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26. Jahrestagung des Netzwerks Evidenzbasierte Medizin e. V.

Netzwerk Evidenzbasierte Medizin e. V. (EbM-Netzwerk)

26. - 28.03.2025, Freiburg

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Availability of randomized trial protocols and the timing of their accessibility: a repeated meta-research study

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  • author Christof Manuel Schönenberger - University Hospital Basel, Division of Clinical Epidemiology, Basel, Schweiz
  • author Malena Chiaborelli - University Hospital Basel, Division of Clinical Epidemiology, Basel, Schweiz
  • author Ala Taji Heravi - University Hospital Basel, Division of Clinical Epidemiology, Basel, Schweiz
  • author Lukas Kübler - University of Basel, Department of Biomedicine, Basel, Schweiz
  • author Pooja Gandhi - University of Toronto, University Health Network, Kanada
  • author Zsuzsanna Kontar - University of Pécs, MTA-PTE Lendület, Pécs, Ungarn
  • author Julia Hüllstrung - University Hospital Basel, Division of Clinical Epidemiology, Basel, Schweiz
  • author Mona Elalfy - University Hospital Basel, Division of Clinical Epidemiology, Basel, Schweiz
  • author Dmitry Gryaznov - University Hospital Basel, Division of Clinical Epidemiology, Basel, Schweiz
  • author Belinda von Niederhäusern - Roche Pharma AG, Schweiz
  • author Anette Blümle - University of Freiburg, Clinical Trials Unit, Freiburg, Deutschland
  • author Jason Busse - McMaster University, Department of Anesthesia, Kanada
  • author Szimonetta Lohner - University of Pécs, MTA-PTE Lendület, Pécs, Ungarn
  • author Sally Hopewell - University of Oxford, Centre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Oxford, Großbritannien
  • author Alexandra Griessbach - University Hospital Basel, Division of Clinical Epidemiology, Basel, Schweiz
  • Matthias Briel - University Hospital Basel, Division of Clinical Epidemiology, Basel, Schweiz; McMaster University, Department of Health Research Methods, Evidence, and Impact, Kanada
  • Benjamin Speich - University Hospital Basel, Division of Clinical Epidemiology, Basel, Schweiz

Die EbM der Zukunft – packen wir’s an!. 26. Jahrestagung des Netzwerks Evidenzbasierte Medizin. Freiburg, 26.-28.03.2025. Düsseldorf: German Medical Science GMS Publishing House; 2025. Doc25ebmV-08-05

doi: 10.3205/25ebm044, urn:nbn:de:0183-25ebm0447

Published: March 27, 2025

© 2025 Schönenberger et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.

Outline

Text

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.

Outline

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 External link