Recent trends in the epidemiology and clinical outcomes of inflammatory bowel disease in South Korea, 2010-2018.

BACKGROUND: Inflammatory bowel disease (IBD) was previously regarded as a Western disease; however, its incidence is increasing in the East. The epidemiology of IBD in Asia differs significantly from the patterns in the West.

AIM: To comprehensively investigate the epidemiology of IBD in South Korea, including its incidence, prevalence, medication trends, and outcomes.

METHODS: We analyzed claims data from the Health Insurance Review and Assessment Service and Rare and Intractable Diseases (RIDs), operated by the National Health Insurance Service of South Korea. Patients with IBD were identified based on the International Classification of Diseases, Tenth Revision, and RID diagnostic codes for Crohn's disease (CD) and ulcerative colitis (UC) from 2010 to 2018.

RESULTS: In total, 14498 and 31409 patients were newly diagnosed with CD and UC, respectively, between 2010 and 2018. The annual average incidence of CD was 3.11 cases per 105 person-years, and that of UC was 6.74 cases per 105 person-years. Since 2014, the incidence rate of CD has been stable, while that of UC has steadily increased, shifting the peak age group from 50-year-olds in 2010 to 20-year-olds in 2018. The CD and UC prevalence increased consistently over the study period; the use of 5-aminosalicylates and corticosteroids gradually decreased, while that of immunomodulators and biologics steadily increased in both CD and UC. The clinical outcomes of IBD, such as hospitalization and surgery, decreased during the study period.

CONCLUSION: The CD incidence has been stable since 2014, but that of UC has increased with a shift to a younger age at peak incidence between 2010 and 2018. IBD clinical outcomes improved over time, with increased use of immunomodulators and biologics.