P-1005. Real-World Effectiveness of Fidaxomicin in Preventing Recurrence of Initial Community-Associated Clostridioides difficile Infection

Background In 2021, ISDA guidelines recommended fidaxomicin over vancomycin as first line treatment of Clostridioides difficile infection (CDI) based on clinical trials showing reduced recurrence. However, real-world effectiveness studies of fidaxomicin primarily in hospitalized and high-risk populations showed mixed results. Evidence of fidaxomicin effectiveness for community associated (CA) CDI in outpatient settings remains limited. The study aim is to evaluate the real-world effectiveness of fidaxomicin for initial CA-CDI. Methods We used data from population-based surveillance of CDI in Monroe County, NY (2020-2024), as part of the CDC Emerging Infections Program. CA CDI was defined as a first episode with no healthcare exposure in the prior 12 weeks. Adults (≥ 18 years) who completed an uninterrupted course of oral therapy were included. Clinical data, inpatient treatment and recurrence at 8 weeks and 90 days were abstracted from medical records. Recurrence rates were compared between fidaxomicin and vancomycin treated groups using bivariate and multivariable log-binomial regression models. Results Among 1193 cases with initial CA-CDI,146 (12.2%) received fidaxomicin and 1047 (87.8%) vancomycin. Groups were similar in sex, comorbidities and prior PPI/H2 blocker use. Cases receiving fidaxomicin were more likely to be aged 40-59 (32% vs. 23.3%). In hospital treatment was comparable (20.5% vs. 18.8%). Recurrence at 8 weeks and 90 days was 8.2% and 8.9% for fidaxomicin, and 14.9% and 17.8% for vancomycin, respectively (p < 0.05). Crude models showed that vancomycin was associated with a higher risk of 8-week recurrence (RR: 1.81; 95% CI: 1.03–3.18) and 90-day recurrence (RR: 2.00; 95% CI: 1.17–3.41). After adjustment, the risk remained elevated for 8-week recurrence (RR: 1.72; 95% CI: 0.98–3.03) and 90-day recurrence (RR: 1.89; 95% CI: 1.10 – 3.23). Conclusion Fidaxomicin was associated with a lower recurrence rate than vancomycin in CA-CDI with a statistically significant benefit at 90 days. These findings support the current IDSA guidelines and highlight the real-world advantage of fidaxomicin for initial CA-CDI management. Disclosures All Authors: No reported disclosures