Publication bias in meta-analyses from the Cochrane Database of Systematic Reviews

Ref ID 89
First Author M. Kicinski
Journal STATISTICS IN MEDICINE
Year Of Publishing 2015
URL https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/sim.6525?download=true
Keywords Cochrane
Publication bias
General medical
Problem(s) Poor consideration of publication bias
Perpetuates citation of poor quality primary study data
Weaknesses identified in some Cochrane reviews
Number of systematic reviews included 329
Summary of Findings Data from 1106 meta-analyses from 329 Cochrane reviews comparing treatment with placebo or no treatment were included. In the meta-analyses of efficacy, outcomes favouring treatment had on average a 27% (95% Credible Interval (CI): 18% to 36%) higher probability to be included than other outcomes. In the meta-analyses of safety, results showing no evidence of adverse effects were on average 78% (95% CI: 51% to 113%) more likely to be included than results demonstrating that adverse effects existed. In general, the amount of over-representation of findings favourable to treatment was larger in meta-analyses including older studies. The number of statistically significant findings in meta-analyses was larger than expected from the power of the individual studies.
Did the article find that the problem(s) led to qualitative changes in interpretation of the results? Not Applicable
Are the methods of the article described in enough detail to replicate the study? No