Incidence and Phenotype of Inflammatory Bowel Disease From 13 Countries in Asia-Pacific: Results From the Asia-Pacific Crohn's and Colitis Epidemiologic Study 2011-2013

Abstract

Background: The Asia-Pacific Crohn's and Colitis Epidemiology Study, initiated in 2011, aimed to determine the incidence and phenotype of inflammatory bowel disease (IBD) in Asia-Pacific. We herein present incidence and phenotype data from 2011 through 2013 for 12 countries or areas in Asia (Brunei, China, Hong Kong, India, Indonesia, Macau, Malaysia, Philippines, Singapore, Sri Lanka, Taiwan, Thailand) and Australia. Methods: We performed a prospective, population-based study of IBD incidence in predefined catchment areas using a web-based database. New cases were diagnosed based on standard criteria and ascertained from multiple sources. Endoscopy, pathology, and pharmacy records were searched for completeness of case capture. Age-standardized incidence was calculated with 95% confidence interval (CI). Crude incidence in different regions within Asia was pooled together using a random effect model. Results: We identified 1,572 new IBD patients (2011-2012, n=419; 2012-2013, n=1,153; 131 from Australia) including 1,057 (67%) ulcerative colitis (UC) and 515 (33%) Crohn's disease (CD). The mean annual incidence for IBD per 100,000 was 1.68 (95% CI, 1.59-1.77) in Asia and 22.28 (95% CI, 18.48-26.71) in Australia. The three countries within Asia with the highest incidence per 100,000 was India (9.31; 95% CI, 8.38-10.31), China (Guangzhou) (3.30; 95% CI, 2.68-4.06) and Hong Kong (2.58; 95% CI, 2.20-3.03). Within five regions of China, IBD incidence varied from 0.49 to 3.30 per 100,000. Pooled incidence of UC and CD within East Asia (China, Macau, Hong Kong, Taiwan) was 1.12 (95% CI, 0.77-1.48) and 0.33 (95% CI, 0.17-0.49), respectively. Pooled incidence of UC and CD within South East Asia (Brunei, Malaysia, Singapore, Indonesia, Thailand, Philippines) was 0.38 (0.21-0.55) and 0.30 (95% CI, 0.22-0.38), respectively. Ratio of UC:CD was 2.21 in Asia and 0.64 in Australia. Median time from symptom onset to diagnosis was 3 months [interquartile range (IQR), 2-10] for UC and 7 months (IQR 2-19) for CD. Stricturing, penetrating and perianal CD at diagnosis was common (21%, 10% and 17%, respectively) in Asia. Conclusion: Robust large-scale comparative epidemiologic IBD data from newly industrialized countries are emerging. Incidence of IBD varies throughout Asia with a higher incidence in East than South-East Asia. Complicated CD at diagnosis remains prevalent in Asia. Emergence of IBD in Asia will result in the need for specific health-care resources.