P425 Clinical Characteristics of Steroid-Dependent Ulcerative Colitis Patients after Acute Severe Ulcerative Colitis Treatment in East Asia and Australia/New Zealand: AOCC and ANZIBDC collaboration study

Background Intravenous steroid therapy (IVS) is the main initial treatment for acute severe ulcerative colitis (ASUC). The study aimed to assess corticosteroid dependency after treating ASUC and to explore potential differences between East Asian and Caucasian populations within the steroid-dependent group. Methods Patients from East Asia (China, Japan, South Korea, and Taiwan) and Australia/New Zealand diagnosed with ASUC based on the Trulove and Witts criteria from January 2015 to September 2022 were retrospectively included in the study. We specifically chose individuals responsive to intravenous corticosteroid treatment and divided them into two groups based on steroid dependency. "Steroid dependency" was defined as the inability to reduce steroid medication to a dosage below 10 mg/d (equivalent to prednisolone) within three months of initiating steroid treatment or experiencing a relapse within three months of discontinuing steroid therapy. Patients with a history of biologics or small molecules and those currently receiving them were excluded. Results Among 861 patients with ASUC (430 from East Asia and 431 from Australia/New Zealand), 626 received initial IVS, and 381 showed steroid response. Among these steroid responders, 102 patients (26.7%) were classified as steroid-dependent with no significant difference between East Asians and Caucasians (28.3% vs. 24.1%, p=0.44). For 1 year after ASUC, the colectomy rate (7.8% vs. 2.9%, p=0.04) and ASUC relapse rate (18.6% vs. 10.2%, p=0.03) were higher in the steroid-dependent than non-dependent group. For the management of steroid dependency, East Asians mainly repeated steroid treatment (60.9%), while Caucasians mostly switched to infliximab (57.1%). In the Cox regression analysis of 3-year follow-up data for the steroid-dependent group, Caucasians showed a significant increase in colectomy rates (adjusted hazard ratio [aHR] 1.59, 95% confidential interval [CI] 1.12-2.25, p<0.01) compared to East Asians. Additionally, relapse rates increased in Caucasians (aHR 1.37, 95% CI 1.13-1.65, p<0.01), while relapse rates decreased in thiopurine users (aHR 0.32, 95% CI 0.12-0.87, p=0.03). Conclusion Around one-fourth of patients with ASUC who initially responded to IVS became steroid-dependent. East Asians showed a more favorable prognosis compared with Caucasian in this steroid-dependent group.