Financial Conflicts of Interest in Clinical Practice Guidelines: A Systematic Review

OBJECTIVE: To systematically evaluate the prevalence of disclosed and undisclosed financial conflicts of interest (FCOI) among clinical practice guidelines (CPGs). METHODS: In this systematic review, we ascertained the prevalence and types of FCOI for CPGs from January 1, 1980, to March 3, 2019. The primary outcome was the prevalence of FCOI among authors of CPGs. FCOI disclosures were compared between medical subspecialties and societies producing CPGs. RESULTS: Among the 37 studies including 14,764 total guideline authors, 45% had at least one FCOI. The prevalence of FCOI per study ranged from 6% to 100%. More authors had FCOI involving general payments (39%) compared with research payments (29%). Oncology, neurology, and gastroenterology had the highest prevalence of FCOI compared with other medical specialties. Among the 8 studies that included the monetary values in US dollars of FCOI, average payments per author ranged from $578 to $242,300. Among the 10 studies that included data on undisclosed FCOI, 32% of authors had undisclosed industry payments. CONCLUSION: There are numerous FCOI among authors of CPGs, many of which are undisclosed. Our study found a significant difference in FCOI prevalence based on types of FCOI and CPG sponsor society. Additional research is required to quantify the implications of FCOI on clinical judgment and patient care.