Prevalence of clinical trial status discrepancies: A cross-sectional study of 10,492 trials registered on both ClinicalTrials.gov and the European Union Clinical Trials Register

Abstract

ObjectiveTrial registries are a key source of information for clinicians and researchers. While building OpenTrials, an open database of public trial information, we identified errors and omissions in registries, including discrepancies between descriptions of the same trial in different registries. We set out to ascertain the prevalence of discrepancies in trial completion status using a cohort of trials registered on both the European Union Clinical Trials Register (EUCTR) and ClinicalTrials.gov.Study design and settingWe used matching titles and registry IDs provided by both registries to build a cohort of dual-registered trials. Completion statuses were compared; we calculated descriptive statistics on the prevalence of discrepancies.Results11,988 dual-registered trials were identified. 1,496 did not provide a comparable completion status, leaving 10,492 trials. 16.2% were discrepant on completion status. The majority of discrepancies (90.5%) were a ‘completed’ trial on ClinicalTrials.gov inaccurately marked as ‘ongoing’ on EUCTR. Overall, 33.9% of dual-registered trials described as 'ongoing' on EUCTR were listed as 'completed' on ClinicalTrials.gov.ConclusionCompletion status on registries is commonly inaccurate. Previous work on publication bias may underestimate non-reporting. We describe simple steps registry owners and trialists could take to improve accuracy.

Twenty‐two years’ experience registering trials in a low‐middle income country: The Peruvian Clinical Trial Registry

“…At the same time, Reveiz et al reported lack of methodological information in RCTs of seven international registries, and Kosa et al reported the disagreement in methodological information between publication and registry . Also, Fleminger et al describe the inaccuracy on completion status between Clinicaltrials.gov and the European registry . REPEC's registries do not report methodological and intervention characteristics before 2011.…”

A Decade in Review: A Systematic Review of Universal Influenza Vaccines in Clinical Trials during the 2010 Decade

“…Second, we searched clinical trials registered through ClinicalTrials.gov, which could potentially exclude some studies. There are other clinical trial databases such as EU Clinical Trials Register, however, the ClinicalTrials.gov database reports more accurate and updated information for clinical trials [ 144 ].…”

Results dissemination from clinical trials conducted at German university medical centres was delayed and incomplete

“…Completion dates are entered as expected dates and might not always reflect the actual completion dates. As registries are increasingly consulted as a key resource for health care information and for quality assessment of research practices it is important to improve their quality, accuracy and timeliness [30]. We published a more detailed commentary on how different measurement variables influence the assessment of publication rates elsewhere [31].…”