P818 Prevalence and Risk Factors of Comorbid Immune-Mediated Diseases in Patients with Inflammatory Bowel Disease: A Nationwide Population-Based Study in South Korea

Although an increased prevalence of other immune-mediated diseases (IMDs) has been reported in patients with inflammatory bowel disease (IBD), the association remains poorly defined in Asian populations with a low incidence of IBD. Risk factors for comorbid IMDs in patients with IBD are also unknown. Using the National Health Insurance claims data for the entire Korean population, we identified 54153 patients with IBD [17683 Crohn’s disease (CD) and 36 407 ulcerative colitis (UC)] from 2012 to 2016. Using logistic regression, the prevalence of various IMDs in patients with IBD were compared with age- and sex-matched controls. The immune diseases included in this study are those registered as rare intractable diseases for medical expenses support. We also identified risk factors for comorbid IMDs in IBD using a multivariable analysis. The overall IMD risk was higher in patients with CD [odds ratio (OR), 7.0; 95% confidence interval (CI), 5.8–8.4] and UC patients (OR, 4.3; 95% CI, 3.8–4.8), compared with controls. Patients with CD were at higher risk for the following IMDs: multiple sclerosis, rheumatoid arthritis, psoriatic arthropathy, vasculitis, lupus, dermatopolymyositis, systemic sclerosis, primary sclerosing cholangitis, autoimmune hepatitis, and ankylosing spondylitis. UC was associated with a higher prevalence of multiple sclerosis, rheumatoid arthritis, psoriatic arthropathy, vasculitis, lupus, primary sclerosing cholangitis, autoimmune hepatitis, and ankylosing spondylitis. In multivariable analysis, older age, female, CD, and severe disease were identified as independent risk factors for IMDs in patients with IBD. The prevalence of IMDs in Korean patients with IBD was higher than that of the general population. Understanding the risk factors for co-occurring IMDs facilitates early diagnosis and may contribute to improvement in the quality of care of patients with IBD. Prevalence of immune-mediated diseases in patients with IBD by phenotype of IBD