P804 Temporal trends and the influence of regional and socioeconomic status on the incidence of inflammatory bowel disease: Using National Health Insurance Service Database in Korea, 2005–2017

Abstract

Abstract Background Well analysed data from the health insurance registry allows us detailed and various analyses of a nation-wide population study. In this study, we validate the diagnostic criteria of occurrence of new cases of Inflammatory Bowel Disease (IBD) using health insurance database and investigate the epidemiological features of IBD in Korea. Methods A population-based clinical data of patients with IBD in the Songpa-Kangdong district of Seoul was used as reference cases and the database of National Health Insurance Service from 2005 to 2015 was retrospectively reviewed to compare the diagnostic criteria. The most accurate criterion was applied to the entire database (2002–2017) with 3-year washout period for further assessment. Non-parametric statistics and p for trend analysis were used. Results The most accurate criteria of new cases of IBD was the combination of the experience of colonoscopy, IBD-specific medications at least 3 months and the International Classification of Disease 10th codes for Crohn’s disease (CD) and Ulcerative colitis (UC). With this criterion, new incident cases of IBD were 40,807 (14,183 CD, 26,624 UC) during the study period. The male to female ratio of age-adjusted incidence rate was 2.5:1 for CD and 1.4:1 for UC. Age- and sex-adjusted incidence per 100,000 population of CD and UC had increased from 1.4 and 3.6 (in 2005) to 2.2 and 4.2 (in 2017). Over 13 year period, the peak incidence of CD in both male and female was between 15 and 24 years of age without significant change while the peak incidence of UC was shifted from 55–64 years (in 2005–2008) to 25–34 years of age (in 2014–2017). There was a positive correlation between the socioeconomic status and incidence of IBD (p < 0.01). The standardised incidence rates of CD and UC in metropolitan areas were 2.4 and 4.3 per 100,000 population, while that in non-metropolitan areas were 2.0 and 3.8 per 100,000 population. The incidence rate of CD in metropolitan area was still significantly higher than in non-metropolitan area after the adjustment of socioeconomic status (p = 0.03). Conclusion The incidence of IBD in Korea has increased over the recent decade with the shift to younger age groups. The higher incidence in higher socioeconomic status and metropolitan areas gives a clue to the aetiology of this disease.