Risk stratification is required to improve the management of pouchitis with ulcerative colitis (UC) patients who undergo ileal pouch-anal anastomosis (IPAA). Recently, the colectomy risk score (CRS) has been used to assess UC severity and predict the need for surgery. We explored whether the CRS predicted pouchitis in patients with UC who underwent IPAA. This retrospective study included 168 UC patients who underwent IPAA. Pouchitis was diagnosed according to the pouchitis disease activity index. The primary endpoint was the cumulative incidence of pouchitis. The risk factors for pouchitis using preoperatively obtained data, including the CRS, were investigated. Based on their CRS, patients were assigned to low- (scores 0–3), intermediate- (scores 4–6), and high-risk (scores 7–9) groups. The incidence of pouchitis was estimated using the Kaplan–Meier curve. CRS validity was assessed using the Cox proportional hazards model. During the median 7.2 (interquartile range [IQR] 2.8–11.1) years’ follow-up, 37 (28.5%) patients were diagnosed with pouchitis. Patients with pouchitis had significantly higher CRS than patients without pouchitis (median 7.0; IQR, 4.0–7.0 vs median 5.0; IQR, 3.0–7.0). The cumulative incidences of pouchitis in the low-, intermediate-, and high-risk groups were 10.3%, 18.3%, and 36.1% at 5 years, respectively. Thus, the incidence trended to increase significantly as CRS increased. Multivariate analysis revealed high-risk CRS status was an independent predictor of pouchitis (hazard ratio: 18.03; 95% confidence interval 1.55–210.05). CRS is useful in risk stratification for the development of subsequent pouchitis in patients with UC undergoing IPAA.
