Artikel
Availability of randomized trial protocols and the timing of their accessibility: a repeated meta-research study
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Veröffentlicht: | 27. März 2025 |
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Background/research question: Making protocols of randomized clinical trials (RCT) publicly available is important to improve transparency and quality of medical research. In a previous study [1], we found that amongst RCTs receiving ethical approval in 2012, only 36% made their protocol publicly available. Within this repeated meta-research study, we aimed to assess if publicly sharing RCT protocols has become more common for RCTs approved in 2016.
Methods: Using a representative sample of RCTs, receiving ethical approval in 2016 in the UK, Switzerland, Canada, or Germany, we investigated the number of available protocols by searching PubMed, Google Scholar, and trial registries and Google. Up to January 2024 (final update planned in June 2024), we systematically searched in duplicate for (i) protocols available as peer-reviewed publications, (ii) protocols attached to trial registries and (iii) protocols shared with results publications of RCTs. We used multivariable logistic regression to examine the association of protocol availability with trial characteristics such as type of sponsor, sample size, drug vs. non-drug interventions, and multi-center vs. single-center status. We compared all results with a previous study examining protocol availability in RCTs approved in 2012.
Results: We included 346 RCTs approved in 2016, of which 222 (64%) had an available protocol. Seventy-four protocols were available as peer-reviewed publication, 144 as uploaded file on a trial registry, and 86 as supplementary material to a results publication. Larger sample size (>500; adjusted odds ratio [aOR] 5.2, 95% confidence interval [CI], 2.1–12.8), multi-center status (vs. single-center status; aOR 3.7, 95% CI, 1.9–7.4) and industry sponsorship (vs. non-industry sponsorship; aOR 2.5, 95% CI, 1.4–4.7) were associated with increased protocol availability. Compared to RCTs approved in 2012, protocol availability improved substantially for industry sponsored trials (82% 2016 vs. 35% 2012), drug trials (76% vs. 37%) and multi-center trials (77% vs. 40%).
Conclusion: The availability of RCT protocols has improved significantly for RCTs approved in 2016 compared with 2012. This is mainly driven by increased availability of industry protocols. Efforts to improve protocol availability should be continued, especially for non-industry sponsored RCTs.
Competing interests: No conflict of interest.
References
- 1.
- Schönenberger CM, Griessbach A, Taji Heravi A, et al. A meta-research study of randomized controlled trials found infrequent and delayed availability of protocols. J Clin Epidemiol. 2022;149:45-52. DOI: 10.1016/j.jclinepi.2022.05.014