Impact of surgeon caseload, case mix, and team dynamics on gender disparities in cholecystectomy outcomes

Abstract Introduction Previous research suggests that female surgeons achieve better outcomes in various procedures, but the underlying mechanisms remain unclear. This study aimed to identify factors explaining gender disparities in cholecystectomy outcomes between male and female surgeons. Method This population-based cohort study used data from the Swedish Registry of Gallstone Surgery (GallRiks). It included all patients who underwent cholecystectomy in Sweden between 2007 and 2019, with a subgroup (2017–2019) analysed for case mix. The association between surgeon gender and outcomes was assessed, considering caseload, case mix, team composition, and surgeon-patient gender dynamics. Binomial logit models with cluster-robust standard errors and mixed model analysis were used. Result The analysis included 150,509 cholecystectomies performed by 2,555 surgeons (849 female, 1,706 male). Female surgeons had fewer complications across all experience and volume categories. The gender disparity in bile duct injuries was most notable among male surgeons with <3 years of experience (RR 1.77, 95%CI 1.30–2.40). After adjusting for case mix, male surgeons had higher risks of surgical complications (RR 1.28, 95%CI 1.12–1.45), bile duct injuries (RR 1.63, 95%CI 1.01–2.62) and total complications (RR 1.10, 95%CI 1.03–1.19), but shorter operating times. Teams with only male surgeons had the highest complication rates. Female patients experienced the best outcomes when treated by female surgeons. Discussion Female surgeons were associated with more favourable cholecystectomy outcomes. These differences persisted after accounting for caseload, case mix and team composition. Inexperienced male surgeons had a higher risk of bile duct injury, underscoring the importance of rigorous mentorship during the early years of practice.