Evaluation of financial conflicts of interest and quality of evidence in Japanese gastroenterology clinical practice guidelines

Background Clinical practice guidelines assist healthcare professionals in providing evidence‐based care. However, pharmaceutical companies' financial interests often influence guideline content. This study aimed to elucidate the magnitude of financial ties among Japanese gastroenterology guideline authors and the pharmaceutical industry. Methods Using pharmaceutical company disclosed payment data, we evaluated financial conflicts of interest (COI) among Japanese Society of Gastroenterology guideline authors between 2016 and 2021. Additionally, we assessed the evidence quality supporting guideline recommendations and associations with financial COI. Finally, we evaluated author COI management during guideline development against global standards. Results Overall, 88.2% (231/262) of guideline authors received a median of $12 968 (interquartile range [IQR]: $1839–$70 374) in payments between 2016 and 2019 for lectures, writings, and consulting. Chairpersons received significantly higher payments (median: $86 444 [IQR: $15 455–$165 679]). Notably, 41 (15.6%) authors had undeclared payments exceeding declaration requirements. Low or very low‐quality evidence supported 41.0% of recommendations. There was a negative association between the median 4‐year payment per author and the proportion of recommendations based on low‐quality evidence (odds ratio: 0.966 [95% confidence interval [95% CI]: 0.945–0.987], P = 0.002) and positive association with moderate‐quality evidence (odds ratio: 1.018 [95% CI: 1.011–1.025], P