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.