RESUMO
BACKGROUND: Journals have increased disclosure requirements in recent years, in part to deter guest authorship. The prevalence of guest authorship among primary authors (first and last) in the current era of increased disclosure requirements is unknown. OBJECTIVES: Our aim was to examine the self-reported prevalence of guest authorship among primary authors from a sample of randomized clinical trials with and without industry funding and industry collaboration in the design, analysis or reporting of trials. DESIGN: Cross-sectional analysis of randomized, drug/device clinical trials with published details on the "Role of the Funding Source/Sponsor" published in high-impact biomedical journals between 1 December 2011 and 31 November 2012. Phase 1 or 2 trials, secondary trial analyses, and trials that were not listed on ClinicalTrials.gov were excluded. Primary guest authorship was defined, based on International Committee of Medical Journal Editors (ICMJE) criteria, when neither the first nor last author contributed to either of the following: 1) the design of the trial or the analysis/interpretation of data; or 2) drafting part or all of the manuscript. PARTICIPANTS: One hundred and sixty-eight randomized clinical trials that met inclusion criteria were included. MAIN OUTCOME MEASURES: We measured differences in the prevalence of guest authorship between trials with neither industry funding nor collaboration and 1) trials with industry funding without collaboration, and 2) trials with industry funding with collaboration. RESULTS: The overall prevalence of primary guest authorship was 6 % (10/168). Primary guest authorship was significantly more common in trials with industry funding with collaboration than in those with neither industry funding nor collaboration [13.2 % (10/76) vs. 0 % (0/39); p < 0.02]. Primary guest authorship did not differ between trials with industry funding without collaboration and trials with neither industry funding nor collaboration. CONCLUSIONS: Among a sample of randomized, drug/device clinical trials in high-impact biomedical journals, primary guest authorship was overall uncommon and occurred exclusively among trials with industry funding with collaboration.