Article type
Year
Abstract
Background: Overviews of reviews, previously called "umbrella reviews", are now indexed in the Cochrane Database of Systematic Reviews. Overviews compile information from multiple systematic reviews (SRs) to provide a single synthesis of relevant evidence for decision-making. The Child Health Field has produced and published overviews regularly since 2006.
Objectives: To summarize and describe our experience conducting overviews, and to provide guidance on the steps involved.
Methods: Descriptive summary of our experience conducting over 30 overviews, including recommendations and practical considerations for issues commonly encountered.
Results: Overviews are broader in scope than any individual SR, but use methods similar to SRs. Searching, screening, and inclusion are typically more straightforward at the overview level, but procedures differ based on whether non-Cochrane SRs are included alongside Cochrane SRs. There are often a number of relevant non-Cochrane SRs that may overlap in content with relevant Cochrane SRs. In these cases, extracting information from each SR about the scope (population, intervention, comparison, outcomes, study designs, setting), quality (using AMSTAR), year of publication, and included studies can make it easier to determine which SRs would be most appropriate for inclusion in the overview. Steps must be taken to describe the characteristics and methodological quality of the included SRs, as well as the studies within those SRs. Extraction and re-analysis of study data from SRs should be driven by a well-defined clinical question, and not by the individual SR data. We encountered challenges when including non-Cochrane SR in overviews and when grading the quality of evidence.
Conclusions: Overviews bring together the highest quality evidence into a "friendly front end" for decision-makers. However, including non-Cochrane SRs in overviews is often challenging, and many issues stem from reliance on methods and decisions made by authors at the SR level. We are currently conducting research on overview methodology and will use this research to develop evidence-based guidance for the conduct and reporting of overviews.
Objectives: To summarize and describe our experience conducting overviews, and to provide guidance on the steps involved.
Methods: Descriptive summary of our experience conducting over 30 overviews, including recommendations and practical considerations for issues commonly encountered.
Results: Overviews are broader in scope than any individual SR, but use methods similar to SRs. Searching, screening, and inclusion are typically more straightforward at the overview level, but procedures differ based on whether non-Cochrane SRs are included alongside Cochrane SRs. There are often a number of relevant non-Cochrane SRs that may overlap in content with relevant Cochrane SRs. In these cases, extracting information from each SR about the scope (population, intervention, comparison, outcomes, study designs, setting), quality (using AMSTAR), year of publication, and included studies can make it easier to determine which SRs would be most appropriate for inclusion in the overview. Steps must be taken to describe the characteristics and methodological quality of the included SRs, as well as the studies within those SRs. Extraction and re-analysis of study data from SRs should be driven by a well-defined clinical question, and not by the individual SR data. We encountered challenges when including non-Cochrane SR in overviews and when grading the quality of evidence.
Conclusions: Overviews bring together the highest quality evidence into a "friendly front end" for decision-makers. However, including non-Cochrane SRs in overviews is often challenging, and many issues stem from reliance on methods and decisions made by authors at the SR level. We are currently conducting research on overview methodology and will use this research to develop evidence-based guidance for the conduct and reporting of overviews.