Demographics and Phenotypic Behavior of Inflammatory Bowel Disease in South Asians Living in the United States

Abstract

The incidence and prevalence rates of inflammatory bowel disease (IBD) have increased in South Asian populations. There are no data on the IBD phenotype and behavior in South Asian patients living in the U.S. Our objective was to determine the demographics, disease type, behavior and phenotypic variation of South Asian patients with IBD. Adult South Asian patients with IBD were identified from a patient care database between January 2008 and June 2012 in the IBD Center at Baylor College of Medicine, a tertiary care center. Clinical and demographic data were abstracted from systematic review of electronic medical records using a standardized abstraction form. Additional data were obtained via telephone interview pertaining to patient birth place, parents place of birth, first generation immigration status, time spent in the U.S., family history of IBD, and dietary pattern. We identified 47 South Asian patients with IBD; 26 (55%) with ulcerative colitis (UC) and 21 (45%) with Crohn's disease (CD). The male/female ratio was 1.2 for UC and 1.1 for CD. The median age at diagnosis of both UC and CD was 28 years (range 11-66). The mean duration of disease was 7 years (range 1-18) for UC and 6.5 years (range 1-16) for CD. Six patients (23%) with UC and 3 patients (14%) with CD had a positive family history of IBD. One patient (4%) with UC, and 3 patients (14%) with CD, had a prior or current history of smoking. Thirty four patients; 18 (69%) with UC and 16 (76%) with CD were born outside the US (1st generation). The mean time spent in the US prior to disease manifestation or diagnosis was 18 ± 9.3 years for UC and 16.7 ± 8.9 years for CD. Approximately 25% of IBD patients were vegetarians with an equal percentage in both UC and CD. Fourteen patients (54%) with UC had pancolitis, 11 (42%) had left sided disease and 1 (4%) had proctitis. Three patients (12%) required a colectomy. Twelve patients (57%) with CD had ileocolonic involvement (57%), 6 (29%) had ileal disease and 3 (14%) had colonic disease. Ten (48%) patients with CD had stricturing and/or penetrating disease of which, 4 (40%) required bowel resection. Eleven (23%) patients (23%) had extra-intestinal manifestations, primarily joint involvement. No patient was diagnosed with colorectal cancer. Eleven patients (42%) with UC and 14 patients (67%) with CD were maintained on immunomodulator or biologic therapy. South Asian patients were more likely to have UC than CD. There was a slight male predominance for both UC and CD. The median age at diagnosis for CD was similar to that reported previously in Caucasian populations, but higher for UC. There was a high positive family history of IBD as well as presence of extra-intestinal manifestations. Disease extent and location was predominantly pancolitis in UC and ileocolonic in CD.