Article type
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Abstract
Background: Studies included in a meta-analysis often differ in methodological, patient, and intervention characteristics, and outcome measures, differences that may result in heterogeneity of treatment effects. Subgroup analyses may explain such heterogeneity. However, both inappropriate conduct and reporting of subgroup analyses may lead to misguided clinical and policy decisions, and the extent to which systematic review authors undertake subgroup analyses and the quality of their conduct and reporting remain uncertain.
Objective: To examine the extent to which subgroup analyses are conducted, and to compare the quality of conduct and reporting of subgroup analyses between Cochrane versus non-Cochrane reviews.
Methods: We searched the Cochrane Database of Systematic Reviews and the Medline for systematic reviews published in 2010 that included a meta-analysis of dichotomous outcome reported in randomized controlled trials. Teams of two reviewers screened studies for eligibility. We randomly selected 75 Cochrane and 75 non-Cochrane reviews from eligible studies. Teams of two reviewers are currently abstracting data using standardized, piloted forms guided with written instructions We will focus on subgroup analyses of aggregate data meta-analyses, and the unit of analysis is an individual systematic review. Our analysis will examine whether authors planned to explore heterogeneity, whether they were able to explore heterogeneity, reasons for the failure of exploring heterogeneity, and approaches to exploring heterogeneity. We will examine whether a subgroup hypothesis was pre-specified, the number of subgroup hypotheses tested, the number of outcomes and corresponding effect measures used for subgroup analyses, and whether a test of interaction was used. For each major issue, we will compare practice in Cochrane versus non-Cochrane reviews.
Results: The results of analyses will be available for presentation at the colloquium.
Discussion: The results of this study will provide an important insight about the quality of conduct and reporting of subgroup analyses in systematic reviews.
Objective: To examine the extent to which subgroup analyses are conducted, and to compare the quality of conduct and reporting of subgroup analyses between Cochrane versus non-Cochrane reviews.
Methods: We searched the Cochrane Database of Systematic Reviews and the Medline for systematic reviews published in 2010 that included a meta-analysis of dichotomous outcome reported in randomized controlled trials. Teams of two reviewers screened studies for eligibility. We randomly selected 75 Cochrane and 75 non-Cochrane reviews from eligible studies. Teams of two reviewers are currently abstracting data using standardized, piloted forms guided with written instructions We will focus on subgroup analyses of aggregate data meta-analyses, and the unit of analysis is an individual systematic review. Our analysis will examine whether authors planned to explore heterogeneity, whether they were able to explore heterogeneity, reasons for the failure of exploring heterogeneity, and approaches to exploring heterogeneity. We will examine whether a subgroup hypothesis was pre-specified, the number of subgroup hypotheses tested, the number of outcomes and corresponding effect measures used for subgroup analyses, and whether a test of interaction was used. For each major issue, we will compare practice in Cochrane versus non-Cochrane reviews.
Results: The results of analyses will be available for presentation at the colloquium.
Discussion: The results of this study will provide an important insight about the quality of conduct and reporting of subgroup analyses in systematic reviews.