LAUSR

Background The causes of chronic antibiotic refractory pouchitis (CARP) and pouch failure in inflammatory bowel disease (IBD) patients remain unknown. Our previous small study showed peripouch fat area measured by MRI was associated with pouchitis. Aims To explore the relationship between peripouch fat area on CT imaging and pouch outcomes. Methods This is a historical cohort study. Demographic, clinical, and radiographic data of IBD patients with abdominal CT scans after pouch surgery between 2002 and 2017 were collected. Peripouch fat areas and mesenteric peripouch fat areas were measured on CT images at the middle pouch level. Results A total of 435 IBD patients were included. Patients with higher peripouch fat areas had a higher prevalence of CARP. Univariate analyses demonstrated that long duration of the pouch, high weight or body mass index, the presence of primary sclerosing cholangitis or other autoimmune disorders, and greater peripouch fat area or mesenteric peripouch fat area were risk factors for CARP. Multivariable analyses demonstrated that the presence of primary sclerosing cholangitis or autoimmuned disorders, and greater peripouch fat area (odds ratio [OR] 1.031; 95% confidence interval [CI] 1.016–1.047, P  < 0.001) or mesenteric peripouch fat area were independent risk factors for CARP. Of the 435 patients, 139 (32.0%) had two or more CT scans. Multivariable Cox proportional hazard analyses showed that “peripouch fat area increase ≥ 15%” (OR 3.808, 95%CI 1.703–8.517, P  = 0.001) was an independent predictor of pouch failure. Conclusions A great peripouch fat area measured on CT image is associated with a higher prevalence of CARP, and the accumulation of peripouch fat is a risk factor for pouch failure. The assessment of peripouch fat may be used to monitor the disease course of the ileal pouch.