Evaluation of Financial and Nonfinancial Conflicts of Interest and Quality of Evidence Underlying Psoriatic Arthritis Clinical Practice Guidelines: Analysis of Personal Payments From Pharmaceutical Companies and Authors’ Self‐CitationRate in Japan and the United States

To assess financial conflicts of interest (COI) and nonfinancial COI among psoriatic arthritis (PsA) clinical practice guideline (CPG) authors in Japan and the US, and to evaluate the quality of evidence and strength of recommendations of PsA CPGs. We performed a retrospective analysis using payment data from major Japanese pharmaceutical companies and the US Open Payments Database from 2016 to 2018. All authors of PsA CPGs issued by the Japanese Dermatological Association (JDA) and American College of Rheumatology (ACR) were included. Of 23 CPG authors in Japan, 21 (91.3%) received at least 1 payment, with a combined total of $3,335,413 between 2016 and 2018. Regarding 25 US authors, 21 (84.0%) received at least 1 payment, with a combined total of $4,081,629 during the same period. The 3‐year combined mean ± SD payment per author was $145,018 ± $114,302 in Japan and $162,825 ± $259,670 in the US. A total of 18 authors (78.3%) of the JDA PsA CPG and 12 authors (48.0%) of the ACR PsA CPG had undisclosed financial COI worth $474,663 and $218,501, respectively. The percentage of citations with at least 1 CPG author relative to total citations was 3.4% in Japan and 33.6% in the US. In sum, 71.4% and 88.8% of recommendations for PsA in the JDA and ACR were supported by low or very low quality of evidence. More rigorous cross‐checking of information disclosed by pharmaceutical companies and self‐reported by physicians and more stringent and transparent COI policies are necessary.