There is a high prevalence of financial conflicts of interest (COI) between physicians and industry.
To conduct a systematic review with meta-analysis examining the completeness of self-reported financial COI disclosures by physicians, and identify factors associated with non-disclosure.
MEDLINE, Embase and PsycINFO were searched for eligible studies up to April 2020 and supplemented with material identified in the references and citing articles.
Data were independently abstracted by two authors. Data synthesis was performed via systematic review of eligible studies and random-effects meta-analysis.
The proportion of discrepancies between physician self-reported disclosures and objective payment data was the main outcome. The proportion of discrepant funds and factors associated with non-disclosure were also examined.
40 studies were included. The pooled proportion of COI discrepancies at the article level was 81% (range: 54%–98%; 95% CI 72% to 89%), 79% at the payment level (range: 71%–89%; 95% CI 67% to 89%), 93% at the authorship level (range: 71%–100%; 95% CI 79% to 100%) and 66% at the author level (range: 8%–99%; 95% CI 48% to 78%). The proportion of funds discrepant was 33% (range: 2%–77%; 95% CI 12% to 58%). There was high heterogeneity between studies across all five analyses (I 2=94%–99%). Most undisclosed COI were related to food and beverage, or travel and lodging. While the most common explanation for failure to disclose was perceived irrelevance, a median of 45% of non-disclosed payments were directly or indirectly related to the work. A smaller monetary amount was the most common factor associated with nondisclosure.