studies relating to your question, so you need to search thoroughly .

This is where your librarian will come in handy again. They should be able to help you formulate a detailed search strategy, and point you to all of the best databases for your topic.

➡️ Read more on on how to efficiently search research databases .

The places to consider in your search are electronic scientific databases (the most popular are PubMed , MEDLINE , and Embase ), controlled clinical trial registers, non-English literature, raw data from published trials, references listed in primary sources, and unpublished sources known to experts in the field.

➡️ Take a look at our list of the top academic research databases .

Tip: Don’t miss out on “gray literature.” You’ll improve the reliability of your findings by including it.

Don’t miss out on “gray literature” sources: those sources outside of the usual academic publishing environment. They include:

non-peer-reviewed journals
pharmaceutical industry files
conference proceedings
pharmaceutical company websites
internal reports

Gray literature sources are more likely to contain negative conclusions, so you’ll improve the reliability of your findings by including it. You should document details such as:

The databases you search and which years they cover
The dates you first run the searches, and when they’re updated
Which strategies you use, including search terms
The numbers of results obtained

➡️ Read more about gray literature .

This should be performed by your two reviewers, using the criteria documented in your research protocol. The screening is done in two phases:

Pre-screening of all titles and abstracts, and selecting those appropriate
Screening of the full-text articles of the selected studies

Make sure reviewers keep a log of which studies they exclude, with reasons why.

➡️ Visit our guide on what is an abstract?

Your reviewers should evaluate the methodological quality of your chosen full-text articles. Make an assessment checklist that closely aligns with your research protocol, including a consistent scoring system, calculations of the quality of each study, and sensitivity analysis.

The kinds of questions you'll come up with are:

Were the participants really randomly allocated to their groups?
Were the groups similar in terms of prognostic factors?
Could the conclusions of the study have been influenced by bias?

Every step of the data extraction must be documented for transparency and replicability. Create a data extraction form and set your reviewers to work extracting data from the qualified studies.

Here’s a free detailed template for recording data extraction, from Dalhousie University. It should be adapted to your specific question.

Establish a standard measure of outcome which can be applied to each study on the basis of its effect size.

Measures of outcome for studies with:

Binary outcomes (e.g. cured/not cured) are odds ratio and risk ratio
Continuous outcomes (e.g. blood pressure) are means, difference in means, and standardized difference in means
Survival or time-to-event data are hazard ratios

Design a table and populate it with your data results. Draw this out into a forest plot , which provides a simple visual representation of variation between the studies.

Then analyze the data for issues. These can include heterogeneity, which is when studies’ lines within the forest plot don’t overlap with any other studies. Again, record any excluded studies here for reference.

Consider different factors when interpreting your results. These include limitations, strength of evidence, biases, applicability, economic effects, and implications for future practice or research.

Apply appropriate grading of your evidence and consider the strength of your recommendations.

It’s best to formulate a detailed plan for how you’ll present your systematic review results. Take a look at these guidelines for interpreting results from the Cochrane Institute.

Before writing your systematic literature review, you can register it with OSF for additional guidance along the way. You could also register your completed work with PROSPERO .

Systematic literature reviews are often found in clinical or healthcare settings. Medical professionals read systematic literature reviews to stay up-to-date in their field and granting agencies sometimes need them to make sure there’s justification for further research in an area.

The first stage in carrying out a systematic literature review is to put together your team. You should employ multiple reviewers in order to minimize bias and strengthen analysis. A minimum of two is a good rule of thumb, with a third to serve as a tiebreaker if needed.

Your systematic review should include the following details:

A literature review simply provides a summary of the literature available on a topic. A systematic review, on the other hand, is more than just a summary. It also includes an analysis and evaluation of existing research. Put simply, it's a study of studies.

The final stage of conducting a systematic literature review is interpreting and presenting the results. It’s best to formulate a detailed plan for how you’ll present your systematic review results, guidelines can be found for example from the Cochrane institute .

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Systematic Literature Review or Literature Review?

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Table of Contents

As a researcher, you may be required to conduct a literature review. But what kind of review do you need to complete? Is it a systematic literature review or a standard literature review? In this article, we’ll outline the purpose of a systematic literature review, the difference between literature review and systematic review, and other important aspects of systematic literature reviews.

What is a Systematic Literature Review?

The purpose of systematic literature reviews is simple. Essentially, it is to provide a high-level of a particular research question. This question, in and of itself, is highly focused to match the review of the literature related to the topic at hand. For example, a focused question related to medical or clinical outcomes.

The components of a systematic literature review are quite different from the standard literature review research theses that most of us are used to (more on this below). And because of the specificity of the research question, typically a systematic literature review involves more than one primary author. There’s more work related to a systematic literature review, so it makes sense to divide the work among two or three (or even more) researchers.

Your systematic literature review will follow very clear and defined protocols that are decided on prior to any review. This involves extensive planning, and a deliberately designed search strategy that is in tune with the specific research question. Every aspect of a systematic literature review, including the research protocols, which databases are used, and dates of each search, must be transparent so that other researchers can be assured that the systematic literature review is comprehensive and focused.

Most systematic literature reviews originated in the world of medicine science. Now, they also include any evidence-based research questions. In addition to the focus and transparency of these types of reviews, additional aspects of a quality systematic literature review includes:

Clear and concise review and summary
Comprehensive coverage of the topic
Accessibility and equality of the research reviewed

Systematic Review vs Literature Review

The difference between literature review and systematic review comes back to the initial research question. Whereas the systematic review is very specific and focused, the standard literature review is much more general. The components of a literature review, for example, are similar to any other research paper. That is, it includes an introduction, description of the methods used, a discussion and conclusion, as well as a reference list or bibliography.

A systematic review, however, includes entirely different components that reflect the specificity of its research question, and the requirement for transparency and inclusion. For instance, the systematic review will include:

Eligibility criteria for included research
A description of the systematic research search strategy
An assessment of the validity of reviewed research
Interpretations of the results of research included in the review

As you can see, contrary to the general overview or summary of a topic, the systematic literature review includes much more detail and work to compile than a standard literature review. Indeed, it can take years to conduct and write a systematic literature review. But the information that practitioners and other researchers can glean from a systematic literature review is, by its very nature, exceptionally valuable.

This is not to diminish the value of the standard literature review. The importance of literature reviews in research writing is discussed in this article . It’s just that the two types of research reviews answer different questions, and, therefore, have different purposes and roles in the world of research and evidence-based writing.

Systematic Literature Review vs Meta Analysis

It would be understandable to think that a systematic literature review is similar to a meta analysis. But, whereas a systematic review can include several research studies to answer a specific question, typically a meta analysis includes a comparison of different studies to suss out any inconsistencies or discrepancies. For more about this topic, check out Systematic Review VS Meta-Analysis article.

Language Editing Plus

With Elsevier’s Language Editing Plus services , you can relax with our complete language review of your systematic literature review or literature review, or any other type of manuscript or scientific presentation. Our editors are PhD or PhD candidates, who are native-English speakers. Language Editing Plus includes checking the logic and flow of your manuscript, reference checks, formatting in accordance to your chosen journal and even a custom cover letter. Our most comprehensive editing package, Language Editing Plus also includes any English-editing needs for up to 180 days.

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What is a Systematic Review?

Types of Reviews
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Our Service
1. Assemble Your Team
2. Develop a Research Question
3. Write and Register a Protocol
4. Search the Evidence
5. Screen Results
6. Assess for Quality and Bias
7. Extract the Data
8. Write the Review
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A systematic review attempts to collate all empirical evidence that fits pre-specified eligibility criteria in order to answer a specific research question. The key characteristics of a systematic review are:

a clearly defined question with inclusion and exclusion criteria;
a rigorous and systematic search of the literature;
two phases of screening (blinded, at least two independent screeners);
data extraction and management;
analysis and interpretation of results;
risk of bias assessment of included studies;
and report for publication.

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The following presentation is a recording of the Getting Started with Systematic Reviews workshop (4/2022), offered by the Duke Medical Center Library & Archives. A NetID/pw is required to access the tutorial via Warpwire.

<< Previous: Overview
Next: Types of Reviews >>
Last Updated: Jun 18, 2024 9:41 AM
URL: https://guides.mclibrary.duke.edu/sysreview
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Systematic Reviews

What is a Systematic Review?

A systematic review is an evidence synthesis that uses explicit, reproducible methods to perform a comprehensive literature search and critical appraisal of individual studies and that uses appropriate statistical techniques to combine these valid studies.

Key Characteristics of a Systematic Review:

Generally, systematic reviews must have:

a clearly stated set of objectives with pre-defined eligibility criteria for studies
an explicit, reproducible methodology
a systematic search that attempts to identify all studies that would meet the eligibility criteria
an assessment of the validity of the findings of the included studies, for example through the assessment of the risk of bias
a systematic presentation, and synthesis, of the characteristics and findings of the included studies.

A meta-analysis is a systematic review that uses quantitative methods to synthesize and summarize the pooled data from included studies.

Additional Information

How-to Books
Beyond Health Sciences

Cochrane Handbook For Systematic Reviews of Interventions Provides guidance to authors for the preparation of Cochrane Intervention reviews. Chapter 6 covers searching for reviews.
Systematic Reviews: CRD’s Guidance for Undertaking Reviews in Health Care From The University of York Centre for Reviews and Dissemination: Provides practical guidance for undertaking evidence synthesis based on a thorough understanding of systematic review methodology. It presents the core principles of systematic reviewing, and in complementary chapters, highlights issues that are specific to reviews of clinical tests, public health interventions, adverse effects, and economic evaluations.
Cornell, Sytematic Reviews and Evidence Synthesis Beyond the Health Sciences Video series geared for librarians but very informative about searching outside medicine.
<< Previous: Getting Started
Next: Levels of Evidence >>
Getting Started
Levels of Evidence
Locating Systematic Reviews
Searching Systematically
Developing Answerable Questions
Identifying Synonyms & Related Terms
Using Truncation and Wildcards
Identifying Search Limits/Exclusion Criteria
Keyword vs. Subject Searching
Where to Search
Search Filters
Sensitivity vs. Precision
Core Databases
Other Databases
Clinical Trial Registries
Conference Presentations
Databases Indexing Grey Literature
Web Searching
Handsearching
Citation Indexes
Documenting the Search Process
Managing your Review

Research Support

Last Updated: Jun 6, 2024 9:14 AM
URL: https://guides.library.ucdavis.edu/systematic-reviews

Doing a Systematic Review: A Student’s Guide

Saul Mcleod, PhD

Editor-in-Chief for Simply Psychology

BSc (Hons) Psychology, MRes, PhD, University of Manchester

Saul Mcleod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.

Learn about our Editorial Process

Olivia Guy-Evans, MSc

Associate Editor for Simply Psychology

BSc (Hons) Psychology, MSc Psychology of Education

Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.

What is Systematic Review?

A systematic review is a comprehensive, structured analysis of existing research on a specific topic. It uses predefined criteria to identify, evaluate, and synthesize relevant studies, aiming to provide an unbiased summary of the current evidence.

The explicit and systematic approach of a systematic review distinguishes it from traditional reviews and commentaries.

Here are some key ways that systematic reviews differ from narrative reviews:

Goals: Narrative reviews provide a summary or overview of a topic, while systematic reviews answer a focused review question.
Sources of Literature: Narrative reviews often use a non-exhaustive and unstated body of literature, which can lead to publication bias. Systematic reviews consider a list of databases, grey literature, and other sources.
Selection Criteria: Narrative reviews usually use subjective or no selection criteria, which can lead to selection bias. Systematic reviews have a clear and explicit selection process.
Appraisal of Study Quality: Narrative reviews vary in their evaluation of study quality. Systematic reviews use standard checklists for a rigorous appraisal of study quality.

Systematic reviews are time-intensive and need a research team with multiple skills and contributions. There are some cases where systematic reviews are unable to meet the necessary objectives of the review question.

In these cases, scoping reviews (which are sometimes called scoping exercises/scoping studies) may be more useful to consider.

Scoping reviews are different from systematic reviews because they may not include a mandatory critical appraisal of the included studies or synthesize the findings from individual studies.

Assessing The Need For A Systematic Review

When assessing the need for a systematic review, one must first check if any existing or ongoing reviews already exist and determine if a new review is justified.

This process should begin by searching relevant databases.

Resources to consider searching include:

NICE : National Institute for Health and Clinical Excellence
Campbell Library of Systematic Reviews for reviews in education, crime and justice, and social welfare
EPPI : Evidence for Policy and Practice Information Centre, particularly their database of systematic and non-systematic reviews of public health interventions (DoPHER)
MEDLINE : Primarily covers the medical domain, making it a primary resource for systematic reviews concerning healthcare interventions
PsycINFO : For research in psychology, psychiatry, behavioral sciences, and social sciences
Cochrane Library (specifically CDSR) : Focuses on systematic reviews of health care interventions, providing regularly updated and critically appraised reviews

If an existing review addressing the question of interest is found, its quality should be assessed to determine its suitability for guiding policy and practice.

If a high-quality, relevant review is located, but its completion date is some time ago, updating the review might be warranted.

Assessing current relevance is vital, especially in rapidly evolving research fields. Collaboration with the original research team might be beneficial during the update process, as they could provide access to their data.

If the review is deemed to be of adequate quality and remains relevant, undertaking another systematic review may not be necessary.

When a new systematic review or an update is deemed necessary, the subsequent step involves establishing a review team and potentially an advisory group, who will then develop the review protocol.

How To Conduct A Systematic Review

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) is a reporting guideline designed to improve the transparency and completeness of systematic review reporting.

PRISMA was created to tackle the issue of inadequate reporting often found in systematic reviews:

Checklist : PRISMA features a 27-item checklist covering all aspects of a systematic review, from the rationale and objectives to the synthesis of findings and discussion of limitations. Each checklist item is accompanied by detailed reporting recommendations in an Explanation and Elaboration document .
Flow Diagram : PRISMA also includes a flow diagram to visually represent the study selection process, offering a clear, standardized way to illustrate how researchers arrived at the final set of included studies.

Step 1: write a research protocol

A protocol in the context of systematic reviews is a detailed plan that outlines the methodology to be employed throughout the review process.

The protocol serves as a roadmap, guiding researchers through each stage of the review in a transparent and replicable manner.

This document should provide specific details about every stage of the research process, including the methodology for identifying, selecting, and analyzing relevant studies.

For example, the protocol should specify search strategies for relevant studies, including whether the search will encompass unpublished works.

The protocol should be created before beginning the research process to ensure transparency and reproducibility.

This pre-determined plan ensures that decisions made during the review are objective and free from bias, as they are based on pre-established criteria.

Protocol modifications are sometimes necessary during systematic reviews. While adhering to the protocol is crucial for minimizing bias, there are instances where modifications are justified. For instance, a deeper understanding of the research question that emerges from examining primary research might necessitate changes to the protocol.

Systematic reviews should be registered at inception (at the protocol stage) for these reasons:

To help avoid unplanned duplication
To enable the comparison of reported review methods with what was planned in the protocol

This registration prevents duplication (research waste) and makes the process easy when the full systematic review is sent for publication.

PROSPERO is an international database of prospectively registered systematic reviews in health and social care. Non-Cochrane protocols should be registered on PROSPERO.

Research Protocol

Rasika Jayasekara, Nicholas Procter. The effects of cognitive behaviour therapy for major depression in older adults: a systematic review. PROSPERO 2012 CRD42012003151 Available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42012003151

Review question

How effective is CBT compared with other interventions, placebo or standard treatment in achieving relapse prevention and improving mental status for older adults with major depression?

The search strategy aims to find both published and unpublished studies and publications. The search will be limited to English language papers published from 2002 to 2012.

A three-step search strategy will be developed using MeSH terminology and keywords to ensure that all materials relevant to the review are captured.

An initial limited search of MEDLINE and CINAHL will be undertaken followed by an analysis of the text words contained in the title and abstract, and of the index terms used to describe the article. A second search using all identified keywords and index terms will then be undertaken.

Thirdly, the reference list of all identified reports and articles will be searched for additional studies.

The databases to be searched included:

Cochrane Central Register of Controlled Trials
Controlled Trials
Current Contents

The search for unpublished studies will include:

Digital Dissertations (Proquest)
Conference Proceedings

Experts in the field will be contacted for ongoing and unpublished trials. Experts will be identified through journal publications.

Types of study to be included

All randomised controlled trials (RCTs) assessing the effectiveness of CBT as a treatment for older adults with major depression when compared to standard care, specific medication, other therapies and no intervention will be considered.

In the absence of RCTs, other research designs such as quasi-experimental studies, case-controlled studies and cohort studies will be examined. However, descriptive studies and expert opinion will be excluded.

Condition or domain being studied

Major depression is diagnosed according to DSM IV or ICD 10 criteria.

Where trials fail to employ diagnostic criteria, the severity of depression will be described by the use of standardised rating scales, including the Hamilton Depression Rating Scale, Montgomery and Asberg Rating Scale and the Geriatric Depression Rating Scale.

The trials including participants with an explicit diagnosis of dementia or Parkinson’s disease and other mental illnesses will be excluded.

The review will include trials conducted in primary, secondary, community, nursing homes and in-patient settings.

Participants/population

The review will include trials in which patients are described as elderly, geriatric, or older adults, or in which all patients will be aged 55 or over (many North American trials of older adult populations use a cut-off of 55 years).

The review will include trials with subjects of either sex. Where possible, participants will be categorised as community or long term care residents.

Intervention(s), exposure(s)

The review will focus on interventions designed to assess the effects of CBT for older adults with major depression.

The label cognitive behavioural therapy has been applied to a variety of interventions and, accordingly, it is difficult to provide a single, unambiguous definition.

In order to be classified as CBT the intervention must clearly demonstrate the following components:

the intervention involves the recipient establishing links between their thoughts, feelings and actions with respect to the target symptom;
the intervention involves the correction of the person’s misperceptions, irrational beliefs and reasoning biases related to the target symptom.
– the recipient monitoring his or her own thoughts, feelings and behaviours with respect to the target symptom; and
– the promotion of alternative ways of coping with the target symptom.

In addition, all therapies that do not meet these criteria (or that provide insufficient information) but are labelled as ‘CBT’ or ‘Cognitive Therapy’ will be included as ‘less well defined’ CBT.

Comparator(s)/control

other interventions, placebo or standard treatment

Main outcome(s)

Primary outcomes

Depression level as assessed by Hamilton Depression Rating Scale, Montgomery or Asberg Rating Scale or the Geriatric Depression Rating Scale.
Relapse (as defined in the individual studies)
Death (sudden, unexpected death or suicide).
Psychological well being (as defined in the individual studies)

Measures of effect

The review will categorise outcomes into those measured in the shorter term (within 12 weeks of the onset of therapy), medium term (within 13 to 26 weeks of the onset of therapy) and longer term (over 26 weeks since the onset of therapy).

Additional outcome(s)

Secondary outcomes

Mental state
Quality of life
Social functioning
Hospital readmission
Unexpected or unwanted effect (adverse effects), such as anxiety, depression and dependence on the relationship with the therapist

Data extraction (selection and coding)

Data will be extracted from papers included in the review using JBI-MAStARI. In this stage, any relevant studies will be extracted in relation to their population, interventions, study methods and outcomes.

Where data are missing or unclear, authors will be contacted to obtain information.

Risk of bias (quality) assessment

All papers selected for retrieval will be assessed by two independent reviewers for methodological validity prior to inclusion in the review.

Since the review will evaluate the experimental studies only, The Joanna Briggs Institute Meta Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI) will be used to evaluate each study’s methodological validity.

If there is a disagreement between the two reviewers, there will be a discussion with the third reviewer to solve the dissimilarity.

Strategy for data synthesis

Where possible quantitative research study results will be pooled in statistical meta-analysis using Review Manager Software from the Cochrane Collaboration.

Odds ratio (for categorical outcome data) or standardised mean differences (for continuous data) and their 95% confidence intervals will be calculated for each study.

Heterogeneity will be assessed using the standard Chi-square. Where statistical pooling is not possible the findings will be presented in narrative form.

Step 2: formulate a research question

Developing a focused research question is crucial for a systematic review, as it underpins every stage of the review process.

The question defines the review’s nature and scope, guides the identification of relevant studies, and shapes the data extraction and synthesis processes.

It’s essential that the research question is answerable and clearly stated in the review protocol, ensuring that the review’s boundaries are well-defined.

A narrow question may limit the number of relevant studies and generalizability, while a broad question can make it challenging to reach specific conclusions.

PICO Framework

The PICO framework is a model for creating focused clinical research questions. The acronym PICO stands for:

P opulation/Patient/Problem: This element defines the specific group of people the research question pertains to.
I ntervention: This is the treatment, test, or exposure being considered for the population.
C omparison: This is the alternative intervention or control group against which the intervention is being compared.
O utcome: This element specifies the results or effects of the interventions being investigated

Using the PICO format when designing research helps to minimize bias because the questions and methods of the review are formulated before reviewing any literature.

The PICO elements are also helpful in defining the inclusion criteria used to select sources for the systematic review.

The PICO framework is commonly employed in systematic reviews that primarily analyze data from randomized controlled trials .

Not every element of PICO is required for every research question. For instance, it is not always necessary to have a comparison

Types of questions that can be answered using PICO:

“In patients with a recent acute stroke (less than 6 weeks) with reduced mobility ( P ), is any specific physiotherapy approach ( I ) more beneficial than no physiotherapy ( C ) at improving independence in activities of daily living and gait speed ( O )?

“For women who have experienced domestic violence ( P ), how effective are advocacy programmes ( I ) compared to other treatments ( C ) on improving the quality of life ( O )?”

Etiology/Harm

Are women with a history of pelvic inflammatory disease (PID) ( P ) at higher risk for gynecological cancers ( O ) than women with no history of PID ( C )?

Among asymptomatic adults at low risk of colon cancer ( P ), is fecal immunochemical testing (FIT) ( I ) as sensitive and specific for diagnosing colon cancer ( O ) as colonoscopy ( C )?

Among adults with pneumonia ( P ), do those with chronic kidney disease (CKD) ( I ) have a higher mortality rate ( O ) than those without CKD ( C )?

Alternative Frameworks

PICOCS : This framework, used in public health research, adds a “ C ontext” element to the PICO framework. This is useful for examining how the environment or setting in which an intervention is delivered might influence its effectiveness.
PICOC : This framework expands on PICO by incorporating “ C osts” as an element of the research question. It is particularly relevant to research questions involving economic evaluations of interventions.
ECLIPSE : E xpectations, C lient group, L ocation, I mpact, P rofessionals involved, S ervice, and E valuation. It is a mnemonic device designed to aid in searching for health policy and management information.
PEO : This acronym, standing for P atient, E xposure, and O utcome, is a variation of PICO used when the research question focuses on the relationship between exposure to a risk factor and a specific outcome.
PIRD : This acronym stands for P opulation, I ndex Test, R eference Test, and D iagnosis of Interest, guiding research questions that focus on evaluating the diagnostic accuracy of a particular test.
PFO : This acronym, representing P opulation, P rognostic F actors, and O utcome, is tailored for research questions that aim to investigate the relationship between specific prognostic factors and a particular health outcome.
SDMO : This framework, which stands for S tudies, D ata, M ethods, and O utcomes, assists in structuring research questions focused on methodological aspects of research, examining the impact of different research methods or designs on the quality of research findings.

Step 3: Search Strategy

PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) provide appropriate guidance for reporting quantitative literature searches.

Present the full search strategies for all databases, registers and websites, including any filters and limits used. PRISMA 2020 Checklist

A search strategy is a comprehensive and reproducible plan for identifying all relevant research studies that address a specific research question.

This systematic approach to searching helps minimize bias and distinguishes systematic reviews from other types of literature reviews.

It’s important to be transparent about the search strategy and document all decisions for auditability. The goal is to identify all potentially relevant studies for consideration.

Here’s a breakdown of a search strategy:

Search String Construction

It is recommended to consult topic experts on the review team and advisory board in order to create as complete a list of search terms as possible for each concept.

To retrieve the most relevant results, a search string is used. This string is made up of:

Keywords: Search terms should be relevant to the subject areas of the research question and should be identified for all components of the research question (e.g., Population, Intervention, Comparator, and Outcomes – PICO). Using relevant keywords helps minimize irrelevant search returns. Sources such as dictionaries, textbooks, and published articles can help identify appropriate keywords.
Synonyms: These are words or phrases with similar meanings to the keywords, as authors may use different terms to describe the same concepts. Including synonyms helps cover variations in terminology and increases the chances of finding all relevant studies. For example, a drug intervention may be referred to by its generic name or by one of its several proprietary names.
Truncation symbols : These broaden the search by capturing variations of a keyword. They function by locating every word that begins with a specific root. For example, if a user was researching interventions for smoking, they might use a truncation symbol to search for “smok*” to retrieve records with the words “smoke,” “smoker,” “smoking,” or “smokes.” This can save time and effort by eliminating the need to input every variation of a word into a database.
Boolean operators: The use of Boolean operators (AND/OR/NEAR/NOT) helps to combine these terms effectively, ensuring that the search strategy is both sensitive and specific. For instance, using “AND” narrows the search to include only results containing both terms, while “OR” expands it to include results containing either term.

Information Sources

The primary goal is to find all published and unpublished studies that meet the predefined criteria of the research question. This includes considering various sources beyond typical databases

Information sources for systematic reviews can include a wide range of resources like scholarly databases, unpublished literature, conference papers, books, and even expert consultations.

Specify all databases, registers, websites, organisations, reference lists and other sources searched or consulted to identify studies. Specify the date when each source was last searched or consulted. PRISMA 2020 Checklist

An exhaustive, systematic search strategy is developed with the assistance of an expert librarian.

Electronic Databases: Searches should include seven key databases: CINAHL, Medline, APA PsycArticles, Psychology and Behavioral Sciences Collection, APA PsycInfo, SocINDEX with Full Text, and Web of Science: Core Collections.
Grey Literature: In addition to databases, forensic or ‘expansive’ searches can be conducted. This includes: conference proceedings, unpublished reports, theses, ongoing clinical trial databases, searches by names of authors of relevant publications. Independent research bodies may also be good sources of material, e.g. Centre for Research in Ethnic Relations , Joseph Rowntree Foundation , Carers UK .
Citation Searching : Reference lists often lead to highly cited and influential papers in the field, providing valuable context and background information for the review.
Handsearching: Manually searching through specific journals or conference proceedings page-by-page is another way to ensure all relevant studies are captured, particularly those not yet indexed in databases.
Contacting Experts: Reaching out to researchers or experts in the field can provide access to unpublished data or ongoing research not yet publicly available.

It is important to note that this may not be an exhaustive list of all potential databases.

A systematic computerized search was performed for publications that appeared between 1974 and 2018 in English language journals. Four databases were searched including PsychINFO, Embase, OVOID MEDLINE, and AMED. The databases were searched with combinations of search terms relating to attachment (“attachment” OR “working model” OR “safe haven” OR “secure base” OR “felt security”) AND romantic couples (“dyad” OR “couple” OR “spous” OR “partner” OR “romantic” OR “wife” OR “husband” OR “close relationship” OR “interpersonal” OR “intimate” OR “mari”) AND social support (“support prov” OR “caregiving” OR “support giv” OR “social support” OR “enacted support” OR “support received” OR “receiv* support” OR “prov support” OR “dyadic coping” OR “interpersonal coping” OR “collaborative coping” OR “help‐seeking” OR “emotional support” OR “tangible support” OR “instrumental support” OR “perceived support” OR “responsive” OR “buffer” OR “partner support” OR “Support avail*” OR “available support”). The reference lists of the retrieved studies were checked to find other relevant publications, which were not identified in the computerized database searches.

Inclusion Criteria

Specify the inclusion and exclusion criteria for the review. PRISMA 2020 Checklist

Before beginning the literature search, researchers should establish clear eligibility criteria for study inclusion.

Inclusion criteria are used to select studies for a systematic review and should be based on the study’s research method and PICO elements.

To maintain transparency and minimize bias, eligibility criteria for study inclusion should be established a priori. Ideally, researchers should aim to include only high-quality randomized controlled trials that adhere to the intention-to-treat principle.

The selection of studies should not be arbitrary, and the rationale behind inclusion and exclusion criteria should be clearly articulated in the research protocol.

When specifying the inclusion and exclusion criteria, consider the following aspects:

Intervention Characteristics: Researchers might decide that, in order to be included in the review, an intervention must have specific characteristics. They might require the intervention to last for a certain length of time, or they might determine that only interventions with a specific theoretical basis are appropriate for their review.
Population Characteristics: A systematic review might focus on the effects of an intervention for a specific population. For instance, researchers might choose to focus on studies that included only nurses or physicians.
Outcome Measures: Researchers might choose to include only studies that used outcome measures that met a specific standard.
Age of Participants: If a systematic review is examining the effects of a treatment or intervention for children, the authors of the review will likely choose to exclude any studies that did not include children in the target age range.
Diagnostic Status of Participants: Researchers conducting a systematic review of treatments for anxiety will likely exclude any studies where the participants were not diagnosed with an anxiety disorder.
Study Design: Researchers might determine that only studies that used a particular research design, such as a randomized controlled trial, will be included in the review.
Control Group: In a systematic review of an intervention, researchers might choose to include only studies that included certain types of control groups, such as a waiting list control or another type of intervention.
Publication status : Decide whether only published studies will be included or if unpublished works, such as dissertations or conference proceedings, will also be considered.

Studies that met the following criteria were included: (a) empirical studies of couples (of any gender) who are in a committed romantic relationship, whether married or not; (b) measurement of the association between adult attachment and support in the context of this relationship; (c) the article was a full report published in English; and (d) the articles were reports of empirical studies published in peer‐reviewed journals, dissertations, review papers, and conference presentations.

Iterative Process

The iterative nature of developing a search strategy for systematic reviews stems from the need to refine and adapt the search process based on the information encountered at each stage.

A single attempt rarely yields the perfect final strategy. Instead, it is an evolving process involving a series of test searches, analysis of results, and discussions among the review team.

Here’s how the iterative process unfolds:

Initial Strategy Formulation: Based on the research question, the team develops a preliminary search strategy, including identifying relevant keywords, synonyms, databases, and search limits.
Test Searches and Refinement: The initial search strategy is then tested on chosen databases. The results are reviewed for relevance, and the search strategy is refined accordingly. This might involve adding or modifying keywords, adjusting Boolean operators, or reconsidering the databases used.
Discussions and Iteration: The search results and proposed refinements are discussed within the review team. The team collaboratively decides on the best modifications to improve the search’s comprehensiveness and relevance.
Repeating the Cycle: This cycle of test searches, analysis, discussions, and refinements is repeated until the team is satisfied with the strategy’s ability to capture all relevant studies while minimizing irrelevant results.

The iterative nature of developing a search strategy is crucial for ensuring that the systematic review is comprehensive and unbiased.

By constantly refining the search strategy based on the results and feedback, researchers can be more confident that they have identified all relevant studies.

This iterative process ensures that the applied search strategy is sensitive enough to capture all relevant studies while maintaining a manageable scope.

Throughout this process, meticulous documentation of the search strategy, including any modifications, is crucial for transparency and future replication of the systematic review.

Step 4: Search the Literature

Conduct a systematic search of the literature using clearly defined search terms and databases.

Applying the search strategy involves entering the constructed search strings into the respective databases’ search interfaces. These search strings, crafted using Boolean operators, truncation symbols, wildcards, and database-specific syntax, aim to retrieve all potentially relevant studies addressing the research question.

The researcher, during this stage, interacts with the database’s features to refine the search and manage the retrieved results.

This might involve employing search filters provided by the database to focus on specific study designs, publication types, or other relevant parameters.

Applying the search strategy is not merely a mechanical process of inputting terms; it demands a thorough understanding of database functionalities and a discerning eye to adjust the search based on the nature of retrieved results.

Step 5: screening and selecting research articles

Once the search strategy is finalized, it is applied to the selected databases, yielding a set of search results.

These search results are then screened against pre-defined inclusion criteria to determine their eligibility for inclusion in the review.

The goal is to identify studies that are both relevant to the research question and of sufficient quality to contribute to a meaningful synthesis.

Studies meeting the inclusion criteria are usually saved into electronic databases, such as Endnote or Mendeley , and include title, authors, date and publication journal along with an abstract (if available).

Study Selection

Specify the methods used to decide whether a study met the inclusion criteria of the review, including how many reviewers screened each record and each report retrieved, whether they worked independently, and if applicable, details of automation tools used in the process. PRISMA 2020 Checklist

The selection process in a systematic review involves multiple reviewers to ensure rigor and reliability.

To minimize bias and enhance the reliability of the study selection process, it is recommended that at least two reviewers independently assess the eligibility of each study. This independent assessment helps reduce the impact of individual biases or errors in judgment.

Initial screening of titles and abstracts: After applying a strategy to search the literature, the next step involves screening the titles and abstracts of the identified articles against the predefined inclusion and exclusion criteria. During this initial screening, reviewers aim to identify potentially relevant studies while excluding those clearly outside the scope of the review. It is crucial to prioritize over-inclusion at this stage, meaning that reviewers should err on the side of keeping studies even if there is uncertainty about their relevance. This cautious approach helps minimize the risk of inadvertently excluding potentially valuable studies.
Retrieving and assessing full texts: For studies which a definitive decision cannot be made based on the title and abstract alone, reviewers need to obtain the full text of the articles for a comprehensive assessment against the predefined inclusion and exclusion criteria. This stage involves meticulously reviewing the full text of each potentially relevant study to determine its eligibility definitively.
Resolution of disagreements : In cases of disagreement between reviewers regarding a study’s eligibility, a predefined strategy involving consensus-building discussions or arbitration by a third reviewer should be in place to reach a final decision. This collaborative approach ensures a fair and impartial selection process, further strengthening the review’s reliability.

First, the search results from separate databases were combined, and any duplicates were removed. The lead author (S. M.) and a postgraduate researcher (F. N.) applied the described inclusion criteria in a standardized manner. First, both the titles and abstracts of the articles were evaluated for relevance. If, on the basis of the title and/or abstract, the study looked likely to meet inclusion criteria hard copies of the manuscripts were obtained. If there was doubt about the suitability of an article, then the manuscript was included in the next step. The remaining articles were obtained for full‐text review, and the method and results sections were read to examine whether the article fitted the inclusion criteria. If there was doubt about the suitability of the manuscripts during this phase, then this article was discussed with another author (C. H.). Finally, the reference lists of the eligible articles were checked for additional relevant articles not identified during the computerized search. For the selected articles (n = 43), the results regarding the relationship between attachment and support were included in this review (see Figure 1, for PRISMA flowchart).

PRISMA Flowchart

The PRISMA flowchart is a visual representation of the study selection process within a systematic review.

The flowchart illustrates the step-by-step process of screening, filtering, and selecting studies based on predefined inclusion and exclusion criteria.

The flowchart visually depicts the following stages:

Identification: The initial number of titles and abstracts identified through database searches.
Screening: The screening process, based on titles and abstracts.
Eligibility: Full-text copies of the remaining records are retrieved and assessed for eligibility.
Inclusion: Applying the predefined inclusion criteria resulted in the inclusion of publications that met all the criteria for the review.
Exclusion: The flowchart details the reasons for excluding the remaining records.

This systematic and transparent approach, as visualized in the PRISMA flowchart, ensures a robust and unbiased selection process, enhancing the reliability of the systematic review’s findings.

The flowchart serves as a visual record of the decisions made during the study selection process, allowing readers to assess the rigor and comprehensiveness of the review.

Step 6: Criticallay Appraising the Quality of Included Studies

Quality assessment provides a measure of the strength of the evidence presented in a review.

High-quality studies with rigorous methodologies contribute to a more robust and reliable evidence base, increasing confidence in the review’s conclusions.

Conversely, including low-quality studies with methodological weaknesses can undermine the review’s findings and potentially lead to inaccurate recommendations.

To judge the quality of studies included in a systematic review, standardized instruments, such as checklists and scales, are commonly used. These tools help to ensure a transparent and reproducible assessment process.

The choice of tool should be justified and aligned with the study design and the level of detail required. Using quality scores alone is discouraged; instead, individual aspects of methodological quality should be considered.

Here are some specific tools mentioned in the sources:

Jadad score
Cochrane Risk of Bias tool
Cochrane Effective Practice and Organisation of Care (EPOC) Group Risk of Bias Tool
Quality Assessment of Diagnostic Accuracy Studies (QUADAS)
Newcastle – Ottawa Quality Assessment Scale for case-control and cohort studies
EPHPP Assessment Tool
Critical Appraisal Skills Programme (CASP) Appraisal Checklist
Cochrane Public Health Group (CPHG)

The quality of the study was not an inclusion criterion; however, a study quality check was carried out. Two independent reviewers (S. M. and C. H.) rated studies that met the inclusion criteria to determine the strength of the evidence. The Effective Public Health Practice Project Quality Assessment Tool for Quantitative Studies was adapted to assess the methodological quality of each study (Thomas, Ciliska, Dobbins, & Micucci, 2004). The tool was adjusted to include domains relevant to the method of each study. For example, blinding was removed for nonexperimental studies. Following recommendations by Thomas et al. (2004) each domain was rated as either weak (3 points), moderate (2 points), or strong (1 point). The mean score across questions was used as an indicator of overall quality, and studies were assigned an overall quality rating of strong (1.00–1.50), moderate (1.51–2.50),

Evidence Tables

Aspects of the appraisal of studies included in the review should be recorded as evidence tables (NICE 2009): simple text tables where the design and scope of studies are summarised.

The reader of the review can use the evidence tables to check the details, and assess the credibility and generalisability of findings, of particular studies.

Critical appraisal of the quality of included studies may be combined with data extraction tables.

Step 7: extracting data from studies

To effectively extract data from studies that meet your systematic review’s inclusion criteria, you should follow a structured process that ensures accuracy, consistency, and minimizes bias.

1. Develop a data extraction form:

Design a standardized form (paper or electronic) to guide the data extraction process : This form should be tailored to your specific review question and the types of studies included.
Pilot test the form : Test the form on a small sample of included studies (e.g., 3-5). Assess for clarity, completeness, and usability. Refine the form based on feedback and initial experiences.
Reliability : Ensure all team members understand how to use the form consistently.

2. Extract the data:

General Information: This includes basic bibliographic details (journal, title, author, volume, page numbers), study objective as stated by the authors, study design, and funding source.
Study Characteristics: Capture details about the study population (demographics, inclusion/exclusion criteria, recruitment procedures), interventions (description, delivery methods), and comparators (description if applicable).
Outcome Data: Record the results of the intervention and how they were measured, including specific statistics used. Clearly define all outcomes for which data are being extracted.
Risk of Bias Assessment: Document the methods used to assess the quality of the included studies and any potential sources of bias. This might involve using standardized checklists or scales.
Additional Information: Depending on your review, you may need to extract data on other variables like adverse effects, economic evaluations, or specific methodological details.

3. Dual independent review:

Ensure that at least two reviewers independently extract data from each study using the standardized form. Cross-check extracted data for accuracy to minimize bias and helps identify any discrepancies.
Have a predefined strategy for resolving disagreements: This might involve discussion, consensus, or arbitration by a third reviewer.
Record the reasons for excluding any studies during the data extraction phase. :This enhances the transparency and reproducibility of your review.
If necessary, contact study authors to obtain missing or clarify unclear information : This is particularly important for data critical to your review’s outcomes.
Clearly document your entire data extraction process, including any challenges encountered and decisions made. This enhances the transparency and rigor of your systematic review.

By following these steps, you can effectively extract data from studies that meet your inclusion criteria, forming a solid foundation for the analysis and synthesis phases of your systematic review.

Step 8: synthesize the extracted data

The key element of a systematic review is the synthesis: that is the process that brings together the findings from the set of included studies in order to draw conclusions based on the body of evidence.

Data synthesis in a systematic review involves collating, combining, and summarizing findings from the included studies.

This process aims to provide a reliable and comprehensive answer to the review question by considering the strength of the evidence, examining the consistency of observed effects, and investigating any inconsistencies.

The data synthesis will be presented in the results section of the systematic review.

Develop a clear text narrative that explains the key findings
Use a logical heading structure to guide readers through your results synthesis
Ensure your text narrative addresses the review’s research questions
Use tables to summarise findings (can be same table as data extraction)

Identifying patterns, trends, and differences across studies

Narrative synthesis uses a textual approach to analyze relationships within and between studies to provide an overall assessment of the evidence’s robustness. All systematic reviews should incorporate elements of narrative synthesis, such as tables and text.

Systematic Review Data Extraction Form Patient Outcomes e1721413775469

Remember, the goal of a narrative synthesis is to go beyond simply summarizing individual studies. You’re aiming to create a new understanding by integrating and interpreting the available evidence in a systematic and transparent way.

Organize your data:

Group studies by themes, interventions, or outcomes
Create summary tables to display key information across studies
Use visual aids like concept maps to show relationships between studies

Describe the studies:

Summarize the characteristics of included studies (e.g., designs, sample sizes, settings)
Highlight similarities and differences across studies
Discuss the overall quality of the evidence

Develop a preliminary synthesis:

Start by describing the results of individual studies
Group similar findings together
Identify overarching themes or trends

Explore relationships:

Look for patterns in the data
Identify factors that might explain differences in results across studies
Consider how study characteristics relate to outcomes

Address contradictions:

Consider differences in study populations, interventions, or contexts
Look at methodological differences that might explain discrepancies
Consider the implications of inconsistent results
Don’t ignore conflicting findings
Discuss possible reasons for contradictions

Avoid vote counting:

Don’t simply tally positive versus negative results
Instead, consider the strength and quality of evidence for each finding

Assess the robustness of the synthesis:

Reflect on the strength of evidence for each finding
Consider how gaps or limitations in the primary studies affect your conclusions
Discuss any potential biases in the synthesis process

Step 9: discussion section and conclusion

Summarize key findings:.

Summarize key findings in relation to your research questions
Highlight main themes or patterns across studies
Explain the nuances and complexities in the evidence
Discuss the overall strength and consistency of the evidence
This provides a clear takeaway message for readers

Consider study quality and context:

Assess whether higher quality studies tend to show different results
Examine if findings differ based on study setting or participant characteristics
This helps readers weigh the relative importance of conflicting findings

Discuss implications:

For practice: How might professionals apply these findings?
For policy: What policy changes might be supported by the evidence?
Consider both positive and negative implications
This helps translate your findings into real-world applications

Identify gaps and future research:

Point out areas where evidence is lacking or inconsistent
Suggest specific research questions or study designs to address these gaps
This helps guide future research efforts in the field

State strengths and limitations:

Discuss the strengths of your review (e.g., comprehensive search, rigorous methodology)
Acknowledge limitations (e.g., language restrictions, potential for publication bias)
This balanced approach demonstrates critical thinking and helps readers interpret your findings

Minimizing Bias

To reduce bias in a systematic review, it is crucial to establish a systematic and transparent review process that minimizes bias at every stage. Sources provide insights into strategies and methods to achieve this goal.

Protocol development and publication: Developing a comprehensive protocol before starting the review is essential. Publishing the protocol in repositories like PROSPERO or Cochrane Library promotes transparency and helps avoid deviations from the planned approach, thereby minimizing the risk of bias.
Transparent reporting: Adhering to reporting guidelines, such as PRISMA, ensures that all essential aspects of the review are adequately documented, increasing the reader’s confidence in the transparency and completeness of systematic review reporting.
Dual independent review: Employing two or more reviewers independently at multiple stages of the review process (study selection, data extraction, quality assessment) minimizes bias. Any disagreements between reviewers should be resolved through discussion or by consulting a third reviewer. This approach reduces the impact of individual reviewers’ subjective interpretations or errors.
Rigorous quality assessment: Assessing the methodological quality of included studies is crucial for minimizing bias in the review findings. Using standardized critical appraisal tools and checklists helps identify potential biases within individual studies, such as selection bias, performance bias, attrition bias, and detection bias.
Searching beyond published literature: Explore sources of “grey literature” such as conference proceedings, unpublished reports, theses, and ongoing clinical trial databases.
Contacting experts in the field : Researchers can reach out to authors and investigators to inquire about unpublished or ongoing studies
Considering language bias : Expanding the search to include studies published in languages other than English can help reduce language bias, although this may increase the complexity and cost of the review.

Reading List

Galante, J., Galante, I., Bekkers, M. J., & Gallacher, J. (2014). Effect of kindness-based meditation on health and well-being: a systematic review and meta-analysis . Journal of consulting and clinical psychology , 82 (6), 1101.
Schneider, M., & Preckel, F. (2017). Variables associated with achievement in higher education: A systematic review of meta-analyses . Psychological bulletin , 143 (6), 565.
Murray, J., Farrington, D. P., & Sekol, I. (2012). Children’s antisocial behavior, mental health, drug use, and educational performance after parental incarceration: a systematic review and meta-analysis . Psychological bulletin , 138 (2), 175.
Roberts, B. W., Luo, J., Briley, D. A., Chow, P. I., Su, R., & Hill, P. L. (2017). A systematic review of personality trait change through intervention . Psychological bulletin , 143 (2), 117.
Chu, C., Buchman-Schmitt, J. M., Stanley, I. H., Hom, M. A., Tucker, R. P., Hagan, C. R., … & Joiner Jr, T. E. (2017). The interpersonal theory of suicide: A systematic review and meta-analysis of a decade of cross-national research. Psychological bulletin , 143 (12), 1313.
McLeod, S., Berry, K., Hodgson, C., & Wearden, A. (2020). Attachment and social support in romantic dyads: A systematic review . Journal of clinical psychology , 76 (1), 59-101.

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Please note you do not have access to teaching notes, digital financial consumers' decision-making: a systematic literature review and integrative framework.

International Journal of Bank Marketing

ISSN : 0265-2323

Article publication date: 5 July 2024

This study aims to systematically review the literature on digital consumers’ decision-making in the banking, financial services and insurance (BFSI) sector and proposes an integrative framework.

Design/methodology/approach

By combining databases such as Web of Science and Elton B. Stephens Company (EBSCO), we identified, analyzed and synthesized 53 peer-reviewed empirical articles that explore the connection between digital solutions in the BFSI sector and various phases and constructs of the consumer decision-making process. We examined the dependent variables (DVs) used to operationalize consumer decision-making, performed a thematic analysis of the papers and proposed an integrative framework.

The reviewed articles have garnered more attention from marketing researchers than from BFSI or artificial intelligence scholars, often employing traditional behavioral and experimental methodologies that have several limitations. We identified 38 DVs used to operationalize consumer decision-making, with the most frequently recurring constructs being “Intention to use,” “Utilization,” “Satisfaction,” “Perceived usefulness” and “Trust.” We propose an integrative framework that groups these DVs into three main clusters: subjects’ perceptions, user experience and adoption/usage choice. This systematic literature review highlights the increasing importance of emotion in recent decades and underscores the difficulty of establishing a framework where relationships between variables are direct and unidirectional, as traditional economic theories assume.

Originality/value

To the best of the authors’ knowledge, this is the first study to provide a comprehensive and systematic understanding of the DVs and the research methods used to study the impact of recent digital solutions on consumer decision-making in the BFSI sector. Further, a framework is proposed that can offer a new perspective for consumer research.

Systematic literature review
Artificial intelligence
Financial decision-making
Financial behavior

Barone, M. , Bussoli, C. and Fattobene, L. (2024), "Digital financial consumers' decision-making: a systematic literature review and integrative framework", International Journal of Bank Marketing , Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/IJBM-07-2023-0405

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DOI: 10.1108/jiabr-11-2023-0386
Corpus ID: 271289079

Shariah governance and Islamic banks: a systematic literature review

Mustanir Hussain Wasim , Muhammad Bilal Zafar
Published in Journal of Islamic Accounting… 18 July 2024
Business, Economics, Law

109 References

An extended review on sharia governance studies from 1985 to 2022, the effect of board of directors and sharia supervisory board on zakat funds at islamic banks in indonesia, revisiting the paradigm of sharīʿah governance of islamic financial institutions, sharī‘ah governance and sharī‘ah non-compliance risk management: a maqāsid sharī‘ah based appraisal, a systematic literature review on the role of sharia governance in improving financial performance in sharia banking, shari'ah governance quality and environmental, social and governance performance in islamic banks. a cross-country evidence, diversity of shari’ah supervisory board and the performance of islamic banks: evidence from an emerging economy of pakistan, open innovation in shariah compliance in islamic banks– does shariah supervisory board attributes matter, funding liquidity in islamic banks: does the shariah supervisory board's higher educational attainment matter, shariah supervisory board attributes and corporate risk-taking in islamic banks, related papers.

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SYSTEMATIC REVIEW article

Efficacy of 5 and 10 mg donepezil in improving cognitive function in patients with dementia: a systematic review and meta-analysis.

$Mehak Sheikh\n\n \n$

1 Faculty of Pharmaceutical Sciences (FOP), University of Central Punjab, Lahore, Pakistan
2 Qatar University Young Scientists Center (QUYSC), Qatar University, Doha, Qatar

Objective: The purpose of this study was to compare donepezil at 5 mg and 10 mg/day against a placebo to systematically evaluate its effectiveness in improving cognitive function among patients suffering from dementia at any stage.

Method: For this systematic review and meta-analysis, we looked up Medline, Scopus, Embase, Web of Science, and The Cochrane Library for articles on the efficacy of donepezil in dementia published in the past 20 years and summarized the placebo and intervention data. Initially, a total of 2,272 articles were extracted using our search query and after the inclusion and exclusion criteria set for extraction of data, 18 studies were included in this review using PRISMA flowchart. The ADAS-cog and MMSE assessment scales were used for measuring the outcomes using IBM SPSS 29.0 for the meta-analysis.

Result: The meta-analysis comprised a total of 18 RCTs (randomized controlled trials) that were randomized to receive either donepezil 5 mg/day ( n = 1,556), 10 mg/day ( n = 2050) or placebo ( n = 2,342). Meta-analysis concerning efficacy showed that donepezil at 10 mg/day significantly improved the MMSE score (g: 2.27, 95%CI: 1.25–3.29) but could not substantially reduce the ADAS-cog. At 5 mg/day donepezil, an overall slight improvement in MMSE score (Hedges’ g: 2.09, 95%CI: 0.88–3.30) was observed.

Conclusion: Both donepezil 5 mg/day and 10 mg/day doses demonstrated improved cognitive functions for patients with dementia, however results indicated that the 10 mg/day dose was more efficacious.

1 Introduction

Dementia is a neurological disorder that usually progresses over time. It is marked by cognitive impairment (language and memory) and non-cognitive alterations (psychosis and behavioral abnormalities; Jin and Liu, 2019 ; Ohno et al., 2019 ; Moreno-Morales et al., 2020 ). According to the World Health Organization (WHO) ( WHO, 2023 ), currently over 55 million individuals are affected by dementia worldwide ( WHO, 2023 ). The most prevalent form of dementia is Alzheimer’s disease (AD; Weller and Budson, 2018 ; Breijyeh and Karaman, 2020 ) responsible for about 70% of dementia cases ( Aarsland, 2020 ; WHO, 2023 ), followed by vascular dementia (VaD; Hu et al., 2022 ; Morris et al., 2022 ) constituting about 20% ( Aarsland, 2020 ) of the total cases. Whereas, mild cognitive impairment (MCI) may be considered an early-stage disease in AD as well as VaD ( Kasper et al., 2020 ) with 39.2% of cases progressing to dementia ( Bai et al., 2022 ).

AD is an irreversible and gradual impairment in memory and cognitive functions. It is believed that a decrease in acetylcholine (ACh) production and accumulation of β-amyloid (Aβ) have a major role in its pathogenesis ( Cholinesterase inhibitors as Alzheimer’s therapeutics (Review), 2019 ; Argueta et al., 2022 ). Unfortunately, AD currently lacks a disease-modifying therapy (DMT; Joe and Ringman, 2019 ; Noufi et al., 2019 ; Takramah and Asem, 2022 ) due to its complex and unclear pathophysiology i.e., genetic or environmental factors ( Zhang H, et al., 2022 ). The success rate of drug development against complete AD progression has been very low and is almost 0% against DMT ( Cummings et al., 2019 ). However, its progression can be slowed and its symptoms can be improved through pharmacotherapy but their therapeutic effects are limited too ( Joe and Ringman, 2019 ; Noufi et al., 2019 ; Takramah and Asem, 2022 ). Some studies show that physical exercise can also help improve cognitive symptoms and decrease their rate ( Cheng, 2016 ; Pisani et al., 2021 ).

Currently, three acetylcholinesterase inhibitors (AChEI; i.e., donepezil, galantamine, and rivastigmine) at any stage of AD and memantine ( Argueta et al., 2022 ) for mild to moderate AD have been authorized by FDA (US Food and Drug Administration) as symptomatic pharmacotherapies ( Howard et al., 2012 ; Grossberg et al., 2013 ; Tisher and Salardini, 2019 ). Acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) are candidate enzymes that are responsible for catabolism of ACh in the brain and therefore, acetylcholinesterase inhibitors (AChEI) are used to increase brain Ach levels by inhibiting these enzymes ( Birks and Harvey, 2018 ; Noufi et al., 2019 ) as well as inhibit Aβ aggregation ( Mezeiova et al., 2019 ). However, out of the three AChEI, donepezil has shown the most hopeful results and therefore has been the most studied drug ( Colwell et al., 2022 ) approved by the FDA in the late 20th century for mild to moderate AD ( Marucci et al., 2021 ) at doses of 5 mg/day and 10 mg/day. Donepezil is a reversible AChE inhibitor having 1,250 times greater affinity toward AChE than BuChE and an inhibitory effect toward Aβ formation at the same time. It is known to be well-tolerated with a high ability to improve cognitive deficits and global function in AD patients showing minimal side effects ( Barfejani et al., 2020 ; Marucci et al., 2021 ).

In addition, new monoclonal antibodies against amyloid-β i.e., Bapineuzumab and Solanezumab were introduced for the treatment of AD but their development was terminated by Pfizer and Johnson & Johnson in 2012 ( Perng et al., 2018 ). These drugs failed to execute any better results as compared to placebo in trials conducted at late-stage in patients with mild to moderate AD. One study conducted ( Abushouk et al., 2017 ) for Bapineuzumab and a phase 3 trial study conducted by Eli Lily ( Sperling et al., 2023 ) for Solanezumab confirmed these results. However, aducanumab (BiogenInc), another monoclonal antibody recently got approval from the FDA in 2021 for AD treatment in 20 years ( Dunn et al., 2021 ; Argueta et al., 2022 ) but is still under investigation concerning its risk–benefit evaluation. Besides this, recent studies have also suggested combination therapies effectively treating cognitive impairment. A very famous combination of donepezil and memantine has shown its effect in improving behavioral and psychological symptoms in dementia ( Guo et al., 2020 ; Rong et al., 2021 ; Yaghmaei et al., 2024 ) as well as in moderate to severe AD ( Knorz and Quante, 2022a ) by activation of glutamatergic neurons. Furthermore, according to the latest studies by ( Knorz and Quante, 2022 ), a neuroprotective agent EGb 761 has been shown to reduce concentrations of amyloid-β and AChE significantly ( Rong et al., 2021 ; Knorz and Quante, 2022 ). In addition to this, various vitamins ( Knorz and Quante, 2022 ) i.e., 25 OH vitamin D in combination with donepezil ( Ware et al., 2016 ; Rong et al., 2021 ) have demonstrated a greater response to cognition in the case of AD.

In contrast to AD, currently, there are no approved drugs for the treatment of VaD ( Patel and Holland, 2022 ) and MCI. The progress in the development of effective pharmacotherapy for VaD has been a challenge due to its not so well understood pathogenesis i.e., the relation between cerebrovascular pathology and cognitive impairment ( Lagunin et al., 2020 ). Donepezil 5 and 10 mg/day is currently the most widely used drug for the treatment of cognitive symptoms of VaD ( Tisher and Salardini, 2019 ) and MCI ( Chen et al., 2021 ). However, further study is required to determine its efficacy in the treatment of MCI ( Devanand et al., 2018 ). According to certain studies, there is currently insufficient evidence to warrant using cholinesterase inhibitors to treat MCI ( Pisani et al., 2021 ). Therefore, this meta-analysis lays the groundwork for further investigation on the efficacy of donepezil for the treatment of dementia (mainly AD, VaD, and MCI) in improving cognitive symptoms, comparing the dosages of 5 mg/day and 10 mg/day. To achieve this, the present study addresses the following research questions:

1. What are the most effective assessments to measure cognitive symptoms in dementia?

2. Among 5 mg and 10 mg donepezil doses, which one is more effective in managing cognitive symptoms in patients with dementia, as measured through systematic assessments?

For this meta-analysis, a systematic literature review approach was used following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines ( Page et al., 2021 ). These guidelines were used because of their ability to review and summarize previous studies while also highlighting areas in which more study is required.

2.1 Literature search strategy

To comprehensively cover all the available research, we searched Medline, Scopus, Embase, Web of Science, and The Cochrane Library. These databases were chosen because of their global reputation, offering an ideal blend of resources. We included studies from the past 20 years to make this study timely. Several trial searches were conducted and then in August 2023, the final search was executed. The search terminology followed was: [(“effic*” OR “saf*” OR “outcom*” OR “resul*” OR “effec*” OR “respons*”) AND (“donepezil” OR “aricept”) AND (“alzheime*” OR “dement*” OR “cognitive”) AND (“random* contro*” OR “placebo contro*”)]. The purpose of this search query was to elicit the study’s title, abstract, or keywords. Additionally, these search terms were chosen because of their frequent usage in medical research related to our topic. The search string was simplified which led to the more extensive search, producing the most publications possible. Afterward, these were narrowed down by using article-specific standards.

2.2 Inclusion and exclusion criteria

This study included all randomized, double-blind, or placebo-controlled trials randomized either as groups or individuals with both intervention and observation groups. Patients diagnosed with any type of dementia showing cognitive symptoms with no restriction to age, origin, gender, etiology, and cognitive impairment severity were considered research participants. Any intervention that compared donepezil with a placebo in patients with dementia was included in this review. In the treatment group where there were doses other than 5 mg/day or 10 mg/day were also inquired (i.e., 1 mg/day or 3 mg/day) in some studies, only doses of donepezil at 5 mg/day or 10 mg/day and the control group given placebo were considered in present study. Additionally, assessment scales for measurement of cognitive symptoms included in this meta-analysis were the Mini-Mental State Examination Scale (MMSE), and the Alzheimer’s Disease Assessment Scale-Cognitive Subscale (ADAS-cog) at both doses. For the exclusion criteria, the following were considered: (1) Studies that were originally a review, a retrospective study, a case report, or a meta-analysis were excluded; (2) Articles with incomplete, ongoing, or unavailable information were also excluded; and (3) Interventions in which either group was given cholinesterase other than donepezil or any non-pharmacological interventions (i.e., physical or cognitive therapy, music therapy, aromatherapy or physical exercise) were also excluded.

2.3 Cognition

Cognitive assessment scales are frequently used in clinical research of geriatric settings to assess the likelihood of dementia ( Mahendran et al., 2015 ). ADAS-Cog and MMSE assessment scales were used in the present study to evaluate the severity and improvement of cognitive impairment in patients.

2.3.1 ADAS-Cog

The purpose of ADAS-Cog is to quantify and track the progression of cognitive symptoms and has been a cornerstone of substantial clinical research and trials since its introduction in the 1980s ( Cogo-Moreira et al., 2021 , 2023 ). ADAS is considered more reliable and accurate than MMSE ( Kaufman et al., 2023 ). It mainly evaluates cognitive areas of memory, language, and orientation consisting of 11 tasks scoring of which is done from 0 to 70 as a single scale. Scoring is based on patient-performed tasks and observer-based evaluation and takes about 30–45 min for its completion ( Kueper et al., 2018 ).

Mini-Mental State Examination (MMSE) is the most often used screening instrument commonly used for assessing the extent of cognitive impairment in patients and takes about 7–10 min. It has a total of 30 tasks with subgroups covering memory skills, comprehension, reading, writing, and illustrating skills as well as visual construction attention ( Saczynski et al., 2015 ; Chiu et al., 2021 ; Jia et al., 2021 ; Su et al., 2021 ).

2.4 Data extraction

Relevant items were retrieved and cross-checked after one independent researcher examined the entirety of the included literature. The gathered data was then examined by a senior researcher. The following data from included trials was added: initial author, eligibility criteria, publishing year, region of research, research design, sample size, clinical group with severity, age, follow-up period, intervention (dose, duration), and methods of outcome assessments. If accessible, we documented the ITT findings.

2.5 Statistical methods

The goal of a meta-analysis is to compile the statistical data acquired from several research investigations. We used IBM SPSS 29.0 for statistical analysis of the data. When performing a meta-analysis, there is a trade-off between increasing the number of studies to boost strength as well as narrowing the selection to lower heterogeneity. For this meta-analysis, the raw data retrieved from studies was first inserted into a Microsoft Excel template created according to the design of the present study and was then entered in the form of means and standard deviations in SPSS software. This allowed SPSS to identify heterogeneity between studies using the Q test, p -value, and I 2 , which shows the proportion of overall variance caused by heterogeneity across trials ( Higgins et al., 2003 ; Ioannidis, 2008 ; DerSimonian and Laird, 2015 ). Hedges’s g was preferred in this study over Cohen’s d because it is usually used for sample sizes with significant differences and eliminates bias by a correction factor ( Hedge’s g Statistic, 2017 ; Lin and Aloe, 2021 ). I 2 ≥ 50%, p < 0.1 was regarded as substantial heterogeneity between studies, therefore heterogeneity source between them was further analyzed. Moreover, Forest Plots were made using a Forest Plot viewer to see ES distributions and identify outliers. Additionally, 95% confidence intervals were computed for the mean impact size estimate of each study to provide an accuracy metric. Egger’s regression test was utilized by visual examination of funnel plots using the trim-and-fill method to ascertain publication bias ( Egger et al., 1997 ; Duval and Tweedie, 2000 ). The resultant figure was used to calculate the number of research articles that were overlooked in the meta-analysis and their possible influence on the outcome, as well as to look into possible publication bias.

3.1 Characteristics of included studies

The search query yielded 652 hits from the Web of Science repository, 785 hits from the Scopus database, and 366 hits from the Medline database. We also searched Embase returning with 85 hits and The Cochrane Library yielding 384 hits. Using the literature search approach, a total of 2,272 articles were found. After the first search, titles and abstracts were manually reviewed, followed by an inclusion/exclusion criterion. Out of these, 18 articles met the requirements for inclusion. A total of 3,770 patients were assigned to a control group (placebo), while 5,989 patients were assigned to a treatment group (donepezil). Figure 1 illustrates the literature screening procedure whereas Table 1 lists the basic characteristics of included articles.

Figure 1 . PRISMA flow diagram of the literature selection process.

Table 1 . Basic characteristics of selected studies.

3.2 Efficacy outcomes

We conducted the MMSE and ADAS-cog tests to evaluate donepezil’s efficacy in patients with cognitive impairment We examined the impact of two commonly administered doses, i.e., 5 mg and 10 mg, on changes in the cognitive function of the patients in comparison to placebo. To more precisely assess the effectiveness of donepezil, we further divided the studies into additional subgroups.

As shown in Table 2 and Figure 2 , 14 articles ( Black et al., 2003 ; Holmes et al., 2004 ; Petersen et al., 2005 ; Román et al., 2005 ; Johannsen et al., 2006 ; Winblad et al., 2006 ; Black et al., 2007 ; Howard et al., 2007 ; Dichgans et al., 2008 ; Román et al., 2010 ; Mori et al., 2012 ; Gault et al., 2015 ; Ikeda et al., 2015 ; Ridha et al., 2018 ) reported the MMSE score change from baseline to endpoint to assess donepezil’s effectiveness in comparison to a placebo. The results of the heterogeneity test indicated a high level of heterogeneity among these studies (I 2 = 99%) and the Q-test demonstrated statistical significance (Q = 1863.61, p < 0.001), indicating that a sizable amount of the variability seems to represent true variation. Consequently, for this meta-analysis, a random effects model was used because the observed heterogeneity did not diminish when we observed different study designs i.e., DBRCT and RCT. The analysis indicated that patients undergoing donepezil treatment significantly improved their MMSE score (Hedges’ g: 2.21, 95%CI: [1.44, 2.98]) favoring intervention over the control group (see Supplementary Figure S4 ). Furthermore, the results of Egger’s test ( p = 0.010) showed the absence of publication bias in the included studies.

Table 2 . Subgroup meta-analysis of efficacy of donepezil against placebo in selected studies.

Figure 2 . Forest plot of MMSE.

Subsequently, we performed a subgroup analysis to assess the efficacy of donepezil when administered in doses of 5 mg and 10 mg. We analyzed those patients receiving donepezil 10 mg/day had a significant increase in their MMSE score (Hedges’ g: 2.27, 95%CI: [1.25,3.29]) while 5 mg/day donepezil only slightly managed to increase their MMSE score (Hedges’ g: 2.09, 95%CI: [0.88, 3.30]) as shown in Figure 2 . Next, we divided studies into further subgroups for more detailed analysis. When categorized into regions (see Supplementary Figure S1 ), it was observed that donepezil significantly led to an increase in the MMSE score (Hedges’ g: 3.39, 95%CI: [1.71, 5.07]) in studies conducted intercontinental. In terms of study duration, studies of more than 2 years showed an increase in MMSE score, while no significant difference was observed in studies of less than 2 years (Hedges’ g: 2.33, 95% CI: [1.56, 3.11], I 2 = 98.8%) indicating that study duration might be a source of heterogeneity (see Supplementary Figure S2 ). Furthermore, when analysis was performed in subgroups based on clinical groups, patients with VaD demonstrated an increase in MMSE score (Hedges’ g: 4.13, 95%CI: [3.14, 5.13], I 2 = 98.4%) whereas other clinical groups did not exhibit significant difference (see Supplementary Figure S3 ).

3.2.2 ADAS-cog

Additionally, ADAS-cog scores were also examined. As shown in Figure 3 and Table 2 , 11 articles ( Black et al., 2003 ; Holmes et al., 2004 ; Salloway et al., 2004 ; Petersen et al., 2005 ; Román et al., 2005 ; Johannsen et al., 2006 ; Dichgans et al., 2008 ; Román et al., 2010 ; Gault et al., 2015 Tune et al., 2003 ; Wilkinson et al., 2003 ) employed ADAS-cog scores to assess the effectiveness of donepezil in treating dementia. The heterogeneity test revealed a high degree of heterogeneity among the studies ( p = <0.001, Q = 2691.172, I 2 = 99.6%). When the random effects model was used for the meta-analysis, Egger’s test ( p = 0.075) revealed that publication bias was absent. The findings demonstrated that donepezil tended to lower ADAS-cog scores and enhance cognitive function in patients as compared to the control group. The studies were divided into subgroups, and ADAS-cog scores were analyzed. When categorized into regions, donepezil led to an increase in ADAS-cog scores (Hedges’ g: –5.67, 95%CI: [−8.12, −3.21]) only in studies with subjects from intercontinental locations (see Supplementary Figure S5 ). The heterogeneity test indicated a high degree of heterogeneity ( p = <0.001, Q = 145.923, I 2 = 98.9%) in these subgroups. When distinguished by the dose of donepezil (5 mg vs. 10 mg), statistically there was no substantial difference in ADAS-cog scores (Hedges’ g: -2.80, 95%CI: [−4.64, −0.96]) as shown in Figure 3 . When different clinical groups were considered, there was a substantial increase in heterogeneity ( p = <0.001, Q = 548.419, I 2 = 99%) among VaD patients compared to other clinical groups (see Supplementary Figure S7 ). Similarly, the division into RCT and DBRCT groups did not reveal a significant difference in the heterogeneity test (see Supplementary Figure S8 ).

Figure 3 . Forest plot of ADAS-cog.

3.3 Safety outcomes

In our analysis, we conducted statistics of common adverse effects observed during the trial, with 5 articles ( Black et al., 2003 ; Wilkinson et al., 2003 ; Román et al., 2005 ; Mori et al., 2012 ; Ikeda et al., 2015 ) contributing to the analysis. As depicted in Figure 4 for 5 mg/day, Figure 5 for 10 mg/day, and Table 3 . The heterogeneity test for the 10 mg/day dosage indicated significant variation among the studies ( p = <0.001, Q = 715.425, I2 = 98.9%), using the random effects model for the meta-analysis. Our findings revealed that the likelihood of experiencing adverse reactions with 10 mg/day of donepezil (RR = 1.07, 95%CI = 1.03, 1.11) was higher compared to 5 mg/day (RR = 1.03, 95%CI = 0.99, 1.07). The Egger’s test ( p = 0.219) in the case of 5 mg/day, and ( p = 0.664) in the case of 10 mg/day suggested no publication bias. Furthermore, we conducted thorough observations of adverse reactions during the trials, selecting adverse effects based on their prevalence and notable differences between the 5 mg/day and 10 mg/day doses. As presented in Table 3 , the findings revealed that the 10 mg/day treatment group had a higher risk for adverse events such as nausea/vomiting, diarrhea, anorexia, hypertension, and abnormal dreams. The differences were statistically significant across most adverse events, except for nausea where the 5 mg/day group showed slightly higher results (RR = 0.23, CI95% = 0.20, 0.27).

Figure 4 . Forest plot of ADRs at 5 mg/day.

Figure 5 . Forest plot of ADRs at 10 mg/day.

Table 3 . Meta-analysis of safety outcomes.

4 Discussion

This study was intended to ascertain the effectiveness of donepezil in cognitive impairments in doses. This meta-analysis of placebo-controlled trials revealed substantial differences between the donepezil and placebo groups based on MMSE (14 studies, 5,012 participants) and for the ADAS-Cog analysis (11 studies, 4,747 participants). A combination of comparative trials evaluating donepezil’s dose–response at 5 mg/d and 10 mg/d suggested that a higher dosage i.e., 10 mg/day of donepezil is favorable for maintaining or slowing down the progress of cognitive impairment in patients with any stage of dementia. All the patients with AD, Vad, and other cognitive impairments showed significant improvement in MMSE scores and a moderate improvement in ADAS-cog scores and thus these enhancements in cognition appear to have a positive effect on the functioning of the patients with dementia.

Our findings are similar to previous done meta-analyses studies including control vs. treatment group results; however, we did not just limit our study to only one factor. We divided our study into subgroups of duration, dose, region, clinical group, and study design to get more precise results of donepezil efficacy in patients. Previous meta-analysis has been done with either only a specific stage of dementia or its specific type, however, we selected all available studies with dementia i.e., AD, VaD, MCI, CADASIL, and DLB to expand our research, making our conclusions more reliable.

Our main focus throughout the studies was the dose effectiveness of donepezil measured by MMSE and ADAS-Cog scores. Through our results, we found out that 10 mg/day of donepezil was more effective than 5 mg/day and this is concurrent with the results of studies done by Whitehead et al. (2004) , Birks and Harvey (2018) , and Govind (2020) in case of AD. However, if compared to other treatment strategies both 5 mg and 10 mg donepezil are the most effective strategies for treatment according to results in studies ( Kobayashi et al., 2016 ; Blanco-Silvente et al., 2017 ; Zhang et al., 2020 ) in the case of AD. In the case of severe AD, MMSE scores were improved at 10 mg/day of donepezil and this result is also shown by Adlimoghaddam et al. (2018) .

Our study also revealed that in the case of MCI, giving 10 mg/day of donepezil showed significant improvement in MMSE scores but no substantial progress in ADAS-cog score and this result was in line with a study done by Zhang X. et al. (2022) . Whereas in the case of VaD, our results showed improved ADAS-cog scores, which are in line with the results of Chen et al. (2016) , however, our results showed moderate improvement in MMSE scores too which was not concurrent in the latter but was in line with the studies done by Shi et al. (2022) at dose of 10 mg. We could not conclude decisively in the case of DLB and CADSIL due to limited available research as well as very small sample sizes. However, our limited results showed no statistically significant improvement on cognitive scales. ADAS-cog scores were moderately improved, though MMSE scores did not show much improvement.

When subgroups were distinguished by geography, patients from Europe showed significantly enhanced MMSE scores. The subjects’ Asian origin rendered this distinction insignificant. However, studies performed across multiple continents and in North America alone showed moderate improvement as well. Furthermore, subgroup analyses based on clinical groups, dose, region, duration, and type of intervention could not mitigate the high level of heterogeneity among studies. This indicated that individual studies were highly likely to be the source of heterogeneity. Furthermore, one of the possible reasons for heterogeneity among 5 mg and 10 mg studies can be due to the different stages of severity in each study.

Moreover, as the results of this study and previous trials included in this review, are evidence of the fact that donepezil 10 mg/day is more efficacious than donepezil 5 mg/day, the adverse drug reactions (ADRs) of donepezil 10 mg/day, however, are more than donepezil 5 mg/day. One study suggests that ADRs associated with donepezil 10 mg/day are thought to be connected to a quick escalation up to 10 mg/day within 1 week of commencing medication, which was the usual procedure in the donepezil pivotal trials ( Doody et al., 2008 ). However, if we compare 10 mg with higher doses of donepezil, many recent studies show that higher doses, i.e., 15 mg/day up to 23 mg/day of donepezil have more serious side effects and poor safety profiles besides the fast improvement of cognitive symptoms ( Study Results, 2007 ; Hong et al., 2019 ; jia et al., 2020 ; Study Results, 2021 ; Mori et al., 2024a , b ). When discussing ADRs, similar studies and a study by Birks and Harvey (2018) suggest that 10 mg/day of donepezil shows mild to moderate ADRs commonly nausea, vomiting, diarrhea, and dizziness as compared to higher doses responsible for ADRs like bradycardia, and urinary incontinence. Given all of these findings, donepezil 10 mg/day appears to be an optimal choice for reducing cognitive problems compared to donepezil 5 mg/day and better tolerability and safety profile compared to higher doses. Although to overcome ADRs of 10 mg/day of donepezil, studies suggest that 10 mg/day of donepezil in combination therapy with agents like memantine shows similar improvement in cognitive symptoms with a better safety profile and tolerable ADRs in contrast to monotherapy of donepezil at 10 mg and higher doses ( Rong et al., 2021 ; Knorz and Quante, 2022 ).

4.1 Study strengths

This meta-analysis attempted to collate all the published RCT studies on dementia conducted according to inclusion criteria. Previous meta-analyses have opted to limit their analysis to a certain severity range, such as mild to moderate or severe. This was done with the idea that the severity of the disease may have an impact on the medication’s effectiveness. Regardless of the length of the trials or the severity of dementia in the patients, our research found very little evidence that the treatment effects varied between studies. This would corroborate our choice to incorporate all research, regardless of the degree of severity.

4.2 Study limitations

The current study has some limitations, which should be taken into account when interpreting its results. This study was intended to determine the efficacy of donepezil at standard doses; therefore, this meta-analysis excluded the studies that were conducted at higher doses of donepezil, i.e., more than 10 mg. The precision of results for dementia types other than AD and VaD was compromised. This might be due to a limited number of studies that fulfilled the inclusion criteria as well as the small size of these studies. Additionally, the present meta-analysis did not encompass unpublished research or data, which could not be made available even after the requests to the authors.

5 Conclusion

This meta-analysis suggests that as compared to placebo, commonly prescribed cholinesterase inhibitors, donepezil (5 and 10 mg/day) is effective for symptomatic treatment for patients with dementia. All studies included in this meta-analysis showed a positive impact of donepezil on stabilizing and delaying the development of cognitive impairment, with some studies showing statistical significance over others. Donepezil at both doses is efficacious, however, 10 mg/day at 24 weeks is more likely to execute the utmost gain.

Data availability statement

The original contributions presented in the study are included in the article/ Supplementary material , further inquiries can be directed to the corresponding author.

Author contributions

MS: Writing – original draft, Formal analysis, Methodology, Software. MA: Writing – review & editing, Validation.

The author(s) declare that no financial support was received for the research, authorship, and/or publication of this article.

Acknowledgments

This work was made possible through the Summer Research Internship Program 2023 organized by Qatar University Young Scientists Center (QUYSC). The authors would like to acknowledge Zubair Ahmad for his invaluable guidance, expertise, and support throughout this research.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Supplementary material

The Supplementary material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fnins.2024.1398952/full#supplementary-material

Aarsland, D. (2020). Epidemiology and pathophysiology of dementia-related psychosis. J. Clin. Psychiatry 81:27625. doi: 10.4088/JCP.AD19038BR1C

PubMed Abstract | Crossref Full Text | Google Scholar

Abushouk, A. I., Elmaraezy, A., Aglan, A., Salama, R., Fouda, S., Fouda, R., et al. (2017). Bapineuzumab for mild to moderate Alzheimer’s disease: a meta-analysis of randomized controlled trials. BMC Neurol. 17, 1–13. doi: 10.1186/S12883-017-0850-1/FIGURES/6

Crossref Full Text | Google Scholar

Adlimoghaddam, A., Neuendorff, M., Roy, B., and Albensi, B. C. (2018). A review of clinical treatment considerations of donepezil in severe Alzheimer’s disease. CNS Neurosci. Ther. 24, 876–888. doi: 10.1111/CNS.13035

Argueta, N., Notari, E., and Szigeti, K. (2022). Role of pharmacogenomics in individualizing treatment for Alzheimer’s disease. CNS Drugs 36, 365–376. doi: 10.1007/s40263-022-00915-3

Bai, W., Chen, P., Cai, H., Zhang, Q., Su, Z., Cheung, T., et al. (2022). Worldwide prevalence of mild cognitive impairment among community dwellers aged 50 years and older: a meta-analysis and systematic review of epidemiology studies. Age Ageing 51, 1–14. doi: 10.1093/AGEING/AFAC173

Barfejani, A. H., Jafarvand, M., Seyedsaadat, S. M., and Rasekhi, R. T. (2020). Donepezil in the treatment of ischemic stroke: review and future perspective. Life Sci. 263:118575. doi: 10.1016/J.LFS.2020.118575

Birks, J. S., and Harvey, R. J. (2018). Donepezil for dementia due to Alzheimer’s disease. Cochrane Database Syst. Rev. 2018:CD001190. doi: 10.1002/14651858.CD001190.pub3

Black, S. E., Doody, R., Li, H., McRae, T., Jambor, K. M., Xu, Y., et al. (2007). Donepezil preserves cognition and global function in patients with severe Alzheimer disease. Neurology 69, 459–469. doi: 10.1212/01.WNL.0000266627.96040.5A

Black, S., Román, G. C., Geldmacher, D. S., Salloway, S., Hecker, J., Burns, A., et al. (2003). Efficacy and tolerability of donepezil in vascular dementia: positive results of a 24-week, multicenter, international, randomized, placebo-controlled clinical trial. Stroke 34, 2323–2330. doi: 10.1161/01.STR.0000091396.95360.E1

Blanco-Silvente, L., Castells, X., Saez, M., Barceló, M. A., Garre-Olmo, J., Vilalta-Franch, J., et al. (2017). Discontinuation, efficacy, and safety of cholinesterase inhibitors for Alzheimer’s disease: a Meta-analysis and Meta-regression of 43 randomized clinical trials enrolling 16 106 patients. Int. J. Neuropsychopharmacol. 20, 519–528. doi: 10.1093/IJNP/PYX012

Breijyeh, Z., and Karaman, R. (2020). Comprehensive review on Alzheimer’s disease: causes and treatment. Molecules (Basel, Switzerland) 25:5789. doi: 10.3390/MOLECULES25245789

Chen, Y. X., Liang, N., Li, X. L., Yang, S. H., Wang, Y. P., and Shi, N. N. (2021). Diagnosis and treatment for mild cognitive impairment: a systematic review of clinical practice guidelines and consensus statements. Front. Neurol. 12:719849. doi: 10.3389/fneur.2021.719849

Chen, Y. D., Zhang, J., Wang, Y., Yuan, J. L., and Hu, W. L. (2016). Efficacy of cholinesterase inhibitors in vascular dementia: an updated Meta-analysis. Eur. Neurol. 75, 132–141. doi: 10.1159/000444253

Cheng, S. T. (2016). Cognitive reserve and the prevention of dementia: the role of physical and cognitive activities. Curr. Psychiatry Rep. 18, 1–12. doi: 10.1007/S11920-016-0721-2/METRICS

Chiu, E. C., Chien, T. H., and Lee, Y. C. (2021). Measurement equivalence between the original and estimated Mini-mental state examination in people with dementia. Int. J. Environ. Res. Public Health 18:7616. doi: 10.3390/IJERPH18147616

Cholinesterase inhibitors as Alzheimer’s therapeutics (Review) . (2019). Retrieved 23 October 2023, from https://www.spandidos-publications.com/10.3892/mmr.2019.10374#b5-mmr-20-02-1479

Google Scholar

Cogo-Moreira, H., Krance, S. H., Black, S. E., Herrmann, N., Lanctôt, K. L., MacIntosh, B. J., et al. (2021). Questioning the meaning of a change on the Alzheimer’s disease assessment scale–cognitive subscale (ADAS-cog): noncomparable scores and item-specific effects over time. Assessment 28, 1708–1722. doi: 10.1177/1073191120915273

Cogo-Moreira, H., Krance, S. H., Wu, C. Y., Lanctôt, K. L., Herrmann, N., Black, S. E., et al. (2023). State, trait, and accumulated features of the Alzheimer’s disease assessment scale cognitive subscale (ADAS-cog) in mild Alzheimer’s disease. Alzheimer’s and Dementia: Translational Res. Clin. Interven. 9:e12376. doi: 10.1002/TRC2.12376

Colwell, M. J., Tagomori, H., Chapman, S., Gillespie, A. L., Cowen, P. J., Harmer, C. J., et al. (2022). Pharmacological targeting of cognitive impairment in depression: recent developments and challenges in human clinical research. Transl. Psychiatry 12, 484–416. doi: 10.1038/s41398-022-02249-6

Cummings, J., Feldman, H. H., and Scheltens, P. (2019). The “rights” of precision drug development for Alzheimer’s disease. Alzheimers Res. Ther. 11, 76–14. doi: 10.1186/S13195-019-0529-5

DerSimonian, R., and Laird, N. (2015). Meta-analysis in clinical trials revisited. Contemp. Clin. Trials 45, 139–145. doi: 10.1016/J.CCT.2015.09.002

Devanand, D. P., Pelton, G. H., D’Antonio, K., Ciarleglio, A., Scodes, J., Andrews, H., et al. (2018). Donepezil treatment in patients with depression and cognitive impairment on stable antidepressant treatment: a randomized controlled trial. American J.f Geriatric Psychiatry: Official J. American Association for Geriatric Psychiatry 26, 1050–1060. doi: 10.1016/J.JAGP.2018.05.008

Dichgans, M., Markus, H. S., Salloway, S., Verkkoniemi, A., Moline, M., Wang, Q., et al. (2008). Donepezil in patients with subcortical vascular cognitive impairment: a randomised double-blind trial in CADASIL. Lancet. Neurol. 7, 310–318. doi: 10.1016/S1474-4422(08)70046-2

Doody, R. S., Corey-Bloom, J., Zhang, R., Li, H., Ieni, J., and Schindler, R. (2008). Safety and tolerability of donepezil at doses up to 20 mg/day: results from a pilot study in patients with Alzheimer’s disease. Drugs Aging 25, 163–174. doi: 10.2165/00002512-200825020-00008

Dunn, B., Stein, P., and Cavazzoni, P. (2021). Approval of Aducanumab for Alzheimer disease—the FDA’s perspective. JAMA Intern. Med. 181, 1276–1278. doi: 10.1001/JAMAINTERNMED.2021.4607

Duval, S., and Tweedie, R. (2000). Trim and fill: a simple funnel-plot–based method of testing and adjusting for publication Bias in Meta-analysis. Biometrics 56, 455–463. doi: 10.1111/J.0006-341X.2000.00455.X

Egger, M., Smith, G. D., Schneider, M., and Minder, C. (1997). Bias in meta-analysis detected by a simple, graphical test. BMJ 315, 629–634. doi: 10.1136/BMJ.315.7109.629

Gault, L. M., Ritchie, C. W., Robieson, W. Z., Pritchett, Y., Othman, A. A., and Lenz, R. A. (2015). A phase 2 randomized, controlled trial of the α7 agonist ABT-126 in mild-to-moderate Alzheimer’s dementia. Alzheimer’s & Dementia (New York) 1, 81–90. doi: 10.1016/J.TRCI.2015.06.001

Govind, N. (2020). Donepezil for dementia due to Alzheimer's disease. Br J Community Nurs 25, 148–149. doi: 10.12968/bjcn.2020.25.3.148

Grossberg, G. T., Manes, F., Allegri, R. F., Gutiérrez-Robledo, L. M., Gloger, S., Xie, L., et al. (2013). The safety, tolerability, and efficacy of once-daily memantine (28 mg): a multinational, randomized, double-blind, placebo-controlled trial in patients with moderate-to-severe Alzheimer’s disease taking cholinesterase inhibitors. CNS Drugs 27, 469–478. doi: 10.1007/S40263-013-0077-7

Guo, J., Wang, Z., Liu, R., Huang, Y., Zhang, N., and Zhang, R. (2020). Memantine, donepezil, or combination therapy—what is the best therapy for Alzheimer’s disease? A Network Meta-Analysis. Brain Behav. 10:e01831. doi: 10.1002/BRB3.1831

Hedge’s g Statistic . (2017). Retrieved 29 October 2023, from https://www.itl.nist.gov/div898/software/dataplot/refman2/auxillar/hedgeg.htm

Higgins, J. P. T., Thompson, S. G., Deeks, J. J., and Altman, D. G. (2003). Measuring inconsistency in meta-analyses. BMJ: British Medical J. 327, 557–560. doi: 10.1136/BMJ.327.7414.557

Holmes, C., Wilkinson, D., Dean, C., Vethanayagam, S., Olivieri, S., Langley, A., et al. (2004). The efficacy of donepezil in the treatment of neuropsychiatric symptoms in Alzheimer disease. Neurology 63, 214–219. doi: 10.1212/01.WNL.0000129990.32253.7B

Hong, Y. J., Han, H. J., Youn, Y. C., Park, K. W., Yang, D. W., Kim, S., et al. (2019). Safety and tolerability of donepezil 23 mg with or without intermediate dose titration in patients with Alzheimer’s disease taking donepezil 10 mg: a multicenter, randomized, open-label, parallel-design, three-arm, prospective trial. Alzheimers Res. Ther. 11:37. doi: 10.1186/S13195-019-0492-1

Howard, R. J., Juszczak, E., Ballard, C. G., Bentham, P., Brown, R. G., Bullock, R., et al. (2007). Donepezil for the treatment of agitation in Alzheimer’s disease. N. Engl. J. Med. 357, 1382–1392. doi: 10.1056/NEJMOA066583

Howard, R., McShane, R., Lindesay, J., Ritchie, C., Baldwin, A., Barber, R., et al. (2012). Donepezil and Memantine for moderate-to-severe Alzheimer’s disease. N. Engl. J. Med. 366, 893–903. doi: 10.1056/NEJMoa1106668

Hu, Y., Zhang, L., Guan, X., Hou, H., Bi, S., Liu, C., et al. (2022). Gunao-Yizhi decoction combined with donepezil for vascular dementia: a systematic review and meta-analysis. Medicine 101:E30971. doi: 10.1097/MD.0000000000030971

Ikeda, M., Mori, E., Matsuo, K., Nakagawa, M., and Kosaka, K. (2015). Donepezil for dementia with Lewy bodies: a randomized, placebo-controlled, confirmatory phase III trial. Alzheimers Res. Ther. 7:4. doi: 10.1186/S13195-014-0083-0

Ioannidis, J. P. A. (2008). Interpretation of tests of heterogeneity and bias in meta-analysis. J. Eval. Clin. Pract. 14, 951–957. doi: 10.1111/J.1365-2753.2008.00986.X

Jia, X., Wang, Z., Huang, F., Su, C., Du, W., Jiang, H., et al. (2021). A comparison of the Mini-mental state examination (MMSE) with the Montreal cognitive assessment (MoCA) for mild cognitive impairment screening in Chinese middle-aged and older population: a cross-sectional study. BMC Psychiatry 21:485. doi: 10.1186/S12888-021-03495-6

Jia, J., Wei, C., Chen, W., Jia, L., Zhou, A., Wang, F., et al. (2020). Safety and efficacy of donepezil 10 mg/day in patients with mild to moderate Alzheimer’s disease. J. Alzheimer’s Dis.: JAD 74, 199–211. doi: 10.3233/JAD-190940

Jin, B., and Liu, H. (2019). Comparative efficacy and safety of therapy for the behavioral and psychological symptoms of dementia: a systemic review and Bayesian network meta-analysis. J. Neurol. 266, 2363–2375. doi: 10.1007/s00415-019-09200-8

Joe, E., and Ringman, J. M. (2019). Cognitive symptoms of Alzheimer’s disease: clinical management and prevention. BMJ 367:l6217. doi: 10.1136/BMJ.L6217

Johannsen, P., Salmon, E., Hampel, H., Xu, Y., Richardson, S., Qvitzau, S., et al. (2006). Assessing therapeutic efficacy in a progressive disease: a study of donepezil in Alzheimer’s disease. CNS Drugs 20, 311–325. doi: 10.2165/00023210-200620040-00005

Kasper, S., Bancher, C., Eckert, A., Förstl, H., Frölich, L., Hort, J., et al. (2020). Management of mild cognitive impairment (MCI): the need for national and international guidelines. World J. Biol. Psychiatry 21, 579–594. doi: 10.1080/15622975.2019.1696473

Kaufman, D. M., Geyer, H. L., Milstein, M. J., and Rosengard, J. L. (2023). Dementia. Kaufman’s Clinical Neurol. Psychiatrists 111–158. doi: 10.1016/B978-0-323-79680-4.00007-3

Knorz, A. L., and Quante, A. (2022). Alzheimer’s disease: efficacy of mono- and combination therapy. A systematic review. J. Geriatr. Psychiatry Neurol. 35, 475–486. doi: 10.1177/08919887211044746

Kobayashi, H., Ohnishi, T., Nakagawa, R., and Yoshizawa, K. (2016). The comparative efficacy and safety of cholinesterase inhibitors in patients with mild-to-moderate Alzheimer’s disease: a Bayesian network meta-analysis. Int. J. Geriatr. Psychiatry 31, 892–904. doi: 10.1002/GPS.4405

Kueper, J. K., Speechley, M., and Montero-Odasso, M. (2018). The Alzheimer's disease assessment scale-cognitive subscale (ADAS-cog): modifications and responsiveness in pre-dementia populations. A narrative review. J. Alzheimer’s Dis. 63, 423–444. doi: 10.3233/JAD-170991

Lagunin, A. A., Ivanov, S. M., Gloriozova, T. A., Pogodin, P. V., Filimonov, D. A., Kumar, S., et al. (2020). Combined network pharmacology and virtual reverse pharmacology approaches for identification of potential targets to treat vascular dementia. Scientific Reports 10, 257–216. doi: 10.1038/s41598-019-57199-9

Lin, L., and Aloe, A. M. (2021). Evaluation of various estimators for standardized mean difference in meta-analysis. Stat. Med. 40, 403–426. doi: 10.1002/SIM.8781

Mahendran, R., Chua, J., Feng, L., Kua, E. H., and Preedy, V. R. (2015). The Mini-mental state examination and other neuropsychological assessment tools for detecting cognitive decline. Diet and Nutrit. Dementia and Cogn. Decline 1159–1174. doi: 10.1016/B978-0-12-407824-6.00109-9

Marucci, G., Buccioni, M., Ben, D. D., Lambertucci, C., Volpini, R., and Amenta, F. (2021). Efficacy of acetylcholinesterase inhibitors in Alzheimer’s disease. Neuropharmacology 190:108352. doi: 10.1016/J.NEUROPHARM.2020.108352

Mezeiova, E., Chalupova, K., Nepovimova, E., Gorecki, L., Prchal, L., Malinak, D., et al. (2019). Donepezil derivatives targeting amyloid-β Cascade in Alzheimer’s disease. Curr. Alzheimer Res. 16, 772–800. doi: 10.2174/1567205016666190228122956

Moreno-Morales, C., Calero, R., Moreno-Morales, P., and Pintado, C. (2020). Music therapy in the treatment of dementia: a systematic review and meta-analysis. Front. Med. 7, 1–11. doi: 10.3389/FMED.2020.00160/BIBTEX

Mori, E., Ikeda, M., Iseki, E., Katayama, S., Nagahama, Y., Ohdake, M., et al. (2024a). Efficacy and safety of donepezil in patients with dementia with Lewy bodies: results from a 12-week multicentre, randomised, double-blind, and placebo-controlled phase IV study. Psychogeriatrics: Official J. Japanese Psychogeriatric Society 24, 542–554. doi: 10.1111/PSYG.13091

Mori, E., Ikeda, M., and Kosaka, K. (2012). Donepezil for dementia with Lewy bodies: a randomized, placebo-controlled trial. Ann. Neurol. 72, 41–52. doi: 10.1002/ANA.23557

Mori, E., Ikeda, M., and Ohdake, M. (2024b). Donepezil for dementia with Lewy bodies: meta-analysis of multicentre, randomised, double-blind, placebo-controlled phase II, III, and, IV studies. Psychogeriatrics: Official J. Japanese Psychogeriatric Society 24, 589–596. doi: 10.1111/PSYG.13101

Morris, J. C., Chang Wong, E., and Chang Chui, H. (2022). Vascular cognitive impairment and dementia. Continuum (Minneapolis, Minn.) 28, 750–780. doi: 10.1212/CON.0000000000001124

Noufi, P., Khoury, R., Jeyakumar, S., and Grossberg, G. T. (2019). Use of cholinesterase inhibitors in non-Alzheimer’s dementias. Drugs Aging 36, 719–731. doi: 10.1007/S40266-019-00685-6

Ohno, Y., Kunisawa, N., and Shimizu, S. (2019). Antipsychotic treatment of behavioral and psychological symptoms of dementia (BPSD): management of extrapyramidal side effects. Front. Pharmacol. 10:478465. doi: 10.3389/FPHAR.2019.01045/BIBTEX

Page, M. J., McKenzie, J. E., Bossuyt, P. M., Boutron, I., Hoffmann, T. C., Mulrow, C. D., et al. (2021). The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 372:n71. doi: 10.1136/BMJ.N71

Patel, B. B., and Holland, N. W. (2022). Vascular dementia. The 5-minute clinical consult standard 2016 . 24th Edn. Wolters Kluwer Health.

Perng, C. H., Chang, Y. C., and Tzang, R. F. (2018). The treatment of cognitive dysfunction in dementia: a multiple treatments meta-analysis. Psychopharmacology 235, 1571–1580. doi: 10.1007/s00213-018-4867-y

Petersen, R. C., Thomas, R. G., Grundman, M., Bennett, D., Doody, R., Ferris, S., et al. (2005). Study questions effectiveness of Alzheimer’s drug. Nat. Rev. Drug Discov. 4:361. doi: 10.1056/NEJMOA050151/SUPPL_FILE/NEJMOA050151SA1.PDF

Pisani, S., Mueller, C., Huntley, J., Aarsland, D., and Kempton, M. J. (2021). A meta-analysis of randomised controlled trials of physical activity in people with Alzheimer’s disease and mild cognitive impairment with a comparison to donepezil. Int. J. Geriatr. Psychiatry 36, 1471–1487. doi: 10.1002/GPS.5581

Ridha, B. H., Crutch, S., Cutler, D., Frost, C., Knight, W., Barker, S., et al. (2018). A double-blind placebo-controlled cross-over clinical trial of DONepezil in posterior cortical atrophy due to underlying Alzheimer’s disease: DONIPAD study. Alzheimer’s Res. Therapy 10, 1–9. doi: 10.1186/S13195-018-0363-1/FIGURES/3

Román, G. C., Salloway, S., Black, S. E., Royall, D. R., Decarli, C., Weiner, M. W., et al. (2010). Randomized, placebo-controlled, clinical trial of donepezil in vascular dementia: differential effects by hippocampal size. Stroke 41, 1213–1221. doi: 10.1161/STROKEAHA.109.570077

Román, G. C., Wilkinson, D. G., Doody, R. S., Black, S. E., Salloway, S. P., and Schindler, R. J. (2005). Donepezil in vascular dementia: combined analysis of two large-scale clinical trials. Dement. Geriatr. Cogn. Disord. 20, 338–344. doi: 10.1159/000088494

Rong, X., Jiang, L., Qu, M., and Hassan, S. S. (2021). Enhancing therapeutic efficacy of donepezil by combined therapy: a comprehensive review. Curr. Pharm. Des. 27, 332–344. doi: 10.2174/1381612826666201023144836

Saczynski, J. S., Inouye, S. K., Guess, J., Jones, R. N., Fong, T. G., Nemeth, E., et al. (2015). The Montreal cognitive assessment (MoCA): creating a crosswalk with the Mini-mental state examination. J. Am. Geriatr. Soc. 63, 2370–2374. doi: 10.1111/JGS.13710

Salloway, S., Ferris, S., Kluger, A., Goldman, R., Griesing, T., Kumar, D., et al. (2004). Efficacy of donepezil in mild cognitive impairment. Neurology 63, 651–657. doi: 10.1212/01.WNL.0000134664.80320.92

Shi, X., Ren, G., Cui, Y., and Xu, Z. (2022). Comparative efficacy and acceptability of cholinesterase inhibitors and Memantine based on dosage in patients with vascular cognitive impairment: a network Meta-analysis. Curr. Alzheimer Res. 19, 133–145. doi: 10.2174/1567205019666220120112301

Sperling, R. A., Donohue, M. C., Raman, R., Rafii, M. S., Johnson, K., Masters, C. L., et al. (2023). Trial of Solanezumab in preclinical Alzheimer’s disease. N. Engl. J. Med. 389, 1096–1107. doi: 10.1056/NEJMoa2305032

Study Results . Comparison of 23 mg donepezil sustained release (SR) to 10 mg donepezil immediate release (IR) in patients with moderate to severe Alzheimer’s disease | ClinicalTrials.gov . (2007). Retrieved 2 June 2024, from https://clinicaltrials.gov/study/NCT00478205?cond=Dementia&term=Alzheimer%27s%20Disease&intr=Donepezil&page=3&rank=30&tab=results

Study Results . Open-label extension study of 23 mg donepezil SR in participants with moderate to severe Alzheimer’s disease | ClinicalTrials.gov . (2021). Retrieved 2 June 2024, from https://clinicaltrials.gov/study/NCT00566501?cond=Dementia&term=Alzheimer%27s%20Disease&intr=Donepezil&page=3&rank=25&tab=results#results-overview

Su, Y., Dong, J., Sun, J., Zhang, Y., Ma, S., Li, M., et al. (2021). Cognitive function assessed by Mini-mental state examination and risk of all-cause mortality: a community-based prospective cohort study. BMC Geriatr. 21, 1–10. doi: 10.1186/S12877-021-02471-9/TABLES/3

Takramah, W. K., and Asem, L. (2022). The efficacy of pharmacological interventions to improve cognitive and behavior symptoms in people with dementia: a systematic review and meta-analysis. Health Sci. Reports 5:e913. doi: 10.1002/HSR2.913

Tisher, A., and Salardini, A. (2019). A comprehensive update on treatment of dementia. Semin. Neurol. 39, 167–178. doi: 10.1055/S-0039-1683408/ID/JR180075-20/BIB

Tune, L., Tiseo, P. J., Ieni, J., Perdomo, C., Pratt, R. D., Votaw, J. R., et al. (2003). Donepezil HCl (E2020) maintains functional brain activity in patients with Alzheimer disease: results of a 24-week, double-blind, placebo-controlled study. Am. J. Geriatr. Psychiatry 11, 169–177. doi: 10.1097/00019442-200303000-00007

Ware, C., Assoun, P.-L., Cristancho, V., Djabelkhir, L., Wu, Y.-H., and Rigaud, A.-S. (2016). P4-384: donepezil and vitamin d in Alzheimer’S disease: the Donde study. Alzheimers Dement. 12, P1184–P1185. doi: 10.1016/J.JALZ.2016.07.130

Weller, J., and Budson, A. (2018). Current understanding of Alzheimer’s disease diagnosis and treatment. F1000Research 7:1161. doi: 10.12688/f1000research.14506.1

Whitehead, A., Perdomo, C., Pratt, R. D., Birks, J., Wilcock, G. K., and Evans, J. G. (2004). Donepezil for the symptomatic treatment of patients with mild to moderate Alzheimer’s disease: a meta-analysis of individual patient data from randomised controlled trials. Int. J. Geriatr. Psychiatry 19, 624–633. doi: 10.1002/GPS.1133

WHO . (2023). Dementia. Retrieved 11 October 2023, from https://www.who.int/news-room/fact-sheets/detail/dementia/?gclid=CjwKCAjwyY6pBhA9EiwAMzmfwTj8cCAWwNAL88FEQGo5lIGW0vZyKkq7O424hQCUoUa40ldL1EQ4uBoCBQcQAvD_BwE

Wilkinson, D., Doody, R., Helme, R., Taubman, K., Mintzer, J., Kertesz, A., et al. (2003). Donepezil in vascular dementia. Neurology 61, 479–486. doi: 10.1212/01.WNL.0000078943.50032.FC

Winblad, B., Kilander, L., Eriksson, S., Minthon, L., Båtsman, S., Wetterholm, A. L., et al. (2006). Donepezil in patients with severe Alzheimer’s disease: double-blind, parallel-group, placebo-controlled study. Lancet (London, England) 367, 1057–1065. doi: 10.1016/S0140-6736(06)68350-5

Yaghmaei, E., Lu, H., Ehwerhemuepha, L., Zheng, J., Danioko, S., Rezaie, A., et al. (2024). Combined use of donepezil and Memantine increases the probability of five-year survival of Alzheimer’s disease patients. Communications Med. 4, 99–98. doi: 10.1038/s43856-024-00527-6

Zhang, X., Lian, S., Zhang, Y., and Zhao, Q. (2022). Efficacy and safety of donepezil for mild cognitive impairment: a systematic review and meta-analysis. Clin. Neurol. Neurosurg. 213:107134. doi: 10.1016/J.CLINEURO.2022.107134

Zhang, T., Liu, N., Cao, H., Wei, W., Ma, L., and Li, H. (2020). Different doses of pharmacological treatments for mild to moderate Alzheimer’s disease: a bayesian network meta-analysis. Front. Pharmacol. 11:529266. doi: 10.3389/FPHAR.2020.00778/BIBTEX

Zhang, H., Peng, Y., Zhuo, L., Wang, Y., Zeng, G., Wang, S., et al. (2022). Recent advance on pleiotropic cholinesterase inhibitors bearing amyloid modulation efficacy. Eur. J. Med. Chem. 242:114695. doi: 10.1016/J.EJMECH.2022.114695

Keywords: systematic review, meta-analysis, cognition, donepezil, dementia, Alzheimer’s disease, vascular dementia, cognitive impairment

Citation: Sheikh M and Ammar M (2024) Efficacy of 5 and 10 mg donepezil in improving cognitive function in patients with dementia: a systematic review and meta-analysis. Front. Neurosci . 18:1398952. doi: 10.3389/fnins.2024.1398952

Received: 11 March 2024; Accepted: 10 July 2024; Published: 22 July 2024.

Reviewed by:

Copyright © 2024 Sheikh and Ammar. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Mehak Sheikh, [email protected] ; Mohammad Ammar, [email protected]

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

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v.8(11); 2016 Nov

How to Conduct a Systematic Review: A Narrative Literature Review

Nusrat jahan.

1 Psychiatry, Mount Sinai Chicago

Sadiq Naveed

2 Psychiatry, KVC Prairie Ridge Hospital

Muhammad Zeshan

3 Department of Psychiatry, Bronx Lebanon Hospital Icahn School of Medicine at Mount Sinai, Bronx, NY

Muhammad A Tahir

4 Psychiatry, Suny Upstate Medical University, Syracuse, NY

Systematic reviews are ranked very high in research and are considered the most valid form of medical evidence. They provide a complete summary of the current literature relevant to a research question and can be of immense use to medical professionals. Our goal with this paper is to conduct a narrative review of the literature about systematic reviews and outline the essential elements of a systematic review along with the limitations of such a review.

Introduction and background

A literature review provides an important insight into a particular scholarly topic. It compiles published research on a topic, surveys different sources of research, and critically examines these sources [ 1 ]. A literature review may be argumentative, integrative, historical, methodological, systematic, or theoretical, and these approaches may be adopted depending upon the types of analysis in a particular study [ 2 ].

Our topic of interest in this article is to understand the different steps of conducting a systematic review. Systematic reviews, according to Wright, et al., are defined as a “review of the evidence on a clearly formulated question that uses systematic and explicit methods to identify, select and critically appraise relevant primary research, and to extract and analyze data from the studies that are included in the review” [ 3 ]. A systematic review provides an unbiased assessment of these studies [ 4 ]. Such reviews emerged in the 1970s in the field of social sciences. Systematic reviews, as well as the meta-analyses of the appropriate studies, can be the best form of evidence available to clinicians [ 3 ]. The unsystematic narrative review is more likely to include only research selected by the authors, which introduces bias and, therefore, frequently lags behind and contradicts the available evidence [ 5 ].

Epidemiologist Archie Cochrane played a vital role in formulating the methodology of the systematic review [ 6 ]. Dr. Cochrane loved to study patterns of disease and how these related to the environment. In the early 1970s, he found that many decisions in health care were made without reliable, up-to-date evidence about the treatments used [ 6 ].

A systematic review may or may not include meta-analysis, depending on whether results from different studies can be combined to provide a meaningful conclusion. David Sackett defined meta-analysis as a “specific statistical strategy for assembling the results of several studies into a single estimate” [ 7 - 8 ].

While the systematic review has several advantages, it has several limitations which can affect the conclusion. Inadequate literature searches and heterogeneous studies can lead to false conclusions. Similarly, the quality of assessment is an important step in systematic reviews, and it can lead to adverse consequences if not done properly.

The purpose of this article is to understand the important steps involved in conducting a systematic review of all kinds of clinical studies. We conducted a narrative review of the literature about systematic reviews with a special focus on articles that discuss conducting reviews of randomized controlled trials. We discuss key guidelines and important terminologies and present the advantages and limitations of systematic reviews.

Narrative reviews are a discussion of important topics on a theoretical point of view, and they are considered an important educational tool in continuing medical education [ 9 ]. Narrative reviews take a less formal approach than systematic reviews in that narrative reviews do not require the presentation of the more rigorous aspects characteristic of a systematic review such as reporting methodology, search terms, databases used, and inclusion and exclusion criteria [ 9 ]. With this in mind, our narrative review will give a detailed explanation of the important steps of a systematic review.

Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) checklist

Systematic reviews are conducted based on predefined criteria and protocol. The PRISMA-P checklist, developed by Moher, et al., contains 17 items (26 including sub-items) comprising the important steps of a systematic review, including information about authors, co-authors, their mailing and email addresses, affiliations, and any new or updated version of a previous systematic review [ 9 ]. It also identifies a plan for documenting important protocol amendments, registry names, registration numbers, financial disclosures, and other support services [ 10 ]. Moher, et al. also state that methods of systematic reviews involve developing eligibility criteria and describing information sources, search strategies, study selection processes, outcomes, assessment of bias in individual studies, and data synthesis [ 10 ].

Research question

Writing a research question is the first step in conducting a systematic review and is of paramount importance as it outlines both the need and validity of systematic reviews (Nguyen, et al., unpublished data). It also increases the efficiency of the review by limiting the time and cost of identifying and obtaining relevant literature [ 11 ]. The research question should summarize the main objective of a systematic review.

An example research question might read, “How does attention-deficit/hyperactivity disorder (ADHD) affect the academic performance of middle school children in North America?” The question focuses on the type of data, analysis, and topic to be discussed (i.e., ADHD among North American middle school students). Try to avoid research questions that are too narrow or broad—they can lead to the selection of only a few studies and the ability to generalize results to any other populations may be limited. An example of a research question that is too narrow would be, “What is the prevalence of ADHD in children and adolescents in Chicago, IL?” Alternately, if the research question is too broad, it can be difficult to reach a conclusion due to poor methodology. An example of a research question that is too broad in scope would be, “What are the effects of ADHD on the functioning of children and adolescents in North America?”

Different tools that can be used to help devise a research question, depending on the type of question, are: population, intervention, comparator, and outcomes (PICO); sample, phenomenon of interest, design, evaluation, and research type (SPIDER); setting, perspective, intervention, comparison, and evaluation (SPICE); and expectation, client group, location, impact, professionals, and service (ECLIPSE).

The PICO approach is mostly used to compare different interventions with each other. It helps to formulate a research question related to prognosis, diagnosis, and therapies [ 12 ].

Scenario: A 50-year-old white woman visited her psychiatrist with a diagnosis of major depressive disorder. She was prescribed fluoxetine, which she feels has been helpful. However, she experienced some unpleasant side effects of nausea and abdominal discomfort. She has recently been told by a friend about the use of St. John’s wort in treating depression and would like to try this in treating her current depression. (Formulating research questions, unpublished data).

In the above-mentioned scenario, the sample population is a 50-year-old female with major depressive disorder; the intervention is St. John’s wort; the comparison is fluoxetine; and the outcome would be efficacy and safety. In order to see the outcome of both efficacy and safety, we will compare the efficacy and safety of both St. John’s wort and fluoxetine in a sample population for treating depression. This scenario represents an example where we can apply the PICO approach to compare two interventions.

In contrast, the SPIDER approach is focused more on study design and samples rather than populations [ 13 ]. The SPIDER approach can be used in this research question: “What is the experience of psychiatry residents attending a transgender education?” The sample is psychiatry residents; the phenomenon of interest is transgender education; the design is a survey; the evaluation looks at the experience; and the research type is qualitative.

The SPICE approach can be used to evaluate the outcome of a service, intervention, or project [ 14 ]. The SPICE approach applies to the following research question: “In psychiatry clinics, does the combined use of selective serotonin reuptake inhibitor (SSRI) and psychotherapy reduce depression in an outpatient clinic versus SSRI therapy alone?” The setting is the psychiatry clinic; the perspective/population is the outpatient; the intervention is combined psychotherapy and SSRI; the comparison is SSRI alone; and the evaluation is reduced depression.

The ECLIPSE approach is useful for evaluating the outcome of a policy or service (Nguyen, et al., unpublished data). ECLIPSE can apply in the following research question: “How can a resident get access to medical records of patients admitted to inpatient from other hospitals?” The expectation is: “What are you looking to improve/change to increase access to medical records for patients admitted to inpatient?” The client group is the residents; the location is the inpatient setting; the impact would be the residents having easy access to medical records from other hospitals; and the professionals in this scenario would be those involved in improving the service experiences such as hospital administrators and IT staff.

Inclusion and exclusion criteria

Establishing inclusion and exclusion criteria come after formulating research questions. The concept of inclusion and exclusion of data in a systematic review provides a basis on which the reviewer draws valid and reliable conclusions regarding the effect of the intervention for the disorder under consideration [ 11 ]. Inclusions and exclusion are based on preset criteria for specific systematic review. It should be done before starting the literature search in order to minimize the possibility of bias.

Eligibility criteria provide the boundaries of the systematic review [ 15 ]. Participants, interventions, and comparison of a research question provide the basis for eligibility criteria [ 15 ]. The inclusion criteria should be able to identify the studies of interest and, if the inclusion criteria are too broad or too narrow, it can lead to an ineffective screening process.

Protocol registration

Developing and registering research protocol is another important step of conducting a systematic review. The research protocol ensures that a systematic review is carefully planned and explicitly documented before the review starts, thus promoting consistency in conduct for the review team and supporting the accountability, research integrity, and transparency of the eventually completed review [ 10 ]. PROSPERO and the Cochrane Database of Systematic Reviews are utilized for registering research protocols and research questions, and they check for prior existing duplicate protocols or research questions. PROSPERO is an international database of prospectively registered systematic reviews related to health care and social sciences (PRISMA, 2016). It is funded by the National Institute for Health Research. The Cochrane Collaboration concentrates on producing systematic reviews of interventions and diagnostic test accuracy but does not currently produce reviews on questions of prognosis or etiology [ 16 ].

A detailed and extensive search strategy is important for the systematic review since it minimizes bias in the review process [ 17 ].

Selecting and searching appropriate electronic databases is determined by the topic of interest. Important databases are: MEDLARS Online (MEDLINE), which is the online counterpart to the Medical Literature Analysis and Retrieval System (MEDLARS); Excerpta Medica Database (EMBASE); and Google Scholar. There are multiple electronic databases available based on the area of interest. Other important databases include: PsycINFO for psychology and psychiatry; Allied and Complementary Medicine Database (AMED) for complementary medicine; Manual, Alternative, and Natural Therapy Index System (MANTIS) for alternative medical literature; and Cumulative Index to Nursing and Allied Health Literature (CINAHL) for nursing and allied health [ 15 ].

Additional studies relevant for the review may be found by looking at the references of studies identified by different databases [ 15 ]. Non-indexed articles may be found by searching the content of journals, conferences proceedings, and abstracts. It will also help with letters and commentaries which may not get indexed [ 15 ]. Reviewing clinical trial registries can provide information about any ongoing trials or unpublished research [ 15 ]. A gray literature search can access unpublished papers, reports, and conference reports, and it generally covers studies that are published in an informal fashion, rather than in an indexed journal [ 15 ]. Further search can be performed by selecting important key articles and going through in-text citations [ 15 ].

Using Boolean operators, truncation, and wildcards

Boolean operators use the relationship between different search words to help with the search strategy. These are simple words (i.e., AND, OR, and NOT) which can help with more focused and productive results (poster, Jahan, et al.: How to conduct a systematic review. APPNA 39th Summer Convention. Washington, DC. 2016). The Boolean operator AND finds articles with all the search words. The use of OR broadens the focus of the search, and it will include articles with at least one search term. The researchers can also ignore certain results from the records by using NOT in the search strategy.

An example of AND would be using “depression” AND “children” in the search strategy with the goal of studying depression in children. This search strategy will include all the articles about both depression and children. The researchers may use OR if the emphasis of the study is mood disorders or affective disorders in adolescents. In that case, the search strategy will be “mood disorders” OR “affective disorders” AND “adolescents.” This search will find all the articles about mood disorders or affective disorders in adolescents. The researchers can use NOT if they only want to study depression in children and want to ignore bipolar disorder from the search. An example search in this scenario would be “depression” NOT “bipolar disorder” AND “children.” This will help ignore studies related to bipolar disorder in children.

Truncation and wildcards are other tools to make search strategy more comprehensive and focused. While the researchers search a database for certain articles, they frequently face terminologies that have the same initial root of a word but different endings. An example would be "autism," "autistic," and "autism spectrum disorder." These words have a similar initial root derived from “autis” but they end differently in each case. The truncation symbol (*) retrieves articles that contain words beginning with “autis” plus any additional characters. Wildcards are used for words with the same meanings but different spellings due to various reasons. For the words with spelling variations of a single letter, wildcard symbols can be used. When the researcher inputs “M+N” in the search bar, this returns results containing both “man” or “men” as the wildcard accounts for the spelling variations between the letters M and N.

Study selection

Study selection should be performed in a systematic manner, so reviewers deal with fewer errors and a lower risk of bias (online course, Li T, Dickersin K: Introduction to systematic review and meta-analysis. 2016. https://www.coursera.org/learn/systematic-review #). Study selection should involve two independent reviewers who select studies using inclusion and exclusion criteria. Any disagreements during this process should be resolved by discussion or by a third reviewer [ 10 ]. Specific study types can be selected depending on the research question. For example, questions on incidence and prevalence can be answered by surveys and cohort studies. Clinical trials can provide answers to questions related to therapy and screening. Queries regarding diagnostic accuracy can be answered by clinical trials and cross-sectional studies (online course, Li T, Dickersin K: Introduction to systematic review and meta-analysis. 2016. https://www.coursera.org/learn/systematic-review #). Prognosis and harm-related questions should use cohort studies and clinical trials, and etiology questions should use case-control and cohort studies (online course, Li T, Dickersin K: Introduction to systematic review and meta-analysis. 2016. https://www.coursera.org/learn/systematic-review #).

Data screening and data extractions are two of the major steps in conducting a systematic review [ 18 ]. Data screening involves searching for relevant articles in different databases using keywords. The next step of data screening is manuscript selection by reviewing each manuscript in the search results to compare that manuscript against the inclusion criteria [ 18 ]. The researchers should also review the references of the papers selected before selecting the final paper, which is the last step of data screening [ 18 ].

The next stage is extracting and appraising the data of the included articles [ 18 ]. A data extraction form should be used to help reduce the number of errors, and more than one person should record the data [ 17 ]. Data should be collected on specific points like population type, study authors, agency, study design, humanitarian crisis, target age groups, research strengths from the literature, setting, study country, type(s) of public health intervention, and health outcome(s) addressed by the public health intervention. All this information should then be put into an electronic database [ 18 ].

Assessing bias

Bias is a systematic error (or deviation from the truth) in results or inferences. Biases can change the results of any study and lead to an underestimation or overestimation of the true intervention effect [ 19 ]. Biases can impact any aspect of a review, including selecting studies, collecting and extracting data, and making a conclusion. Biases can vary in magnitude; some are small, with negligible effect, but some are substantial to a degree where an apparent finding may be entirely due to bias [ 19 ]. There are different types of bias, including, but not limited to, selection, detection, attrition, reporting, and performance.

Selection bias occurs when a sample selected is not representative of the whole general population. If randomization of the sample is done correctly, then chances of selection bias can be minimized [ 20 ].

Detection bias refers to systematic differences between groups in how outcomes are determined. This type of bias is based on knowledge of the intervention provided and its outcome [ 19 ].

Attrition bias refers to systematic differences between groups in withdrawals from a study [ 19 ]. The data will be considered incomplete if some subjects are withdrawn or have irregular visits during data collection.

Reporting bias refers to systematic differences between reported and unreported findings, and it is commonly seen during article reviews. Reporting bias is based on reviewer judgment about the outcome of selected articles [ 20 ].

Performance bias develops due to the knowledge of the allocated interventions by participants and personnel during the study [ 20 ]. Using a double-blind study design helps prevent performance bias, where neither the experimenter nor the subjects know which group contains controls and which group contains the test article [ 14 ].

Last step of systematic review: discussion

The discussion of a systematic review is where a summary of the available evidence for different outcomes is written and discussed [ 10 ]. The limitations of a systematic review are also discussed in detail. Finally, a conclusion is drawn after evaluating the results and considering limitations [ 10 ].

Discussion of the current article

Systematic reviews with or without a meta-analysis are currently ranked to be the best available evidence in the hierarchy of evidence-based practice [ 21 ]. We have discussed the methodology of a systematic review. A systematic review is classified in the category of filtered information because it appraises the quality of the study and its application in the field of medicine [ 21 ]. However, there are some limitations of the systematic review, as we mentioned earlier in our article. A large randomized controlled trial may provide a better conclusion than a systematic review of many smaller trials due to their larger sample sizes [ 22 ], which help the researchers generalize their conclusions for a bigger population. Other important factors to consider include higher dropout rates in large studies, co-interventions, and heterogeneity among studies included in the review.

As we discussed the limitations of the systematic review and its effect on quality of evidence, there are several tools to rate the evidence, such as the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system [ 22 ]. GRADE provides a structured approach to evaluating the risk of bias, serious inconsistency between studies, indirectness, imprecision of the results, and publication bias [ 22 ]. Another approach used to rate the quality of evidence is a measurement tool to assess systematic reviews (AMSTAR) [ 23 ]. It is also available in several languages [ 23 ].

Conclusions

Despite its limitations, a systematic review can add to the knowledge of the scientific community especially when there are gaps in the existing knowledge. However, conducting a systematic review requires different steps that involve different tools and strategies. It can be difficult at times to access and utilize these resources. A researcher can understand and strategize a systematic review following the different steps outlined in this literature review. However, conducting a systematic review requires a thorough understanding of all the concepts and tools involved, which is an extensive endeavor to be summed up in one article.

The Cochrane Handbook for Systematic Reviews of Interventions and the Center for Reviews and Dissemination (CRD) provide excellent guidance through their insightful and detailed guidelines. We recommend consulting these resources for further guidance.

Given that our article is a narrative review of the scholarly literature, it contains the same limitations as noted for any narrative review. We hope that our review of the means and methods for conducting a systematic review will be helpful in providing basic knowledge to utilize the resources available to the scientific community.

The content published in Cureus is the result of clinical experience and/or research by independent individuals or organizations. Cureus is not responsible for the scientific accuracy or reliability of data or conclusions published herein. All content published within Cureus is intended only for educational, research and reference purposes. Additionally, articles published within Cureus should not be deemed a suitable substitute for the advice of a qualified health care professional. Do not disregard or avoid professional medical advice due to content published within Cureus.

The authors have declared that no competing interests exist.

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Systematic Review | Definition, Example & Guide

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Step 1: Formulate a research question

Step 2: Develop a protocol

Step 3: Search for all relevant studies

Step 4: Apply the selection criteria

Step 5: Extract the data

Step 6: Synthesize the data

Step 7: Write and publish a report

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