M Gotzsche Here is a more detailed description of the systematic review process. There are two major factors that need to be evaluated before a decision about meta-analysis is made; one is heterogeneity between studies and the other is the existence of reporting bias. Ikeda AC Assess quality of studies – helps to identify risks of bias in studies. Dechartres L Decide on a Topic Area to Discuss. Murad Synthesise study results – if the included studies are similar, the author can determine the overall effectiveness of an intervention using meta-analysis (see below); if the studies are not very similar (e.g. . JP R esearch in the health sciences has provided all health care professions, including nurs-ing, with much new knowledge to inform the prevention of illness and the care of people with ill health or trauma. All rights reserved. Systematic reviews are a type of evidence synthesis which formulate research questions that are broad or narrow in scope, and identify and synthesize data that directly relate to the systematic review question. . 12,13 Although a random-effects meta-analysis can account for some heterogeneity, when significant heterogeneity exists, meta-analysis should not be performed. A systematic review (SR) aims to retrieve, synthesize, and appraise existing knowledge on a particular subject. Resources and time will influence what level of review you can complete. A systematic review usually involves more than one person in order to increase the objectivity and trustworthiness of the reviews methods and findings. RM PROSPERO) 6, Be circumspect when interpreting the results; acknowledge the sources of bias; and consider heterogeneity, generalizability, and contemporary clinical relevance, Report the study in such a way as to allow reproducibility of the results (PRISMA) 5 or future updating of the systematic review. The systematic review process is a powerful way to extract actionable information from documents. "Bariatric surgery: a systematic review and meta-analysis." Møller MH . Ioannidis Sedgwick 15 Appropriate selection of treatment effects or risk estimates, and decisions regarding the use of fixed-effect or random-effects meta-analysis, and the software used, 16 are important. Primary and secondary outcome measures A broad range of patient safety … Cochrane reviews are often published in a paper journal as a co-publication. Key Concepts addressed: 2-11 All fair comparisons and outcomes should be reported; Details. The amount of heterogeneity can be quantified using the I2 statistic. JP Reporting bias is bias across trials. Higgins Jama 292.14 (2004): 1724-1737. The value and credibility of an SR depends on the importance of the question, the quality of the original studies, the efforts undertaken to minimize bias, and the clinical applicability. Combines strengths of critical review with a comprehensive search process. Shea It is vital that you discuss with your supervisor exactly what they expect you to do. Meta-analysis should be performed only when appropriate. Search for other works by this author on: How to read a systematic review and meta-analysis and apply the results to patient care: users’ guides to the medical literature, Clinical relevance in anesthesia journals, Characteristics of meta-analyses related to acceptance for publication in a medical journal, Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement, A third of systematic reviews changed or did not specify the primary outcome: a PROSPERO register study, Bias due to selective inclusion and reporting of outcomes and analyses in systematic reviews of randomised trials of healthcare interventions, Finding What Works in Health Care: Standards for Systematic Reviews, The Cochrane Collaboration's tool for assessing risk of bias in randomised trials, AMSTAR is a reliable and valid measurement tool to assess the methodological quality of systematic reviews, How to read a forest plot in a meta-analysis, Funnel plots for detecting bias in meta-analysis: guidelines on choice of axis, A basic introduction to fixed-effect and random-effects models for meta-analysis, Influence of trial sample size on treatment effect estimates: meta-epidemiological study, A systematic comparison of software dedicated to meta-analysis of causal studies, © The Author 2016. M A systematic review is a type of systematic review that is focused on a particular research question. 10 Careful consideration must precede the performance of the meta-analysis in the review. . . C A systematic review may or may not include a meta-analysis, which is a quantitative summary of the results. Thompson What is the contemporary relevance of the study question? LV Although the printed version of the Cochrane reviews in most instances will be shorter and more digestible, the overall methodology and the results and conclusion must remain the same. Systematic reviews are a type of review that uses repeatable analytical methods to collect secondary data and analyse it. This article aims to guide you on the different kinds of systematic review, the standard procedures to be followed, and the best approach to conducting and writing a systematic review. Setting up the criteria, searching for the information, and evaluating the information found, gives the reviewer and extremely strong understanding of the process needed to create a review as well as how to evaluate its various elements. . D In conclusion, SRs and meta-analyses synthesize and update knowledge on a topic of interest. What makes a good systematic review from Oxford University’s Centre for Evidence-Based Intervention? This guide describes how to plan, conduct, organize, and present a systematic review of quantitative (meta-analysis) or qualitative (narrative review, meta-synthesis) information. J Systematic review. The most common databases to search are PubMed (Medline), Cochrane Library CENTRAL, Embase, Cinahl, and LiLacs. Egger Participants A wide range of demographic groups and age groups. Lastly, a systematic review helps in understanding the bottom-line of lengthy literature. A systematic review (SR) is a synthesis of original research studies that uses a structured, rigorous, and reproducible methodology for summarizing the results of many studies into one coherent and practical source of recommendations for evidence-based practice. Many of the scholars approached have voiced concerns about the risk of such endeavors, due to the lack of alternative outlets for these types of papers. Before even starting the process of performing an SR, the authors should clarify their clinical question using the PICO (participants, intervention, comparison, and outcomes) approach. For the inexperienced, the PRISMA guidelines 5 can be useful, and in any case, it is strongly recommended that the conduct and reporting of the SR be in accordance with its principles. A multidisciplinary social science centre for research and teaching. You may … Are the findings novel? 11 Heterogeneity can also be evaluated visually, by inspecting a forest plot. Seems like a no-brainer, right? Published by Oxford University Press on behalf of the British Journal of Anaesthesia. JE The systematic review is a scientific tool that can help with this difficult task. P S After selection, the papers must be screened for bias. Systematic review automation technologies. This is most often done in order to reach a broader audience. JJ Note the iterative nature of the process (arrows on the left). Systematic reviews are used mainly because the review of existing studies is often more convenient than conducting a new study. Hamel The participants are the group of patients to be included. Ravaud The value of any SR depends heavily on the quantity, quality, and heterogeneity of the included studies, yet a good meta-analysis methodology is at least as important. BJ Is there a need to inform the design and conduct of a definitive, large trial? References  Buchwald, Henry, et al. For full access to this pdf, sign in to an existing account, or purchase an annual subscription. Not all public health problems can be studied using blinded clinical trials, so most evidence for public health interventions is likely to be found in other kinds of studies or, on occasions, in qualitative studies. . The first thing you'll need to do before you can create your literature review is make sure you know what topic you're going to be working with. Define the research question clearly and completely, Check that the research question is unresolved, Include an experienced meta-analyst, content expert (ideally, a triallist), and statistician, Write a detailed study protocol outlining end points, inclusion criteria, and a search strategy, and publish it in advance on a publically available website (e.g. Setting A wide range of settings within primary and secondary care including hospitals and primary care centres. Yu Altman AM Tricco In nutritional Examples include diagnostic reviews, prognostic reviews, and qualitative reviews. Page Stroup What is an effect size and what does it mean? Key elements to increase chances of acceptance include a clear and detailed methodology, with a focus on generalizability and reproducibility. There needs to be a nominated primary end point in any trial, including SRs. JP The main purpose of this type of research is to identify, review, and summarize the best available research on a specific research question. Hedges DF Wells Tetzlaff Kirkham Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist will help to include all essential elements ( http://www.prisma-statement.org/PRISMAStatement/PRISMAStatement.aspx ). Meta-analysis is the statistical method used to combine results from the relevant studies, and the resultant larger sample size provides greater reliability (precision) of the estimates of any treatment effect. 5 A good SR also includes a comprehensive and critical discussion of the results, including strengths and limitations, such as assessment of bias, heterogeneity, and used definitions and categorizations. 1 Clinical decisions should be based on the totality of the best evidence and not the results of individual studies. Has the question been adequately addressed by a previous systematic review (and how recently)? Therefore, we … et al. Seeks to systematically search for, appraise and synthesis research evidence, often adhering to guidelines on the conduct of a review . Ideally, the importance of the study is highlighted, considering clinical usefulness and the need for future research (Table 1 ). Design Systematic review. Recently, however many other types of SRs are being done that may not necessarily fit this formula. 6 There is no fixed limit for secondary outcomes, but normally five to nine will be considered a maximum. . The clinical question should be described in detail at the protocol stage. A document often written by a panel that provides a comprehensive review of all relevant studies on a particular clinical or health-related topic/question. Thacker In the health fields, performing and then publishing these reviews … A The last of these, ideally, should have led at least one of the clinical trials being included in the analysis. Randomized Control Trials (RCT) An epidemiological experiment in which subjects in a population are randomly allocated into groups, usually called study and control groups, to receive or not receive an experimental preventive or therapeutic procedure, manoeuvre, or intervention. 13 Likewise, small trial bias occurs because small trials tend to overestimate treatment effects, and these typically populate SRs in anaesthesia heavily. J The search strategy is part of the review methodology, although for some journals it can be described as supplementary material on the journal website. Make sure the sources you use are credible, and make sure you read any landmark studies and major theories in your field of research. Rothstein The PICO is useful when designing the search strategy for the review. The SR protocol should be published before starting the review process. The author team for an SR should include at least one person with some experience in the performance of SRs, one person skilled in statistics, and one person with content knowledge of the topic being addressed. Meta-analysis is the statistical method used to combine results from the relevant studies, and the resultant larger sample size provides greater reliability (precision) of the estimates of any treatment effect. The Systematic Review: An Overview Synthesizing research evidence to inform nursing practice. 14. Higgins Of course the more studies you include the stronger the SR/MA. JA Page It arises when the result of a trial has an impact on the publications process. Trinquart Reporting bias will therefore almost always tend to overestimate the treatment effect of an intervention. A. M. Møller, P. S. Myles, What makes a good systematic review and meta-analysis?, BJA: British Journal of Anaesthesia, Volume 117, Issue 4, October 2016, Pages 428–430, https://doi.org/10.1093/bja/aew264, A systematic review (SR) aims to retrieve, synthesize, and appraise existing knowledge on a particular subject. SG 1. L For Permissions, please email: firstname.lastname@example.org, Radiation Effects Research Foundation Library, http://www.prisma-statement.org/PRISMAStatement/PRISMAStatement.aspx, Copyright © 2020 The British Journal of Anaesthesia Ltd. Creating a systematic review gives the reviewer an opportunity to further the discussion on a topic. GA Deeks P A Higgins SB Moher Yes you can perform a systematic review and a meta-analysis on 3 studies. Systematic reviews are regarded as the best source of research evidence. Systematic search and review. N Study quality was assessed using the Oxford Levels of Evidence proforma. Conducting a systematic review, although it does involve a series of steps, is not a linear process. Double-data extraction by two independently working researchers is recommended to prevent errors. 8 The papers need to fulfil inclusion criteria, specified in the methods section of the review. Liberati Borenstein The systematic review is created after reviewing and combining all the information from both published and unpublished studies (focusing on clinical trials of similar treatments) and then summarizing the findings. DG Group It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide, This PDF is available to Subscribers Only. Lauritsen “The systematic review is a short-cut for those who want to keep up on the latest research but can’t regularly comb through journals and databases,” he explains. MJ Most tools have been developed to extract trials data, but there are … 7. If you are in your first year, get your literature review done quickly so you can move on with your own work, and don't let it hold you back.It takes time to figure out what makes a good paper and what makes a bad one, and that comes with the experience of carrying out research, talking to other researchers and just reading more. This editorial has been written in order to help authors and readers understand the basic features of the SR and improve their ability to write and read them critically. The review process will start by retrieving and selecting relevant papers for inclusion as described in the protocol. Olson You can find out how many times an article has been cited on Google Scholar – a high citation count means the article has been influential in the field, and should certainly be included in your literature review. MJ Every paper must be evaluated to determine whether it meets the inclusion criteria. et al. 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