S1726 Comparing Outcomes of Clostridioides difficile Infection Treated With Oral Vancomycin vs Fidaxomicin for an Initial Episode in Patients With Inflammatory Bowel Disease

Introduction: Clostridioides difficile infection (CDI) presents a unique challenge in patients (pts) with inflammatory bowel disease (IBD), who experience higher recurrence rates and morbidity than the general population. While both oral vancomycin (OV) and oral fidaxomicin (OF) are recommended first-line therapies for CDI, guidelines have suggested that OF is associated with lower rates of recurrent CDI (rCDI) in the non-IBD population. Direct comparative data on rCDI rates between these agents in IBD pts remains unexplored. This study aimed to compare rates of rCDI in IBD pts treated with OV vs OF for their first infection. Methods: Using the TriNetX dataset (5/14/05-5/14/25), we identified pts with IBD, defined by ≥1 International Classification of Diseases-10 code for ulcerative colitis (K51) or Crohn’s disease (K50), and a CDI diagnosis (International Classification of Diseases-10 A04.72 or International Classification of Diseases-9 008.45) occurring after IBD diagnosis. Inclusion required a prescription for OV (RxNorm 11124) or OF (RxNorm1111103) within 5 days of first CDI diagnosis. Cohorts were matched for age, sex, race, and immunosuppressant use. rCDI was defined by either a positive stool NAAT or a diagnosis code for rCDI (A04.71) occurring 2-8 weeks after initial CDI. Secondary outcomes included colectomy rates and rates of either oral or intravenous (IV) corticosteroids at 3-12 months after initial CDI episode. Binary variables were analyzed using the Chi-Square test. Results: After matching, 1,135 IBD pts (mean age 52 ± 21.0 years, 57.4% female) were included in each treatment group. There was no significant difference in rates of rCDI between IBD pts treated with OV (n = 143) as compared to OF (n = 166); (HR: 0.834; 95% CI, 0.667–1.043; P = 0.557) 2-8 weeks after the initial CDI. Secondary analyses demonstrated no difference in systemic corticosteroids use or colectomy rates between groups during the 3-12 months follow up period. Conclusion: Among IBD pts treated for initial CDI, OV and OF were associated with comparable rates of rCDI, systemic corticosteroid use, and need for colectomy. These findings suggest that both agents are reasonable first-line treatment options in this population. Prospective studies that account for IBD subtype, treatment response, long term complications, and adverse drug events are needed to guide individualized therapy.