A meta-research study of randomized controlled trials found infrequent and delayed availability of protocols
Open accessAbstract
OBJECTIVES: Availability of randomized controlled trial (RCT) protocols is essential for the interpretation of trial results and research transparency. STUDY DESIGN AND SETTING: In this study, we determined the availability of RCT protocols approved in Switzerland, Canada, Germany, and the United Kingdom in 2012. For these RCTs, we searched PubMed, Google Scholar, Scopus, and trial registries for publicly available protocols and corresponding full-text publications of results. We determined the proportion of RCTs with (1) publicly available protocols, (2) publications citing the protocol, and (3) registries providing a link to the protocol. A multivariable logistic regression model explored factors associated with protocol availability. RESULTS: Three hundred twenty-six RCTs were included, of which 118 (36.2%) made their protocol publicly available; 56 (47.6% 56 of 118) provided as a peer-reviewed publication and 48 (40.7%, 48 of 118) provided as supplementary material. A total of 90.9% (100 of 110) of the protocols were cited in the main publication, and 55.9% (66 of 118) were linked in the clinical trial registry. Larger sample size (>500; odds ratio [OR] = 5.90, 95% confidence interval [CI], 2.75-13.31) and investigator sponsorship (OR = 1.99, 95% CI, 1.11-3.59) were associated with increased protocol availability. Most protocols were made available shortly before the publication of the main results. CONCLUSION: RCT protocols should be made available at an early stage of the trial.
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Protocols and statistical analysis plans play a central role in enhancing the transparency, reproducibility, and interpretation of trial results.
“Given the central role of protocols and statistical analysis plans in enhancing the transparency, reproducibility, and interpretation of trial results, there is a strong ethical and scientific rationale for these key documents to be publicly available.74 75 76 77 78”
From SPIRIT 2025 explanation and elaboration: updated guideline for protocols of randomised trials (2025) · cites this paper as [75]
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References 32 · Cited by 17
Research works printed but not linked: 2
- Nosek BA, Ebersole CR, DeHaven AC, Mellor DT. The preregistra- tion revolution. Proc Natl Acad Sci 2018;115(11):2600e6.
- Resources for authors the BMJ. Available at http://web.archive.org/ web/20160527210426/http://www.bmj.com/about-bmj/resources- authors. Accessed February 3, 2022.
- Authors
- Schönenberger, C. M., Griessbach, A., Taji Heravi, A., Gryaznov, D., Gloy, V. L., Lohner, S., Klatte, K., Ghosh, N., Lee, H., Mansouri, A., Marian, I. R., Saccilotto, R., Nury, E., Busse, J. W., von Niederhäusern, B., Mertz, D., Blümle, A., Odutayo, A., Hopewell, S., Speich, B., & Briel, M.
- Affiliations
- University of Basel (CH)
- University of Pecs (HU)
- University of Oxford (GB)
- University of Freiburg (DE)
- McMaster University (CA)
- Corresponding author
- Schönenberger, Christof Manuel
- ORCID
- Venue
- Journal of Clinical Epidemiology
- Publisher
- Elsevier BV
- Published
- 2022-09
- Volume
- 149
- Pages
- 45-52
- ISSN
- 0895-4356 (ISSN-L)
- OpenAlex
- W4281713379
- Cited by
- 17
- References
- 32
- Citations by year
- 2026: 2 · 2025: 11 · 2024: 3 · 2023: 1
- FWCI
- 2.26
- Type
- journal article
- Language
- en
- Open access
- hybrid
- doi.org
- Licence
- Locations
- Journal of Clinical Epidemiology (publishedVersion, cc-by-nc-nd)
- PubMed (publishedVersion)
- Repository of the Academy's Library (Library of the Hungarian Academy of Sciences) (acceptedVersion)
- Funders
- Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (P4P4PM_194496)
- Hungarian Scientific Research Fund
- Magyar Tudományos Akadémia (BO/00498/17/5)
- Topics
- Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
- Social Sciences › Decision Sciences › Information Systems and Management › Academic Publishing and Open Access
- Life Sciences › Pharmacology, Toxicology and Pharmaceutics › Pharmacology › Pharmaceutical industry and healthcare
- Keywords
- randomized controlled trials, research transparency, clinical trial registries, publication of trial results, sample size, meta-research
- MeSH terms
- Germany, Humans, Registries, Research Personnel, Odds Ratio, Randomized Controlled Trials as Topic, Sample Size
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