Ethnicity and the risk of development of Crohn's disease of the ileal pouch.

BACKGROUND: A system-wide, multi-ethnicity study on Crohn's disease (CD) of the pouch, including Indian American (IA) patients has not been conducted.

AIM: To compare the frequency of subsequent development of CD of the pouch for African-American (AA), Hispanic-American (HA), IA and Caucasian patients with ulcerative (UC) undergoing ileal-pouch anal anastomosis (IPAA).

METHODS: In this historical cohort study from our Pouch Registry, patients with restorative proctocolectomy and IPAA for IBD with identifiable, self-declared racial background (i.e. AA, HA, IA or Caucasian) were included. Univariable and multivariable analyses were performed to identify risk factors for CD of the pouch.

RESULTS: The study included 235 patients: AA (N=26), HA (N=37), IA (N=22) and randomly selected Caucasian (N=150) controls. Greater number of HA and Caucasians had a history of smoking than IA (27.3% and 27.0% vs. 0; p=0.007). Caucasians and HA were also more likely to have a family history of IBD than IA or AA (25% vs. 27% vs. 5% vs. 4%; p=0.016.) IA less frequently had extensive colitis before colectomy than Caucasians (71.4% vs. 94.0%; p=0.004) and more frequently required anti-TNF biologics than HA (22.7% vs. 0; p=0.016). On multivariable logistic regression analysis, AA (odds ratio [OR]=10.1, 95% confidence interval [CI]: 1.03, 1365.8, p=0.004) and Caucasians (OR=11.1, 95% CI: 1.4, 1427.2, p=0.015) had a higher risk of developing CD of the pouch than IA. However, the event-free survival was not significantly different between the groups on Cox regression analysis, presumably due to the sample size.

CONCLUSION: Racial background may be associated with different risk for the development of CD of the pouch for patients with IBD undergoing IPAA.