Abstract
Factors Associated With Improper Clinical Trial Registration, Registration Deficiencies, and Publication Status of Submissions to The BMJ
David Blanco,1 Elizabeth Loder,2,3 Sophie Cook,3 Martí Casals,4,5 Jordi Cortés,6 Aïda Cadellans-Arroniz,1 Victor Zárate,1 Ella Hubbard,3 Sara Schroter3,7
Objective
In 2005, the International Committee of Medical Journal Editors (ICMJE) mandated that all clinical trials be properly registered—that is, registered in an approved registry at or before the enrollment of the first participant.1 Despite improved registration rates, many trials published in journals claiming adherence to ICMJE registration policy remain improperly registered.2 This study aimed to (1) identify variables associated with improper registration; (2) examine types of registration deficiencies, publication status, and disclosure of registration issues in improperly registered trials; and (3) assess authors’ claims of proper registration.
Design
This observational study analyzed 239 improperly and 239 properly registered trials submitted to The BMJ (2019-2023). For objective 1, we collected data on trial design, setting, sample size, intervention type, number of authors, corresponding author region, mention of Consolidated Standards of Reporting Trials (CONSORT) guidelines, submission year, and funding source. For objective 2, we examined improperly registered trials submitted between 2019 and 2021, focusing on registration deficiency type (retrospective registration in approved registry, registration in unapproved registry, or no registration), registration delay (for retrospectively registered trials), and publication status. For published trials, we recorded Journal Impact Factor, ICMJE affiliation, time to publication, and disclosure of registration issues. For objective 3, we assessed authors’ claims of prospective registration for improperly registered trials. Analyses included multivariable logistic regression and descriptive statistics.
Results
Several variables were associated with reduced odds of improper registration: larger sample size (101-500 vs 1-100; odds ratio [OR], 0.43 [95% CI, 0.22-0.84]), corresponding authors from Oceania (reference: Europe; OR, 0.35 [95% CI, 0.14-0.82]), more authors (10 vs 1; OR, 0.53 [95% CI, 0.32-0.87]), CONSORT mention (OR, 0.22 [95% CI, 0.06-0.67]), recent submissions (2021-2023 vs 2019-2020; OR, 0.63 [95% CI, 0.42-0.96]), and funding (eg, nonprofit vs no funding; OR, 0.20 [95% CI, 0.09-0.41]). Trials with authors from Asia (OR, 1.75 [95% CI, 1.07-2.89]) had higher odds of improper registration. Of 176 improperly registered trials, 82.4% (n = 145) were retrospectively registered in approved registries (median delay, 6.54 months; Q1, 2.50 months; Q3, 18.67 months), 13.1% (n = 23) were unregistered, and 4.5% (n = 8) used unapproved registries. Most (88.1% [n = 155 trials]) were later published, including 1 in The BMJ. Among these, 89.0% (n = 138) appeared in journals with an Impact Factor (median, 5.39; Q1, 3.98; Q3, 10.40) and 62.0% (n = 96) in journals claiming adherence with ICMJE registration policy. Median time to publication was 12 months (Q1, 8 months; Q3, 19 months). Only about one-sixth explicitly acknowledged the registration issue at the time of publication. Of 72 responses to The BMJ’s submission question on prospective registration (2021-2023), 83.3% (n = 60) incorrectly claimed compliance.
Conclusions
We identified variables associated with improper trial registration. Retrospective registration was common, and most improperly registered trials rejected by The BMJ were later published in other ICMJE-affiliated journals. ICMJE journals should strengthen processes to better identify and reject improperly registered trials.
References
1. International Committee of Medical Journal Editors. Clinical trials. Accessed January 23, 2025. https://www.icmje.org/recommendations/browse/publishing-and-editorial-issues/clinical-trial-registration.html
2. Trinquart L, Dunn AG, Bourgeois FT. Registration of published randomized trials: a systematic review and meta-analysis. BMC Med. 2018;16(1):173. doi:10.1186/s12916-018-1168-6
1Department of Physiotherapy, Universitat Internacional de Catalunya, Barcelona, Spain, dblanco@uic.es; 2Department of Neurology, Brigham and Women’s Hospital, Boston, MA, US; 3The BMJ, London, UK; 4National Institute of Physical Education of Catalonia, University of Barcelona, Barcelona, Spain; 5Sport and Physical Activity Studies Centre, Faculty of Medicine, University of Vic – Central University of Catalonia, Barcelona, Spain; 6Biostatistics and Bioinformatics Research Group, Department of Statistics and Operations Research and Institute for Research and Innovation in Health, Universitat Politècnica de Catalunya, Barcelona, Spain; 7Faculty of Public Health and Policy, London School of Hygiene & Tropical Medicine, London, UK.
Conflict of Interest Disclosures
Sophie Cook and Sara Schroter are full-time employees of the BMJ Group and Elizabeth Loder is a part-time employee.