A new study has revealed discrepancies in completion status for trials listed on ClinicalTrials.gov and the EU Clinical Trials Register (EUCTR).
Researchers evaluated nearly 10,500 trials listed on both registries and found that roughly 16% of them were marked as “completed” on one registry and “ongoing” on the other.
Most of these (91%) were listed as “ongoing” on EUCTR but “completed” on ClinicalTrials.gov.
“Trial registries are important public documents,” said Ben Goldacre, of the University of Oxford in the UK.
“Doctors, researchers, and patients rely on the information that trialists post about their clinical trial. Concerningly, we now show that this data is commonly inaccurate.”
Goldacre and his colleague, Jessica Fleminger, also from the University of Oxford, reported these findings in PLOS ONE.
The researchers looked at 10,492 clinical trials that were registered on both ClinicalTrials.gov and EUCTR.
For most of these trials (83.8%, n=8794), completion status was the same on both registries. But there were 1698 trials (16.2%) that were listed as “completed” on one registry and “ongoing” on another.
A majority of the discrepant trials (90.5%, n=1536) were “ongoing” on EUCTR and “complete” on ClinicalTrials.gov.
Overall, 43.1% (4530/10,492) of dual-registered trials were listed as “ongoing” on EUCTR, and 33.9% of these (1536/4530) were listed as “completed” on ClinicalTrials.gov.
Thirty percent (3156/10,492) of dual-registered trials were marked as “ongoing” on ClinicalTrials.gov, and 5.1% (162/3156) of these were marked as “completed” on EUCTR.
Goldacre and Fleminger said it is unclear whether researchers, registry owners, or both are responsible for these errors. Regardless, researchers identifying discrepancies should request clarifications from the trialists, and registry owners should undertake simple cross-checks of data to ensure that completion status is accurate.