Evolution of surgical risk in Crohn's disease: impact of the biologic therapy era on time to first surgery in a Bosnian tertiary referral center.

OBJECTIVE Contemporary surgical risk data from Southeastern Europe are limited. We assessed cumulative surgical probabilities, independent predictors of surgery, and the impact of evolving therapeutic strategies in a Bosnian tertiary referral cohort. METHODS This retrospective cohort study included 153 patients with Crohn's disease treated at University Clinical Center Tuzla between 2009 and 2023. Calendar-period analysis estimated contemporary surgical risk, while natural-history analysis characterized progression from diagnosis. Sequential multivariable Weibull regression identified independent predictors of time to first surgery. RESULTS Cumulative probabilities of surgery at 1, 5, and 10 years were 3, 11, and 34%, respectively. Five factors independently reduced surgical risk. Early biologic therapy showed the largest effect (hazard ratio: 0.22, 95% confidence interval: 0.07-0.73; P = 0.014), followed by colonic location (hazard ratio: 0.37, 95% confidence interval: 0.16-0.81; P = 0.014), inflammatory phenotype (hazard ratio: 0.53, 95% confidence interval: 0.32-0.85; P = 0.011), diagnosis during the biologic era (≥2017; hazard ratio: 0.56, 95% confidence interval: 0.35-0.88; P = 0.013), and early azathioprine initiation (hazard ratio: 0.61, 95% confidence interval: 0.40-0.93; P = 0.022). Sequential modeling confirmed additive protective effects of therapeutic exposures. Early surgery was associated with lower subsequent biologic use than no early surgery (27.5 vs. 81.4%; P < 0.001). CONCLUSION Surgical risk in this Southeastern European cohort aligns with Western estimates. Colonic location and inflammatory phenotype were intrinsic protective factors, whereas early azathioprine, early biologic therapy, and biologic-era diagnosis independently reduced surgical risk. These findings support early combined therapy for high-risk patients.