S1547 Clinical Outcomes of Fidaxomicin vs Vancomycin in Treating Clostridioides difficile Infections in Patients With Inflammatory Bowel Disease

Introduction: Patients with inflammatory bowel disease (IBD) are particularly vulnerable to Clostridioides difficile infection (CDI). Recent society guidelines recommend fidaxomicin as the preferred standard-of-care (SOC) treatment for CDI over vancomycin. This study aims to compare the efficacy of treatment and clinical outcomes of IBD patients with CDI following SOC treatment with either vancomycin or fidaxomicin. Methods: We identified adult patients with IBD [Ulcerative Colitis (UC) or Crohn’s Disease (CD)] with new or recurrent CDI who were treated with either vancomycin or fidaxomicin at an academic medical center between January 2022 to December 2024. Baseline demographics, IBD clinical characteristics, comorbidities, and prior CDI history were obtained. Cox proportional hazard analysis assessing time to a composite of CDI recurrence and IBD severity outcomes within 1 year from end of CDI treatment was performed. IBD severity outcomes included change in IBD therapy, new corticosteroid therapy, IBD surgery, IBD-related hospitalization, IBD-related ER visits, toxic megacolon, colon perforation, and septic shock. Results: We identified 182 patients with IBD whose CDI was treated with either vancomycin (n = 136) or fidaxomicin (n = 46). Patient characteristics were similar across treatment groups except prior CDI infections were higher in fidaxomicin compared to vancomycin (50.0% vs 29.4%, P = 0.01) and the length of CDI treatment was shorter in fidaxomicin compared to vancomycin group (median 11 vs 23 days, P < 0.01). CDI recurrence within 1-year among all IBD patients was 3.9%, with 2.2% and 4.4% (P = 0.68) in groups treated with fidaxomicin and vancomycin, respectively. IBD patients treated with fidaxomicin had numerically fewer outcomes related to new corticosteroid therapy, IBD surgery, IBD related hospitalization and ER visits compared to patients treated with vancomycin but were not statistically significant. There were no significant associations between type of SOC therapy (aHR = 1.47; P = 0.19) or hospitalization due to CDI (aHR = 1.64; P = 0.05) and risk of 1-year CDI recurrence and IBD severity outcomes (P = 0.15). Conclusion: Vancomycin and fidaxomicin are efficient in treating CDI in patients with IBD. Fidaxomicin was associated with numerically lower recurrence and adverse IBD outcomes, however, this association was not significant after adjusting for IBD and CDI confounders. Further studies with large cohorts are needed to verify these findings.