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. 2014 Apr 1;160(7):477-83.
doi: 10.7326/M13-0480.

Reporting discrepancies between the ClinicalTrials.gov results database and peer-reviewed publications

Daniel M Hartung, Deborah A Zarin, Jeanne-Marie Guise, Marian McDonagh, Robin Paynter, Mark Helfand

Reporting discrepancies between the ClinicalTrials.gov results database and peer-reviewed publications

Daniel M Hartung et al. Ann Intern Med. .

Abstract

Background: ClinicalTrials.gov requires reporting of result summaries for many drug and device trials.

Purpose: To evaluate the consistency of reporting of trials that are registered in the ClinicalTrials.gov results database and published in the literature.

Data sources: ClinicalTrials.gov results database and matched publications identified through ClinicalTrials.gov and a manual search of 2 electronic databases.

Study selection: 10% random sample of phase 3 or 4 trials with results in the ClinicalTrials.gov results database, completed before 1 January 2009, with 2 or more groups.

Data extraction: One reviewer extracted data about trial design and results from the results database and matching publications. A subsample was independently verified.

Data synthesis: Of 110 trials with results, most were industry-sponsored, parallel-design drug studies. The most common inconsistency was the number of secondary outcome measures reported (80%). Sixteen trials (15%) reported the primary outcome description inconsistently, and 22 (20%) reported the primary outcome value inconsistently. Thirty-eight trials inconsistently reported the number of individuals with a serious adverse event (SAE); of these, 33 (87%) reported more SAEs in ClinicalTrials.gov. Among the 84 trials that reported SAEs in ClinicalTrials.gov, 11 publications did not mention SAEs, 5 reported them as zero or not occurring, and 21 reported a different number of SAEs. Among 29 trials that reported deaths in ClinicalTrials.gov, 28% differed from the matched publication.

Limitation: Small sample that included earliest results posted to the database.

Conclusion: Reporting discrepancies between the ClinicalTrials.gov results database and matching publications are common. Which source contains the more accurate account of results is unclear, although ClinicalTrials.gov may provide a more comprehensive description of adverse events than the publication.

Primary funding source: Agency for Healthcare Research and Quality.

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Summary of trial selection
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