Early Pouchitis Is Associated With Crohn's Disease-like Pouch Inflammation in Patients With Ulcerative Colitis

Background: Despite the initial diagnosis of ulcerative colitis (UC), approximately 10% to 20% of patients develop Crohn's disease-like pouch inflammation (CDLPI) after restorative proctocolectomy (RPC) with ileal pouch anal anastomosis (IPAA). The aim of this study was to evaluate whether early pouchitis, defined as pouchitis within the first year after IPAA, is a predictor of CDLPI. Methods: This was a retrospective cohort analysis of patients with UC or IBD unclassified (IBDU) who underwent RPC with IPAA at Mount Sinai Hospital between January 2008 and December 2017. The primary outcome was development of CDLPI. Predictors of CDLPI were analyzed via univariable and multivariable Cox regression models. Results: The analytic cohort comprised 412 patients who underwent at least 1 pouchoscopy procedure between 2009 and 2018. Crohn's disease-like pouch inflammation developed in 57 (13.8%) patients a median interval of 2.1 (interquartile range, 1.1-4.3) years after surgery. On univariable analysis, older age at colectomy (hazard ratio [HR], 0.97; 95% CI, 0.95-0.99) was associated with a reduced risk of CDLPI; although early pouchitis (HR, 2.43; 95% CI, 1.32-4.45) and a greater number of pouchitis episodes (HR, 1.38; 95% CI, 1.17-1.63) were associated with an increased risk. On multivariable analysis, early pouchitis (HR, 2.35; 95% CI, 1.27-4.34) was significantly associated with CDLPI. Time to CDLPI was significantly less in patients who developed early pouchitis compared with those who did not (P =. 003). Conclusion: Early pouchitis is significantly associated with subsequent CDLPI development and may be the first indication of enhanced mucosal immune activation in the pouch.