We evaluated what guidance exists in the literature to improve the transparency of studies that make secondary use of health data. To find relevant literature, we searched PubMed and Google Scholar and drafted a list of health organizations based on our personal expertise. We quantitatively and qualitatively coded different types of research transparency: registration, methods reporting, results reporting, data sharing, and code sharing. We found 54 documents that provide recommendations to improve the transparency of studies making secondary use of health data, mainly in relation to study registration (n = 27) and methods reporting (n = 39). Only three documents made recommendations on data sharing or code sharing. Recommendations for study registration and methods reporting mainly came in the form of structured documents like registration templates and reporting guidelines. Aside from the recommendations aimed directly at researchers, we found 31 recommendations aimed at the wider research community, typically on how to improve research infrastructure. Limitations or challenges of improving transparency were rarely mentioned, highlighting the need for more nuance in providing transparency guidance for studies that make secondary use of health data.

The authors have declared no competing interest.

This study is part of the project HiGHmed, which is funded by the Medical Informatics Initiative of the German Federal Ministry of Education and Research.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

All our data is available on the OSF repository of our project at https://osf.io/2nup4. The preregistration is available at https://osf.io/7864h. A document with deviations from our preregistration is available at https://osf.io/m4ehx.

https://osf.io/2nup4