Background: Intervention effects can be presented alternatively in relative (such as relative risk) or absolute terms (such as risk difference). To avoid misleading users systematic reviews (SRs) authors should include both absolute and relative estimates. There is limited information about this topic and there are important potential implications for decision-making in healthcare. We therefore believe it is important to explore how this issue is managed in published systematic reviews.

Objectives: To determine the proportion of SRs reporting absolute effects (AE) and to evaluate how these are derived and interpreted. Additionally, we will explore the association of pre-specified study characteristics with the report of AE.

Methods: We searched the Medline and the Cochrane Database of Systematic Reviews for systematic reviews of randomized controlled trials published in 2010 and reporting a meta-analysis of dichotomous outcome(s). After teams of two reviewers screened studies for eligibility, we randomly selected 75 Cochrane and 75 non-Cochrane reviews. Teams of two reviewers are currently abstracting data using standardized, piloted forms and written instructions.

Results: Data abstraction is ongoing. The results of analyses will be available for presentation at the colloquium.

Conclusions: Our results will inform the extent of limitations of determining and reporting AE in SRs and lay the foundation for further studies about the potential implications for decision-making.