P643 Differences in Mucosal Distribution and Clinical Characteristics of Crohn's Disease 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 in Europe, North America and Australia compared to other regions of the world.
There is now evidence of increasing incidence in all populations worldwide. Studies from the UK, North America, Malaysia and Singapore 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 the South Asian immigrant 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 CD 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.
554 patients were recruited, 128 South Asians (SA) and 426 Caucasians (CAU). Males were more likely affected in the SA cohort versus CAU , which had the opposite trend. South Asians were most likely to be diagnosed with Colonic disease (L2) vs. CAU (50% vs. 24%), which was highly statistically significant (p= 1 X 10-6). Differences in luminal distribution between groups (L1-L4) were statistically significant between groups. Also differences in disease behaviour (B1,B2) were statistically significant but was not for B3 disease. South Asians were less likely to be diagnosed >40 years of age (A3) versus CAU (p=0.02). No statistical difference in positive family history or EIM's between groups. South Asians were less likely to need surgery versus CAU (29% vs. 58%), which was highly statistically significant (p<0.001).
There are significant differences in luminal distribution, age of diagnosis and need for surgery between groups. The fact that South Asians are less likely to need surgery suggests a less severe phenotype compared to Caucasians. These differences may represent difference in disease pathogenesis in particular genetic susceptibility or environmental factors. This information will help inform current and future genotype/phenotype correlations.