P809 Increase of tuberculosis due to combination therapy in inflammatory bowel disease: a nationwide population-based study in Korea

Background Recent researches reported that inflammatory bowel disease (IBD) in Asia has become more prevalent. Since IBD is chronic inflammation disorder and its relapse is frequent, obtaining and maintaining remission is important. As our knowledge on the pathogenesis of IBD deepened, many immunosuppressants and biological agents were introduced and confirmed to be both safe and effective. However, biologics known as anti-tumour necrosis factor (anti-TNF) agents was reported to lose response over time in 23–46% of patients. Therefore, combination therapy adding immunomodulator drug such as azathioprine was introduced and showed better outcome by optimising biologic pharmacokinetics and minimising immunogenicity. Adversely, rates of tuberculosis are increased, but there is no large population data estimating and comparing these risk in combination therapy. Methods We used 2008–2016 data of the South Korean Health Insurance and Review Agency (HIRA), and odd ratio (OR) for tuberculosis in IBD patients who underwent anti-tumour necrosis factor (TNF) agent, azathioprine, or combination therapy. Results Between 2008 and 2016, 47,760 patients were newly diagnosed as IBD, 29,440 as UC and 15,320 as CD. We compared the risk of tuberculosis according to the medication divided into 5 groups; infliximab only, azathioprine only, combination of azathioprine and infliximab, azathioprine monotherapy and infliximab monotherapy, and azathioprine and infliximab whether simultaneously or separately. We also compared the risk between male and female. Hazard ratio of tuberculosis in infliximab monotherapy, azathioprine, and combination therapy in IBD patients were 1.132, 1.256, and 2.118, respectively. Conclusion Our study shows that Korean IBD patients are at risk for tuberculosis, and this results may highlight the importance of screening for tuberculosis in IBD patients.