Epidemiological trend in inflammatory bowel disease in Taiwan from 2001 to 2015: a nationwide populationbased study.

Background/Aims: Incidences of inflammatory bowel diseases (IBDs), ulcerative colitis (UC), and Crohn's disease (CD), have been increasing in Asia. In this study, we report the relevant clinical characteristics and determined the epidemiological trend of IBD in Taiwan from 2001 to 2015.

Methods: A retrospective study was conducted to analyze data recorded from January 2001 through December 2015 in the registered database compiled by the National Health Insurance and provided by the Ministry of Health and Welfare, Taiwan.

Results: A total of 3,806 patients with catastrophic IBD illness were registered from 2001 to 2015 in Taiwan (CD, 919; UC, 2,887). The crude incidence of CD increased from 0.17/100,000 in 2001 to 0.47/100,000 in 2015, whereas that of UC increased from 0.54/100,000 in 2001 to 0.95/100,000 in 2015. The prevalence of CD increased from 0.6/100,000 in 2001 to 3.9/100,000 in 2015, whereas that of UC increased from 2.1/100,000 in 2001 to 12.8/100,000 in 2015. The male-to-female ratio in the study sample was 2.19 for CD and 1.62 for UC. The median age of those registered with CD was lower than that of those registered for UC: 38.86 and 44.86 years, respectively. A significantly greater increase in CD incidence rate was identified among 20 to 39-year-old compared with other age groups.

Conclusions: Using Taiwan's nationwide insurance database, we determined that the number of patients with CD increased more rapidly during the study period than the number of patients with UC, especially among age 20 to 39-year-old, resulting in a decreased UC-to-CD ratio.