P0972Prevalence of and risk factors for difficult-to-treat inflammatory bowel disease in Korean

Abstract Background Difficult-to-treat inflammatory bowel disease (DTT-IBD) describes patients who remain refractory despite sequential advanced therapies (ATs) with at least two different mechanisms of action. Data on its epidemiology in Asian populations remain limited. This study aimed to analyse the incidence of and risk factors for DTT-IBD in Korea. Methods We conducted a retrospective cohort study at a tertiary academic hospital, including 512 IBD patients treated with advanced therapies (ATs: biologics or small molecules). Statistical analyses included Kaplan–Meier survival curves, logrank tests, and Cox proportional hazards regression to identify clinical factors associated with DTTIBD. Results Of the cohort, 129 patients (25.2 %) met DTT criteria, defined by failed ATs with at least two different mechanisms. In ulcerative colitis (UC), the cumulative incidence of DTTIBD rose from 5.3 % at 1 year to 51.1 % at 10 years. In Crohn’s disease (CD), it increased from 0.4 % to 35.8 % over the same period. Patients who started ATs ≥2 years after UC diagnosis had a reduced risk of DTT (OR 0.503; 95 % CI, 0.302–0.836; p = 0.008). In CD, significant risk factors included stricturing/penetrating behaviour (OR 1.773, 95 % CI 1.067–2.945, p = 0.027), older age groups —specifically, patients aged 17–41 years (OR 3.314, 95 % CI 1.181–9.298, p = 0.023) and those older than 41 years (OR 3.846, 95 % CI 1.081–16.687, p = 0.038), and vedolizumab use as a first-line AT (OR 9.276; 95 % CI 4.590–18.743, p 0.001). Among CD patients undergoing a second surgery, cumulative DTT incidence reached approximately 50 % at 1 year, 86.4 % at 5 years and exceeded 93 % by 10 years postsurgery. Conclusion DTTIBD was present in around onequarter of IBD patients in Korean tertiary care. UC patients showed higher longterm DTT risk, while CD-related DTT was driven by disease behaviour, age, and therapy type. Particularly high postsurgical DTT incidence in CD underscores the need for proactive monitoring and early therapeutic strategies in this high-risk group. References: 1. Caron B, Habert A, Bonsack O, Camara H, Jeanbert E, Parigi TL, et al. Difficult-to-treat inflammatory bowel disease: Effectiveness and safety of 4th and 5th lines of treatment. United European Gastroenterology Journal. 2024;12(5):605–13. 2. Feng Z, Kang G, Wang J, Gao X, Wang X, Ye Y, et al. Breaking through the therapeutic ceiling of inflammatory bowel disease: dual-targeted therapies. Biomedicine 158:114174. 3. Parigi TL, D’Amico F, Abreu MT, Dignass A, Dotan I, Magro F, et al. Difficult-to-treat inflammatory bowel disease: results from an international consensus meeting. The Lancet Gastroenterology 8(9):853–9. 4. Wetwittayakhlang P, Ngampech S, Pattarakulniyom S, Lakatos PL. Objective Treatment Targets and Their Correlation with Patient-Reported Outcomes in Inflammatory Bowel Disease: A Real-World Study. Journal of Clinical Medicine. 2025;14(13):4733. Conflict of interest: Ms. Noh, Jung Hyun: No conflict of interest Lee, Ho-Kyoung: No conflict of interest Jun, Yu Kyung: No conflict of interest Choi, Jinju: No conflict of interest Choi, Yonghoon: No conflict of interest Shin, Cheol Min: No conflict of interest Park, Young Su: No conflict of interest Kim, Nayoung: No conflict of interest Yoon, Hyuk: Consultancy and/or advisory roles for AbbVie Korea, BMS Pharmaceutical Korea Ltd., Celltrion, Daewoong Pharm, Eisai Korea, Ferring Korea, Janssen Korea, Pfizer Korea, Samsung Bioepis, Takeda Korea and Yuhan Honoraria from AbbVie Korea, BMS Pharmaceutical Korea Ltd., Celltrion, Daewoong Pharm, Eisai Korea, Ferring Korea, Janssen Korea, Pfizer Korea, Samsung Bioepis, and Takeda Korea