This study describes access to individual patient-level data from randomized clinical trials during the COVID-19 pandemic to determine whether the intent to share what was reported in the registry, publication, or preprint was consistent with actual data access.

Randomized controlled trials (RCTs) are essential to support clinical decision making. We assessed the transparency, completeness and consistency of reporting of 244 reports (120 peer-reviewed journal publications; 124 preprints) of RCTs assessing pharmacological interventions for the treatment of COVID-19 published the first 17 months of the pandemic (up to May 31, 2021). Transparency was poor. Only 55% of trials were prospectively registered; 39% made their full protocols available and 29% provided access to their statistical analysis plan. Only 6% completely reported the most important information. Primary outcome(s) reported in trial registries and published reports were inconsistent in 47% of trials. Of the 124 RCTs published as preprint, 76 were secondarily published in a peer-reviewed journal. There was no major improvement after the peer-review process. Lack of transparency, completeness and consistency of reporting is an important barrier to trust, interpretation and synthesis in COVID-19 clinical trials.

Background In the context of the COVID-19 pandemic, randomized controlled trials (RCTs) are essential to support clinical decision-making. We aimed (1) to assess and compare the reporting characteristics of RCTs between preprints and peer-reviewed publications and (2) to assess whether reporting improves after the peer review process for all preprints subsequently published in peer-reviewed journals. Methods We searched the Cochrane COVID-19 Study Register and L·OVE COVID-19 platform to identify all reports of RCTs assessing pharmacological treatments of COVID-19, up to May 2021. We extracted indicators of transparency (e.g., trial registration, data sharing intentions) and assessed the completeness of reporting (i.e., some important CONSORT items, conflict of interest, ethical approval) using a standardized data extraction form. We also identified paired reports published in preprint and peer-reviewed publications. Results We identified 251 trial reports: 121 (48%) were first published in peer-reviewed journals, and 130 (52%) were first published as preprints. Transparency was poor. About half of trials were prospectively registered (n = 140, 56%); 38% (n = 95) made their full protocols available, and 29% (n = 72) provided access to their statistical analysis plan report. A data sharing statement was reported in 68% (n = 170) of the reports of which 91% stated their willingness to share. Completeness of reporting was low: only 32% (n = 81) of trials completely defined the pre-specified primary outcome measures; 57% (n = 143) reported the process of allocation concealment. Overall, 51% (n = 127) adequately reported the results for the primary outcomes while only 14% (n = 36) of trials adequately described harms. Primary outcome(s) reported in trial registries and published reports were inconsistent in 49% (n = 104) of trials; of them, only 15% (n = 16) disclosed outcome switching in the report. There were no major differences between preprints and peer-reviewed publications. Of the 130 RCTs published as preprints, 78 were subsequently published in a peer-reviewed journal. There was no major improvement after the journal peer review process for most items. Conclusions Transparency, completeness, and consistency of reporting of COVID-19 clinical trials were insufficient both in preprints and peer-reviewed publications. A comparison of paired reports published in preprint and peer-reviewed publication did not indicate major improvement.