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 • General medical
• Publication bias
• Cochrane
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? N/A
Are the methods of the article described in enough detail to replicate the study? No