Fidaxomicin for Initial Episode of

Introduction: Fidaxomicin is a narrow-spectrum, nonabsorbable antibiotic recommended as first-line therapy for nonfulminant Methods: We conducted a retrospective cohort study of Clalit Health Services adults with a first laboratory-confirmed CDI between January 2013 and December 2023. Patients with prior CDI were excluded. The primary outcome was a composite of recurrence, 90-day mortality, and colectomy, which were compared between the fidaxomicin and vancomycin groups. Secondary outcomes included each component individually. Results: The study included 11 204 patients with a first CDI episode, of whom 2362 were immunocompromised. The fidaxomicin group had a significantly lower recurrence rate compared to vancomycin (8% vs 17%, Conclusions: ICHs treated with fidaxomicin had significantly lower recurrence rates and fewer complications compared to vancomycin. Despite assumptions, ICHs had recurrence rates similar to immunocompetent patients, highlighting the role of comorbidities and treatment choices. Our findings support fidaxomicin as a preferred first-line option in select ICHs and underscore the need for individualized management strategies to improve outcomes in this high-risk population.