Incidence and phenotype of Inflammatory Bowel Disease from 2012-2013 across 9 countries in Asia: results from the 2012 access inception cohort

Abstract

BACKGROUND: The incidence of inflammatory bowel disease (IBD) in Asia was first reported in the 2011 ACCESS inception cohort. This study aims to validate the incidence reported in 2011 by including a second independent cohort from 8 of the participating countries in 2011 and Brunei to investigate the incidence of IBD in Asia in 2012. METHODS: Incident IBD cases diagnosed between April 1, 2012 and March 31, 2013 from 18 centres, 11 cities and 9 countries in Asia were enrolled. Data including demographics and disease phenotype were entered into a Web-based database (http://www.access-apibd.com/access/index.html). Disease location and behavior were classified according to the Montreal classification. RESULTS: A total of 325 IBD patients were identified including 189 (58%) ulcerative colitis (UC), 119 (37%) Crohn’s disease (CD), and 17 (5%) indeterminate colitis (IC). The crude overall annual incidence per 100,000 of IBD was 1.61 (95% confidence interval, CI, 1.44-1.79) in 2012 compared with 1.15 (95% CI, 1.25-1.51) in 2011. The highest incidence in Asia was in Guangzhou (3.86 per 100,000), Hong Kong (2.91 per 100,000) followed by Macau (2.60 per 100,000). Overall ratio of UC to CD in 2012 was similar to that of 2011 (1.57 vs. 1.69; p=0.211). There were more male than female patients in both years (59% vs 60%; p=0.773). Mean age of diagnosis was 40 years (±15.96) in 2011 and 42 years (±16.30; p=0.084) in 2012. Median time from symptom onset to diagnosis was 6 months (IQR 3-24) and 7 months (IQR 2-16), respectively, in 2011 and 2012 (p=0.958). Disease behavior (B1: 72.0%, B2: 9.9%, B3: 4.4%, perianal: 13.2%), location for CD (L1: 25.3%, L2: 25.3%, L3: 49.5%) and UC (E1: 30.9%, E2: 40.1%, E3: 28.9%) did not differ from previous year. Most CD patients were non-smokers (80.3%) whereas 9.9% were current smokers and 9.9% were ex-smokers. CONCLUSION: The incidence of IBD, UC to CD ratio and age of disease onset in the ACCESS 2012 cohort was not significantly different from that reported in the 2011 cohort. Disease phenotype was also similar over 2 years. The ACCESS inception cohort reflects the true incidence of IBD in Asia.