Article type
Year
Abstract
Background: Trial registration is known to improve research transparency and will ultimately strengthen the validity and value of the scientific evidence base. In September 2004, the International Committee of Medical Journal Editors (ICMJE) announced they would no longer publish trials that were not registered at inception. If this initiative is successful, it has the potential to substantially reduce the effects of publication and selective reporting biases. However, the extent to which trial registration will facilitate the work of Cochrane review authors is still unclear at present.
Objectives: The study is aimed to evaluate the impact of trial registration on assessing selective reporting bias in Cochrane reviews.
Methods: We identified all included trials published in Cochrane Database of Systematic Reviews 2012, Issue 3. We evaluated the impact of trial registration in facilitating the work of Cochrane review authors to assess the selective reporting bias of each trial.
Results: Of 32 published Cochrane reviews examined, 399 included trials were evaluated. 29.8% (119/399) of the included trials were assessed as low risk of selective reporting bias, 19.8% (79/399) as high risk, and 33.1% (132/399) as unclear risk. In these 330 included trials, only 11 trials were assessed with the help of trial registration. Reviewers did not assess selective reporting bias in 17.3% (69/399) of studies because there is no protocol available and no enough information to make judgments.
Conclusions: The findings reveal the complexity and impracticality in assessing selective reporting bias with no protocol available. Our results disclose that trial registration has not yet become part of the current research paradigm internationally, researchers should pay more attention in registering their studies in a public trials registry at or before the onset of enrolment.
Objectives: The study is aimed to evaluate the impact of trial registration on assessing selective reporting bias in Cochrane reviews.
Methods: We identified all included trials published in Cochrane Database of Systematic Reviews 2012, Issue 3. We evaluated the impact of trial registration in facilitating the work of Cochrane review authors to assess the selective reporting bias of each trial.
Results: Of 32 published Cochrane reviews examined, 399 included trials were evaluated. 29.8% (119/399) of the included trials were assessed as low risk of selective reporting bias, 19.8% (79/399) as high risk, and 33.1% (132/399) as unclear risk. In these 330 included trials, only 11 trials were assessed with the help of trial registration. Reviewers did not assess selective reporting bias in 17.3% (69/399) of studies because there is no protocol available and no enough information to make judgments.
Conclusions: The findings reveal the complexity and impracticality in assessing selective reporting bias with no protocol available. Our results disclose that trial registration has not yet become part of the current research paradigm internationally, researchers should pay more attention in registering their studies in a public trials registry at or before the onset of enrolment.