Eosinopenia and prognosis in severe community-acquired pneumonia

Eosinopenia has been reported as a marker of severity in infections, but its prognostic value in patients with severe community-acquired pneumonia (CAP) admitted to the intensive care unit (ICU) is unclear. We retrospectively analyzed 496 patients with severe CAP admitted to the ICU and stratified them according to the presence of eosinopenia on admission. We compared clinical characteristics, laboratory data, microbiological etiology, treatment, complications, and outcomes between groups. Independent factors associated with 30-day mortality were identified using multivariable Cox regression. Discriminative performance of eosinophil count, severity scores (CRB-65, CURB-65, PSI), and a modified CURB-65 incorporating eosinopenia (CURB-65Eos) were assessed using ROC curves. Eosinopenia was present in 163/496 patients (33%). Age and most comorbidities were similar between groups. Compared with non-eosinopenic patients, eosinopenic patients had lower leukocyte, neutrophil, and lymphocyte counts and more frequent viral or polymicrobial infections. They more often required invasive mechanical ventilation (58% vs. 45%, p = 0.009) and developed pleural effusion (30% vs. 19%, p = 0.008). In-hospital and 30-day mortality were higher in the eosinopenia group (21% vs. 13%, p = 0.036; 20% vs. 12%, p = 0.022). In the predefined multivariable Cox model, eosinopenia was independently associated with increased 30-day mortality (HR 1.95; 95% CI 1.19 to 3.20; p = 0.008). Eosinophil counts alone showed poor discrimination for 30-day mortality (AUC 0.562), while established severity scores performed moderately. CURB-65Eos showed a numerical but nonsignificant improvement over CURB-65. Eosinopenia is common in patients with severe CAP admitted to the ICU and is independently associated with increased 30-day mortality. It may serve as a simple and inexpensive biomarker for the early identification of high-risk patients and could complement established severity scores to support closer monitoring and earlier escalation of care.