P0542Characteristics, risk factors and outcomes for Crohn’s disease of the pouch: a single-centre retrospective cohort study

Abstract Background Despite ongoing advancements in medical management, up to 10-30% of patients with ulcerative colitis will require a colectomy, either as an elective or emergent procedure. Commonly, there is subsequent bowel restoration with creation of an ileal pouch-anal anastomosis (IPAA). Disease course can be complicated following an IPAA, with the potential development of mechanical, neoplastic and inflammatory problems, including Crohn’s disease of the Pouch (CDP). We aimed to determine the characteristics, risk factors and outcomes for CDP in an inflammatory bowel disease (IBD) cohort at a provincial quaternary referral centre. Methods We performed a single-centre retrospective cohort study including consecutive patients from 2005-2017 who underwent IPAA for IBD. Data was extracted from the electronic medical record for patient sex, age, colectomy indication, initial IBD diagnosis, revision of diagnosis to CDP (defined as the presence of a perianal or other fistula that developed at least 12 months after the final stage of IPAA surgery, stricture of the pouch body or prepouch ileum, and/or prepouch ileitis), and need for pouch excision. Odds ratios and means were calculated. Patients with an alternative indication other than IBD for IPAA were excluded. Results 297 patients who underwent an IPAA for IBD were included, of whom 63 patients (21.21%) had their diagnosis revised to CDP. The mean duration from pouch creation to CDP diagnosis was 125.6 months. Gender was not a predictor of CDP (OR 1.22, 95%CI: 0.69-2.14). Patients with a diagnosis of CDP had a significantly younger mean age at time of colectomy (28.05 vs. 34.35 years, p = 0.0001) compared to those without CDP. The phenotypic characteristics of patients with CDP was fistulising in 36.5% (23/63), stricturing in 12.7% (8/63), and 52.4% (33/63) had prepouch ileitis. A history of emergent (versus elective) colectomy was significantly associated with the development of CDP (OR 2.49, 95%CI: 1.24-5.00). For biologic treatment of CDP, 34.8% (23/63) were on infliximab, 6.3% (4/63) on upadacitinib, 11.1% (7/63) on Risankizumab, 28.6% (18/63) on vedolizumab, 17.5% (11/63) on adalimumab, and 4.8% (3/63) on ustekinumab. CDP was significantly associated with pouch excision (OR 4.56, 95%CI: 1.90-10.91). 19.0% (12/63) patients with CDP required pouch excision in our cohort, while the overall pouch excision rate was 7.7% (23/297). Conclusion The development of CDP was diagnosed in ∼20% of our centre’s IPAA cohort. CDP was associated with a history of emergent colectomy and with a younger age at time of colectomy. CDP was a predictor for pouch excision. Future analyses will consider additional predictive factors for both the development of CDP and response to advanced therapies. Conflict of interest: Dr. Nguyen, Bachviet: No conflict of interest Dhaliwal, Balkaran: No conflict of interest Johal, Niall: No conflict of interest Sadat Afjeh, Niki: No conflict of interest Rosenfeld, Greg: No conflict of interest Bressler, Brian: Personal Fees: Janssen, Abbvie, Takeda, Pfizer, Alimentiv, Pendopharm, Genentech, Merck, CSL Other: Stock Options: Qu Biologics, Dova Health Intelligence Williams, Astrid-Jane: No conflict of interest