Eosinopenia is associated with worse outcomes in hospitalized patients with Clostridioides difficile infection in South Korea

Background: Emerging evidence suggests that eosinopenia is a significant predictor of mortality in Clostridioides difficile infection (CDI). However, the role of eosinopenia as a predictive marker in patients with CDI is unclear in the Asia-Pacific region. We evaluated the relationship between laboratory values, including peripheral eosinophil counts, and adverse events, including mortality, in hospitalized patients with CDI. Methods: We performed a retrospective cohort study of hospitalized adult patients (≥18 years old) with CDI at Seoul St. Mary's Hospital, a tertiary care academic hospital, between January 2017 and May 2021. Patients with CDI who were treated with vancomycin for at least 72 h were enrolled. Results: In total, 303 patients were included in the study (101 patients with eosinopenia and 202 patients without eosinopenia). Patients in the eosinopenia group had a significantly higher rates of composite of inpatient all-cause mortality or colectomy within 60 days of CDI diagnosis (33.7% vs 19.8%, p = 0.012) than those without eosinopenia. Inpatient all-cause mortality rate was significantly higher, and duration of intensive care unit stay after CDI diagnosis significantly lower in the eosinopenia group. There were no differences between the two groups in colectomy rate, clinical cure rate, recurrence rate, length of hospital stay after CDI diagnosis. In the multivariate analysis, eosinopenia (odds ratio, 2.21; 95% confidence interval [CI], 1.13–4.33; p = 0.021) were significantly associated with composite outcome. The area under the receiver operating characteristic curve for eosinopenia predicting composite outcome was 0.59, for Infectious Diseases Society of America/Society for Healthcare Epidemiology of America severity criteria 0.59, for ATLAS score 0.62, and for neutrophil-to-lymphocyte ratio 0.56. Conclusion: Eosinopenia was associated with worse clinical outcomes in hospitalized patients with CDI, although of limited diagnostic accuracy.