Impact of inclusion of industry trial results registries as an information source for systematic reviews

Ref ID 551
First Author R. Potthast
Journal PLOS ONE
Year Of Publishing 2014
Keywords Harms
Grey literature
Publication bias
Problem(s) Lack of supplementary searches beyond databases
Grey literature excluded
Number of systematic reviews included 150
Summary of Findings In 23/150 reviews, relevant trials were missed from registries. In 6/23 reviews, inclusion of these omitted trials changed the treatment effect. In 17/23 reviews, the treatment effect was unchanged. Less than half of all the systematic reviews considered as an information source.
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