The Presence of Primary Sclerosing Cholangitis is Associated with a Lower Risk for Crohnʼs Disease of the Ileal Pouch

Abstract

Purpose: Concomitant primary sclerosing cholangitis (PSC) was shown to increase the risk for chronic pouchitis. However, the association between concomitant PSC and Crohn's disease (CD) of the ileal pouch has NOT been studied. Clinically, we seldom encountered patients who had both CD of the pouch and PSC. The aim of this study was to investigate the association between PSC and occurrence of CD of the pouch. Methods: Consecutive inflammatory bowel disease (IBD) patients undergoing proctocolectomy with ileal pouch-anal anastomosis (IPAA) seen in our subspecialty Pouchitis Clinic from 2002-2011 were studied. Cases consisted of patients with CD of the ileal pouch. The association between the presence of concomitant PSC and CD of the ileal pouch was evaluated. Results: A total of 1,289 patients met the inclusion criteria, including 246 (19.1%) with CD of the ileal pouch, diagnosed based on a combined assessment of clinical presentation, endoscopy, histology, radiography and examination under anesthesia. Seven-hundred eleven patients (55.2%) were male. The mean age at the time of diagnosis of IBD and at pouch surgery was 25.4±12.3 years and 35.4±13.9 years, respectively. Preoperative diagnosis of IBD was ulcerative colitis in 1190 (92.5%) patients, indeterminate colitis in 76 (5.9%) and Crohn's disease in 20 (1.6%). There were 67 PSC patients (5.2%). Concomitant PSC was significantly less common in patients with CD of the ileal pouch (N=62, 5.9%) than those without (N=5, 2.0%) (P=0.013). In the multivariate analysis, the presence of concomitant PSC was shown be negatively associated with the risk for the development of CD of the ileal pouch, with an odds ratio (OR) of 0.375 (95% confidence interval [CI]: 0.128-0.872, P=0.020). However, no significant difference in terms of the distribution of phenotypes of CD of the ileal pouch between patients with and without concomitant PSC was identified (P=0.369). Conclusion: The presence of PSC is inversely associated with the development of CD of the ileal pouch, in contrast to the consistent finding in the literature that PSC is associated with an increased risk for chronic pouchitis. The opposite impact of the liver disease on the two chronic inflammatory conditions of the pouch suggests that CD of the pouch and chronic pouchitis may have different etiopathogenetic pathways.Table 1: Risk factors associated with CD of the ileal pouch: multivariate logistic regression analysisTable 2: PSC and phenotypes of CD of the ileal pouch