Purpose: Conflict of interest (COI) may compromise, or have the appearance of compromising, a researcher's judgment or integrity in conducting or reporting research. We sought to assess time trends of COI and funding statement reporting in the critical care literature.
Methods: PubMed was searched by using Medical Subject Headings and the appropriate corresponding keywords: "INTENSIVE CARE UNIT" or "ICU" as a major topic. Four years in a 15-year time period (2001-2016) were arbitrarily chosen and one study month was randomly selected for each study period. Studies published during the selected months were included in the analysis.
Results: Three hundred and seventy-four studies were evaluated, including five reviews (1.3%) and ten randomized clinical trials (RCTs) (2.7%). COI statements were available in 65% of the studies and 8% had declared COI. COI statement rate, declared COI and funding statements increased over time, while the number of authors affiliated with industry and the discordance between the lack of COI statement and affiliation with industry decreased. Declared COI were more frequent in 2011-2016 as compared to 2001-2010 (OR 4.06; 95% CI 1.15-25.79) and in the higher quartile of a journal's impact factor (OR of 16.73; 95% CI 3.28-306.20). Surprisingly, focus of the study, country of the first author and/or endorsement of the study by a trial group were not associated with COI statements.
Conclusion: Our study suggests COI reporting to have been unintuitive to most investigators and unreliable before ICMJE statements, and that strong incentives are needed to implement adequate reporting of COI.
Keywords: Bias; Bibliometrics; Conflicts of interest; Disclosure/statistics and numerical data; Editorial policies; Journal impact factor; Periodicals as topic/standards.