Incidence and natural course of inflammatory bowel disease in Korea, 2006-2012: a nationwide population-based study

Although a rising trend in the incidence of inflammatory bowel disease (IBD) in Asia has been recognized, national-level, population-based studies are lacking. In this study, we investigate the epidemiological features and natural course of IBD in Korea, including incidence, bowel resection rates, survival, and cause of death. We analyzed the Rare Intractable Disease registration and Health Insurance Review and Assessment Services claims database, which include information on every patients with IBD diagnosed through uniform criteria from 2006 to 2012. Twenty-seven thousand four hundred nineteen patients with IBD newly diagnosed from 2006 to 2012 were traced to bowel resection, survival, and cause of death. During study period, mean annual incidence for ulcerative colitis was 4.6 per 10 and for Crohn's disease (CD) was 3.2 per 10. Bowel resection rates at 1 and 5 years for patients with ulcerative colitis were 0.8% and 2.1%, respectively, and for patients with CD were 5.0% and 9.1%, respectively. Survival of patients with CD was lower than that of the general population, whereas patients with ulcerative colitis had similar survival. In patients with CD, mortality for colon cancer, lung cancer, and gastrointestinal disease was significantly increased compared with general population. Incidence of IBD found in our study is the highest in East Asia. Lower bowel resection rates and higher survival compared to those of Western nations suggest that the natural course of IBD may be different between East Asia and the West.