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3.4: Reporting findings from systematic reviews

  • Page ID
    • Peter G. Smith, Richard H. Morrow, and David A. Ross
    • London School of Hygiene & Tropical Medicine & The Johns Hopkins Bloomberg School of Public Health via Oxford University Press
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    There are several guidelines for reporting results of a systematic review. The most recent are the PRISMA guidelines (<>) which are given in Table 3.4 (Moher et al., 2009). These include a full description of the rationale for the review, the research question, methods used, and analyses. Reviewers will then need to summarize their main findings, including the strengths and limitations of the review, the strength of the evidence for each main outcome, and the relevance to different population groups.

    Finally, the results of the systematic review need to be assessed for their implications for policy and future research. One system to assist with interpreting results of systematic reviews is the GRADE system (Grading of Recommendations Assessment, Development, and Evaluation) (Guyatt et al., 2008). This gives guidelines as to whether results from a systematic review provide ‘strong’ or ‘weak’ evidence. This includes not only results of a systematic review, but also an evaluation of the balance between desirable and undesirable effects, and whether the intervention represents a wise use of resources.

    Table 3.4 PRISMA guidelines for systematic reviews and meta-analyses

    Section/topic # Checklist item Reported on page #
    Title 1 Identify the report as a systematic review, meta-analysis, or both  
    Structured summary 2 Provide a structured summary, including, as applicable: background; objectives; data sources; study eligibility criteria, participants, and interventions; study appraisal and synthesis methods; results; limitations; conclusions and implications of key findings; systematic review registration number  
    Rationale 3 Describe the rationale for the review in the context of what is already known  
    Objectives 4 Provide an explicit statement of questions being addressed with reference to participants, interventions, comparisons, outcomes, and study design (PICOS)  
    Protocol and registration 5 Indicate if a review protocol exists, if and where it can be accessed (for example, Web address), and, if available, provide registration information, including registration number  
    Eligibility criteria 6 Specify study characteristics (for example, PICOS, length of follow-up) and report characteristics (for example, years considered, language, publication status) used as criteria for eligibility, giving rationale  
    Information sources 7 Describe all information sources (for example, databases with dates of coverage, contact with study authors to identify additional studies) in the search and date last searched  
    Search 8 Present full electronic search strategy for at least one database, including any limits used, such that it could be repeated  
    Study selection 9 State the process for selecting studies (i.e. screening, eligibility, included in systematic review, and, if applicable, included in the meta-analysis)  
    Data collection process 10 Describe method of data extraction from reports (for example, piloted forms, independently, in duplicate) and any processes for obtaining and confirming data from investigators  
    Data items 11 List and define all variables for which data were sought (for example, PICOS, funding sources) and any assumptions and simplifications made  
    Risk of bias in individual studies 12 Describe methods used for assessing risk of bias of individual studies (including specification of whether this was done at the study or outcome level) and how this information is to be used in any data synthesis  
    Summary measures 13 State the principal summary measures (for example, risk ratio, difference in means)  
    Synthesis of results 14 Describe the methods of handling data and combining results of studies, if done, including measures of consistency (for example, I2) for each meta-analysis  
    Risk of bias across studies 15 Specify any assessment of risk of bias that may affect the cumulative evidence (for example, publication bias, selective reporting within studies)  
    Additional analyses 16 Describe methods of additional analyses (for example, sensitivity or subgroup analyses, meta-regression), if done, indicating which were pre-specified  
    Study selection 17 Give numbers of studies screened, assessed for eligibility, and included in the review, with reasons for exclusions at each stage, ideally with a flow diagram  
    Study characteristics 18 For each study, present characteristics for which data were extracted (for example, study size, PICOS, follow-up period), and provide the citations  
    Risk of bias within studies 19 Present data on risk of bias of each study and, if available, any outcome level assessment (see item 12)  
    Results of individual studies 20 For all outcomes considered (benefits or harms), present, for each study: (a) simple summary data for each intervention group, (b) effect estimates and confidence intervals, ideally with a forest plot  
    Synthesis of results 21 Present results of each meta-analysis done, including confidence intervals and measures of consistency  
    Risk of bias across studies 22 Present results of any assessment of risk of bias across studies (see item 15)  
    Additional analysis 23 Give results of additional analyses, if done (for example, sensitivity or subgroup analyses, meta-regression) (see item 16)  
    Summary of evidence 24 Summarize the main findings, including the strength of evidence for each main outcome; consider their relevance to key groups (for example, health care providers, users, and policy makers)  
    Limitations 25 Discuss limitations at study and outcome level (for example, risk of bias) and at review level (for example, incomplete retrieval of identified research, reporting bias)  
    Conclusions 26 Provide a general interpretation of the results, in the context of other evidence, and implications for future research  
    Funding 27 Describe sources of funding for the systematic review and other support (for example, supply of data); role of funders for the systematic review

    From Moher et al., Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement, PLoS Medicine, Volume 6, Issue 7, e1000097, Copyright © Moher et al. 2009. This table is reproduced from an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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