Trend and Geographic Variation in Incidence and Prevalence of Inflammatory Bowel Disease in Regions Across China: A Nationwide Employee Study Between 2013 and 2016

Background Incidence and prevalence rates and trends of inflammatory bowel disease (IBD) in China remain largely unknown. Objective This study aimed to estimate the nationwide prevalence and incidence of IBD and identify its noticeable trends in China between 2013 and 2016. Methods We conducted a population-based analysis using data from the National Urban Employee Basic Medical Insurance database. Patients with at least three claims of IBD diagnosis were identified. A Joinpoint regression model was used to analyze the annual percent change (APC) of the age-standardized incidence and prevalence. Results The age-standardized prevalence of Crohn's disease (CD) increased from 1.59/100,000 in 2013 to 3.39/100,000 ( p < 0.05) in 2016, and that of ulcerative colitis (UC) increased from 8.72/100,000 to 17.24/100,000 ( p < 0.05) during the period, with a UC/CD ratio of 5.09 in 2016. The age-standardized incidence of CD varied between 0.82/100,000 and 0.97/100,000 ( p = 0.9), whereas that of UC slightly increased from 4.54/100,000 to 4.85/100,000 ( p = 0.7). The eastern region of China had the highest incidence and prevalence, and the western region had the lowest rates, in both UC and CD, showing an east-to-west gradient. Conclusion The incidence and prevalence of IBD in most urban regions in China had an emerging trend over the study period, and an east-to-west gradient was observed, which indicated a greater burden in eastern China. Efforts to improve prevention strategies and promote awareness of IBD are needed, particularly in young men who are at higher risk for CD.