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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/19144

Title: Publication bias in meta-analyses from the Cochrane Database of Systematic Reviews
Authors: Kicinski, Michal
Springate, David A.
Kontopantelis, Evangelos
Issue Date: 2015
Publisher: WILEY-BLACKWELL
Citation: STATISTICS IN MEDICINE, 34 (20), p. 2781-2793
Abstract: We used a Bayesian hierarchical selection model to study publication bias in 1106 meta-analyses from the Cochrane Database of Systematic Reviews comparing treatment with either placebo or no treatment. For meta-analyses of efficacy, we estimated the ratio of the probability of including statistically significant outcomes favoring treatment to the probability of including other outcomes. For meta-analyses of safety, we estimated the ratio of the probability of including results showing no evidence of adverse effects to the probability of including results demonstrating the presence of adverse effects. Results: In the meta-analyses of efficacy, outcomes favoring 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 favorable to treatment was larger in meta-analyses including older studies. Conclusions: In the largest study on publication bias in meta-analyses to date, we found evidence of publication bias in Cochrane systematic reviews. In general, publication bias is smaller in meta-analyses of more recent studies, indicating their better reliability and supporting the effectiveness of the measures used to reduce publication bias in clinical trials. Our results indicate the need to apply currently underutilized meta-analysis tools handling publication bias based on the statistical significance, especially when studies included in a meta-analysis are not recent. Copyright (c) 2015 John Wiley & Sons, Ltd.
Notes: [Kicinski, Michal] Hasselt Univ, Fac Sci, Diepenbeek, Belgium. [Springate, David A.; Kontopantelis, Evangelos] Univ Manchester, Inst Populat Hlth, Sch Primary Care Res, Ctr Primary Care,Natl Inst Hlth Res, Manchester, Lancs, England. [Springate, David A.] Univ Manchester, Inst Populat Hlth, Ctr Biostat, Manchester, Lancs, England. [Kontopantelis, Evangelos] Univ Manchester, Inst Populat Hlth, Ctr Hlth Informat, Manchester, Lancs, England.
URI: http://hdl.handle.net/1942/19144
DOI: 10.1002/sim.6525
ISI #: 000358421500001
ISSN: 0277-6715
Category: A1
Type: Journal Contribution
Validation: ecoom, 2016
Appears in Collections: Research publications

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