Improving the reporting and use of trial results in clinical trials registries: global practices, barriers, and recommendations

Abstract

Background and Objectives

Recent initiatives promoted results reporting on clinical trials registries to improve transparency and reduce publication bias. However, local reports suggest that results reporting on registries is often inadequate, limiting their usefulness for evidence synthesis. We aimed to 1) provide an overview of results reporting practices across clinical trials registries globally, 2) identify barriers and facilitators to reporting and using results from trials registries, and 3) develop recommendations to improve reporting and usability of results in trials registries.

Study Design and Setting

Three-part mixed methods study. Part 1: Descriptive analysis of results reporting practices for randomized controlled trials (RCTs) starting between 2010 and 2022 across six trials registries (one from each World Health Organization region), with an in-depth analysis focusing on reporting formats and accessibility. Part 2: Two separate online surveys targeting trial registrants and evidence users. Part 3: Discussion among author group to generate recommendations.

Results

Part 1: Our sample included 201,265 RCTs, with 17% (33,163 trials) reporting some form of results on a registry. A subset showed 63% of posted results accessible in the registry record, with 64% to 98% of results data available in a reusable format. Part 2: 86% (194/225) of registrants were aware of registry results reporting possibilities, but time, effort, and fear of publishing interference were barriers. For evidence users, 51% (36/70) had used registry results, with barriers including mistrust of non–peer-reviewed data and difficulty locating results. Part 3: Recommendations include standardizing registry interfaces, addressing misconceptions, and fostering trust in registry-reported results.

Conclusion

Results reporting practices on registries are increasing. Improving these requires better infrastructure, policies, training, and funding. With adequate support, registries can become essential for transparent and efficient evidence dissemination, enhancing research quality, and reducing duplication.

Plain Language Summary

Clinical trials registries are online databases where researchers register medical studies and share their status, details, and results. These registries exist globally and allow researchers to track ongoing studies and emerging evidence on a topic. They also enable the public to identify trials they may be interested to participate in. Although regulations require researchers to share study results on registries within a year of study completion, only a fraction of results are currently available. Our project 1) evaluated the reporting of study results across different trials registries, 2) surveyed individuals involved in reporting and using study findings from registries, and 3) developed recommendations to improve availability and usefulness of these results. We found that increasing trust in registry-reported results, improving registry systems (ie, interfaces, processes), and providing better guidance are necessary steps to enhance reporting and use of registry results. Implementing these changes will make it easier to verify study findings, provide accurate guidelines to physicians, and improve patient care.