The impact of outcome reporting bias in randomised controlled trials on a cohort of systematic reviews

Ref ID 471
First Author J. J. Kirkham
Journal BMJ
Year Of Publishing 2010
URL https://www.bmj.com/content/bmj/340/bmj.c365.full.pdf
Keywords Cochrane
Multiplicity
Missing data
General medical
Problem(s) Multiplicity of outcomes and lack of pre-specification for outcome reporting
Failure to address missing outcome data in analyses
Weaknesses identified in some Cochrane reviews
Number of systematic reviews included 283
Summary of Findings 55% of the included reviews did not include full data for the review primary outcome of interest from all eligible trials. 34% of included reviews contained at least one trial with high suspicion of outcome reporting bias for the review primary outcome. In a sensitivity analysis of the primary outcome of interest, the treatment effect estimate was reduced by 20% or more in 23% of reviews. Of the meta-analyses with a statistically significant result 19% became non-significant after adjustment for outcome reporting bias and 26% would have overestimated the treatment effect by 20% or more.
Did the article find that the problem(s) led to qualitative changes in interpretation of the results? Yes
Are the methods of the article described in enough detail to replicate the study? Yes