# Clinical and Pharmacoeconomic evaluation of Fidaxomicin in patients over 65 years of age and immunocompromised patients with recurrent and refractory Clostridioides difficile infection

## TL;DR

This study compares fidaxomicin and vancomycin for treating Clostridioides difficile infection in older and immunocompromised patients, finding better clinical outcomes with fidaxomicin despite higher drug costs.

## Contribution

The study provides new clinical and pharmacoeconomic evidence for fidaxomicin use in older and immunocompromised patients with recurrent or refractory CDI.

## Key findings

- Fidaxomicin showed significantly higher symptom reduction on day 10 compared to vancomycin.
- Fidaxomicin had lower CDI recurrence rates than vancomycin.
- Overall treatment costs were comparable despite higher drug costs for fidaxomicin.

## Abstract

Recurrent or refractory Clostridioides difficile infection (CDI) often affects older and immunocompromised patients, posing clinical and economic challenges. While fidaxomicin has shown lower recurrence rates than vancomycin in the general population, evidence in this population remains limited.

This retrospective, multicentre case-control study compared patients aged > 65 years or immunocompromised patients receiving fidaxomicin (case group) with those treated with vancomycin (control group) for recurrent or refractory CDI. A microcosting approach was used to assess direct treatment costs.

A total of 344 patients were included (172 per group). Compared to the control group, the fidaxomicin group presented a significantly higher rate of symptom reduction on day 10 (n = 163, 95% vs. n = 147, 86%; p = 0.004) and lower CDI recurrence rates (n = 36, 21% vs. n = 63, 37%; p = 0.001). While the mean CDI treatment costs per patient were significantly higher in the fidaxomicin group (p < 0.001), the hospitalisation and overall treatment costs were comparable (€19,898, 95% CI €16,151-€23,645 vs. €20,469, 95% CI €16,837-€24,101, p = 0.811; €17,798, 95% CI €14,620-€20,975 vs. €17,300, 95% CI €14,199-€20,400, p = 0.840). Key cost drivers were hospitalisation, intensive care unit treatment, and severe initial CDI.

Despite higher drug acquisition costs of fidaxomicin, overall treatment costs were comparable between the two groups with better clinical outcomes in patients treated with fidaxomicin.

Not applicable.

The online version contains supplementary material available at 10.1186/s12879-026-12611-4.