Undisclosed financial conflicts of interest among authors of American Society of Clinical Oncology clinical practice guidelines.

Background Clinical practice guidelines (CPGs) are crucial to the practice of evidence-based medicine. Declared author financial conflicts of interest (FCOIs) are common in CPGs and have been associated with endorsement of treatment. Less is known about undeclared FCOIs. Methods The American Society of Clinical Oncology (ASCO) website was searched to identify all CPGs for systemic therapy published between August 2013 and June 2018. Data on self-reported author FCOIs and funding sources were extracted. The Open Payments database was then searched to identify compensation to CPG authors. Concordance between declared and undeclared but verified FCOIs was assessed with Cohen's kappa. Results For 26 CPGs, 314 nonduplicate authors were identified; 184 of these authors (59%) disclosed FCOIs. Among the remaining 130 authors, data in Open Payments were unavailable for 71 authors (non-US residents or authors affiliated with a nonprofit organization). Among the 59 authors who declared no FCOIs and for whom Open Payments data were available, 55 (93%) had received payment from industry. The kappa value for agreement between disclosed and verified FCOIs was 0.092. Among the 243 authors with FCOIs verifiable via Open Payments, 239 (98%) received payment from industry. Thirty-four authors (62%) received more than $1000 in nonresearch funding, and 19 (35%) received more than $5000. Among the 52 first and last authors, 44 (85%) received payment from industry; 14 of these payments (32%) were not declared. Conclusions FCOIs among authors of ASCO CPGs are common and are not disclosed by a substantial proportion of authors with Open Payments data. Improved transparency of FCOIs should become standard practice among CPG authors. Professional societies and journal editors need to create a mechanism to verify self-reported FCOIs.