Authors seldom report the most patient-important outcomes and absolute effect measures in systematic review abstracts.

OBJECTIVES: Explicit reporting of absolute measures is important to ensure treatment effects are correctly interpreted. We examined the extent to which authors report absolute effects for patient-important outcomes in abstracts of systematic review (SR). STUDY DESIGN AND SETTING: We searched OVID MEDLINE and Cochrane Database of Systematic Reviews to identify eligible SRs published in the year 2010. Citations were stratified into Cochrane and non-Cochrane reviews, with repeated random sampling in a 1:1 ratio. Paired reviewers screened articles and recorded abstract characteristics, including reporting of effect measures for the most patient-important outcomes of benefit and harm. RESULTS: We included 96 Cochrane and 94 non-Cochrane reviews. About 117 (77.5%) relative measures were reported in abstracts for outcomes of benefit, whereas only 34 (22.5%) absolute measures were reported. Similarly, for outcomes of harm, 41 (87.2%) relative measures were provided in abstracts, compared with only 6 (12.8%) absolute measures. Eighteen (9.5%) abstracts reported both absolute and relative measures for outcomes of benefit, whereas only two (1.1%) abstracts reported both measures for outcomes of harm. Results were similar between Cochrane and non-Cochrane reviews. CONCLUSION: SR abstracts seldom report measures of absolute effect. Journal editors should insist that authors report both relative and absolute effects for patient-important outcomes.