Outcomes of Clostridioides difficile Infection in Patients Treated With a Partial Versus Complete Course of Fidaxomicin

Background: High cost and inconsistent insurance coverages may necessitate partial completion of a fidaxomicin course with an alternative antibiotic. Objective: This study aimed to evaluate the impact of a partial versus complete course of fidaxomicin on Clostridioides difficile infection (CDI) treatment outcomes. Methods: This was a retrospective, multicenter cohort study of adult hospitalized patients with CDI treated with fidaxomicin from May 2022 through August 2023. Patients treated with a complete fidaxomicin course (≥20 doses) were compared with those treated with a partial fidaxomicin course (<20 doses). The primary outcome was 90-day CDI recurrence. Secondary outcomes were 30-day CDI recurrence, 90-day hospital readmissions, 90-day all-cause mortality, and hospital length of stay. Results: The study included 39 patients in the complete fidaxomicin and 11 patients in the partial fidaxomicin group. The partial fidaxomicin group observed a numerically higher rate of 90-day recurrence (12.8% vs 18.2%; P = .641). Similar patterns were observed for all secondary outcomes, except length of stay, which was longer in the complete fidaxomicin group (23.9 vs 9.8 days; P = .301). Among patients who completed treatment after discharge (62%), a gap in therapy of greater than 4 days was more frequent in the complete fidaxomicin group (2/22 vs 0/9; P = 1.000). Conclusions: Partial completion of a fidaxomicin course with an alternative antibiotic was associated with a numerically higher rate of CDI recurrence, readmission, and all-cause mortality. Small sample size limited the ability to detect statistically significant differences in these findings. Larger comparative effectiveness studies are needed.