P762 Risk of Infection After Acute Severe Ulcerative Colitis in East Asia and Australia/New Zealand: AOCC and ANZIBDC collaboration study

Abstract

Abstract Background Infection is one of the concerns in the treatment of inflammatory bowel disease, and advanced age and immunosuppressants are known to be risk factors for infection. However, there has been no studies on infection after acute severe ulcerative colitis (ASUC) and its associated factors. The aim of this study was to investigate infection and associated factors in ASUC patients, as well as differences in infection risk between regions of East Asia and Australia/New Zealand (ANZ). Methods We retrospectively analyzed patients with ASUC diagnosed according to Truelove Witt criteria from January 2015 to September 2022. We identified the overall incidence of infection and related risk factors, and then analyzed the differences by two regions. Results A total of 676 ASUC patients (329 in East ASIA, 347 in ANZ) were enrolled. Overall infections within 1 year after ASUC occurred in 65 patients (9.6%). Clostridioides difficile (C. diff) infection (17/65, 26%), CMV colitis (14/65, 21%), and pneumonia (7/65, 10%) were most common infections. Risk factor associated with infection was combination therapy with anti-TNF agent and thiopurine at discharge (hazard ratio [HR] 5.225, 95% confidential interval [CI] 2.469-11.059, P<0.001). The group with infections exhibited worse outcomes, including a higher readmission rate (39.3% vs. 92.2%, p < 0.001), readmission due to ulcerative colitis (UC) (16.3% vs. 31.3%, p = 0.004), UC-related mortality (0.9% vs. 9.6%, p < 0.001), and overall mortality during the follow-up period (1.1% vs. 13.8%, p < 0.001, Table 1). In comparative analysis between East Asia and ANZ, there was no difference in the incidence of infection (7.6% vs 11.5%, p=0.083) and infection related mortality (1% vs 0.3%, p=1.000) within 1 year after ASUC. CMV colitis (10/25, 40%) and C. difficile infection (6/25, 24%) were common in East Asia while C.difficile infection (11/40, 27%) and skin infections (7/40 17%) occurred frequently in ANZ. The risk factors for infection in East Asia were anti TNF at discharge (HR 3.684, 95% CI 1.434-9.465, P=0.007) and CMV infection (HR 3.587, 95% CI 1.136-11.333, P=0.03), but the risk factors for infection in ANZ were combination therapy with anti TNF and thiopurine at discharge. (HR 7.911, 95% CI 3.397-11.333, P=<0.001, Figure 1). Conclusion The incidence of infection within 1 year after ASUC is 9.6%, and combination therapy of anti-TNF and thiopurine at discharge is a risk factor. Infections were associated with poor prognosis including mortality. There was no difference in the incidence and mortality rates of infections between East Asia and ANZ while the types of infections and related risk factors were different.