| Description: |
Objectives To identify variables associated with non-prospective registration of clinical trials submitted to The BMJ ; examine deficiencies in registration, disclosure of deficiencies, and subsequent publication status of such trials; and assess the authors’ claims of prospective registration. Design Observational study. Setting The BMJ, London. Population 239 of 287 submissions to The BMJ (2019-23) reporting clinical trial results as defined by the International Committee of Medical Journal Editors (ICMJE) and flagged by editors as potentially not prospectively registered, and 239 trials prospectively registered in an ICJME accepted registry from a randomised list of all clinical trial submissions in the same period. Main outcome measures Study outcomes included non-prospective registration in an ICJME accepted registry and, for non-prospectively registered trials, deficiencies in registration deficiencies in registration (retrospective in an ICJME accepted registry, registration in a non-ICJME accepted registry, or no registration), delay in registration of retrospectively registered trials, and subsequent publication status. Time to publication and disclosure of registration deficiencies on publication were also assessed, along with the journal’s impact factor and whether the journal claimed adherence to the ICMJE registration recommendations. Results Reduced odds of non-prospective registration in an ICMJE accepted registry were associated with larger sample sizes (101-500 v 1-100; odds ratio 0.43, 95% confidence interval 0.22 to 0.84), corresponding authors from Oceania (reference: Europe; 0.35, 0.14 to 0.82), a greater number of authors (10 v 5; 0.71, 0.59 to 0.87), mention of Consolidated Standards Of Reporting Trials (0.22, 0.06 to 0.67), more recent submissions (2021-23 v 2019-20; 0.63, 0.42 to 0.95), and presence of funding (eg, non-profit v no funding or no information; 0.20, 0.09 to 0.41). Higher odds were observed for corresponding authors based in Asia (reference: Europe; 1.75, 1.07 to ... |