What researchers report in their journal articles and to ClinicalTrials.gov don't always match up, according to a new study in the Journal of the American Medical Association from Yale University School of Medicine researchers.
The Yale researchers, led by Joseph Ross, sifted through nearly 100 clinical trials registered with ClinicalTrials.gov and published in 19 high-impact journals, including JAMA, the Lancet, and the New England Journal of Medicine. For each trial, they compared whether the published account was concordant, discordant, or could not be compared to its ClinicalTrials.gov information.
From this, the researchers found that nearly every study had at least one discrepancy between the two.
For instance, the trials reported some 156 primary efficacy endpoints, 85 percent of which were reported in both spots, but 9 percent were only described at ClinicalTrials.gov and 6 percent only in publications. Meanwhile, secondary efficacy endpoints were more disparate with 30 percent described in both spots, 20 percent only at ClinicalTrials.gov and 50 percent only in publications.
Further, even if the endpoints were described in both ClinicalTrials.gov and in the journal article, they were not always the same or presented in the same manner.
"We found important discrepancies between the results reported in ClinicalTrials.gov and the published results," Ross tells News@JAMA. "We don’t know which is right. There were lots of end points reported in [one] source that weren’t reported in the other."
Ross notes that there are a number of possible explanations for the discrepancies, including choosing endpoints to make the results look better or typographical errors.