P674 Differences in Mucosal Distribution and Clinical Characteristics of Ulcerative Colitis in South Asians and Caucasians in the North of England
University of Manchester/Manchester Royal Infirmary, Department of Genetic Medicine/Department of Colorectal Surgery, Manchester, United Kingdom
Inflammatory bowel diseases (IBD) are inflammatory conditions that affect the gastrointestinal tract and may have extra intestinal manifestations. The two main subtypes are Crohn's disease (CD) and ulcerative colitis (UC). The aetiology remains elusive but the current paradigm is of an aberrant immune response as a result of an environmental factor(s) in a genetically susceptible individual. The incidence of IBD has traditionally been higher in Caucasian populations. There is now evidence of increasing incidence in all populations. Studies from the UK and North America have observed a 2-3 times higher incidence of IBD in South Asian immigrant populations compared to local cohorts. However, few studies have described the disease phenotype and luminal distribution in this population.
Ethics approval was obtained ref: O5/Q1407/274. Patients were recruited prospectively in 11 centres in the North Of England. Inclusion criteria were diagnosis of UC and age > 16 years. Exclusion criteria were diagnosis of IBDU or IDC and Age < 16 years. Information was collected from using a standard clinical proforma. Data was stored on and analysed on a FileMaker Pro database. Chi Squared analysis was used to compare groups.
In total 721 patients were recruited, 186 South Asians (SA) and 535 Caucasians (CAU). In the South Asian cohort males were more likely to be affected compared to Caucasians. South Asians had a younger average age of diagnosis 30 vs. 40 for Caucasians. There were differences in luminal distribution with South Asians more likely to have Extensive Colitis (45% vs. 26%) or Left sided colitis (42% vs. 22%) and Caucasians more likely to have Proctitis (13% vs. 52%). The differences in mucosal distribution between groups were highly statistically significant (p<0.001). There was no statistical difference in family history between groups with 21% of South Asians vs. 27% for Caucasians. There was no statistical difference in need for colectomy between groups (5% for SA vs. 3% for Caucasians). Also there was no statistical difference in the presence of EIM's 6% for SA vs. 5% for Caucasians.
There are significant differences in mucosal distribution and age of diagnosis between groups. South Asians had a younger age of onset and more extensive colitis, but the relatively low rate of colectomy and EIM's which suggest a less severe disease phenotype. In addition the younger age of onset and extensive disease in South Asians may influence risk of colorectal cancer in the future. These differences may represent differences in disease pathogenesis in particular genetic susceptibility or environmental factors. This information will help inform current and future genotype/phenotype correlations.