Authors of clinical trials reported individual and financial conflicts of interest more frequently than institutional and nonfinancial ones: a methodological survey
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BACKGROUND AND OBJECTIVE: Conflicts of interest (COIs) are increasingly recognized as important to disclose and manage in health research. The objective of this study was to assess the reporting of both financial and nonfinancial COI by authors of randomized controlled trials published in a representative sample of clinical journals. METHODS: We searched Ovid Medline and included a random sample of 200 randomized controlled trials published in 2015 in one of the 119 Core Clinical Journals. We classified COI using a comprehensive framework that includes the following: individual COIs (financial, professional, scholarly, advocatory, personal) and institutional COIs (financial, professional, scholarly, and advocatory). We conducted descriptive and regression analyses. RESULTS: Of the 200 randomized controlled trials, 188 (94%) reported authors' COI disclosures that were available in the main document (92%) and as International Committee of Medical Journal Editors forms accessible online (12%). Of the 188 trials, 57% had at least one author reporting at least one COI; in all these trials, at least one author reported financial COI. Institutional COIs (11%) and nonfinancial COIs (4%) were less commonly reported. References to COI disclosure statements for editors (1%) and medical writers (0%) were seldom present. Regression analyses showed positive associations between reporting individual financial COI and higher journal impact factor (odds ratio [OR] = 1.06, 95% confidence interval [CI] = 1.02-1.10), larger number of authors (OR = 1.10, 95% CI 1.02-1.20), affiliation with an institution from a high-income country (OR = 16.75, 95% CI 3.38-82.87), and trials reporting on pharmacological interventions (OR = 2.28, 95% CI 1.13-4.62). CONCLUSION: More than half of published randomized controlled trials report that at least one author has a COI. Trial authors report financial COIs more often than nonfinancial COIs and individual COIs more frequently than institutional COIs.