Risk factors for fistulizing disease of the pouch after ileal pouch-Anal anastomosis for ulcerative colitis

PURPOSE: Long-term data on the risk factors for fistulizing disease (FD) after ileal pouch-anal anastomosis (IPAA) for ulcerative colitis are limited. This study aimed to identify the predictors of FD after ileostomy closure and evaluate the impact of FD on pouch failure. METHODS: We reviewed 374 patients who underwent mucosal restorative proctocolectomy with handsewn IPAA between 2004 and 2022. Cox proportional hazards regression and log-rank tests were used to assess the FD-free survival and risk factors. RESULTS: After excluding 59 patients, 315 patients were analyzed. FD developed in 20 (6.3%) of these patients. Multivariate analysis showed that a monthly prednisolone (PSL) dose ≥ 450 mg before IPAA and chronic pouchitis were independent risk factors for FD (odds ratio [OR] 2.96, 95% CI: 1.15-7.64, p = 0.025; OR 3.85, 95% CI: 1.52-9.78, p = 0.0045). Patients with PSL ≥ 450 mg or chronic pouchitis had significantly poorer FD-free survival (p = 0.0004 and p = 0.0002, respectively). Pouch failure occurred more frequently in patients with FD than in those without FD (30.0% vs. 1.0%; p < 0.0001). CONCLUSIONS: High steroid exposure before IPAA and chronic pouchitis were significant predictors of FD, which strongly increased the risk of pouch failure.