Date of Award

January 2015

Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Joseph S. Ross

Subject Area(s)

Medicine, Public policy

Abstract

In 2007, the FDA Amendments Act expanded requirements for ClinicalTrials.gov, a public clinical trial registry maintained by the U.S. National Library of Medicine, mandating results reporting within 12 months of trial completion for all FDA regulated drugs. We compared clinical trial results reported on ClinicalTrials.gov with corresponding published articles. We conducted a cross-sectional analysis of clinical trials published from July 1, 2010 through June 30, 2011 in high impact journals (impact factor 10 or higher) that were registered and reported results on ClinicalTrials.gov. We compared trial results reported on ClinicalTrials.gov and within published articles for the following: cohort characteristics, trial intervention, primary and secondary efficacy endpoint definition(s) and results, and adverse events. Of 95 included clinical trials registered and reporting results on ClinicalTrials.gov, there were 96 corresponding publications, among which 95 (99%) had at least one discrepancy in reporting of trial details, efficacy results, or adverse events between the two sources. When comparing reporting of primary efficacy endpoints, 132 (85%) were described in both sources, 14 (9%) were described only on ClinicalTrials.gov, and 10 (6%) only within articles. Results for 30 of 132 (23%) primary endpoints could not be compared because of reporting differences between the two sources (e.g., tabular versus graphics); among the remaining 102, reported results were discordant for 21 (21%), altering interpretations for 6 (6%). When comparing reporting of secondary endpoints, 619 (30%) were described in both sources, 421 (20%) were described only on ClinicalTrials.gov, and 1049 (50%) only within articles. Results for 228 of 619 (37%) secondary endpoints could not be compared; among the remaining 391, reported results were discordant for 53 (14%). Among published clinical trials that were registered and reported results on ClinicalTrials.gov, nearly all had at least one discrepancy in reported results, including a fifth among primary endpoints. Our findings question the accuracy of both sources and raise concerns about the usefulness of results reporting to inform clinical practice and future research efforts.

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