Secondary prophylaxis for Clostridioides difficile infection for patients on non- Clostridioides difficile antibiotics: A retrospective cohort study

Objectives Recurrent Clostridioides difficile infection (CDI) poses healthcare challenges and morbidity. Preventing recurrence with prophylactic oral CDI antibiotics lack consensus. Methods We used data from the largest healthcare provider in Israel to identify all adults aged 18 years or older diagnosed with a first episode of CDI (Index CDI) between February 2018 and December 2022 and subsequently received a non-CDI antibiotic within 2-8 weeks. Patients who received a concurrent prophylactic CDI antibiotic constituted the CDI prophylaxis group. Multivariable Cox proportional hazard regression models were used to examine the association of secondary CDI prophylaxis with CDI recurrence according to the severity of the index CDI (primary objective) and with 4- and 8-week all-cause mortality (secondary objective). Results A total of 434 eligible patients were included. Among them, 327 did not receive CDI antibiotic prophylaxis, while 107 did. CDI antibiotic prophylaxis was associated with a significant risk reduction of CDI recurrence with an adjusted HR of 0.51 (95% CI, 0.27-0.97). The magnitude of the association was modified by the severity of the index CDI episode (P for interaction 0.0182). Specifically, the HR for recurrence was 0.163 (95% CI 0.045-0.593) for non-severe CDI, and 1.242 (95% CI 0.524-2.946) for severe CDI. No significant association was found between CDI antibiotic prophylaxis and 4- 8 weeks mortality. Conclusion Secondary prophylaxis with CDI antibiotics appears to be associated with a reduced risk of recurrence in patients with previous non-severe CDI episode. Further studies are needed to confirm this finding.