Blood eosinophil count predicts disease severity in hospitalised community-acquired pneumonia

Background and objective Mortality in patients with community-acquired pneumonia (CAP) continues to be high. Predictors of disease severity are required to improve patient management. This study investigated blood eosinophil levels at hospital admission as an independent biomarker for predicting severity of CAP.

Methods We retrospectively reviewed≥18-year-old patient cases hospitalised with CAP from 2009 to 2020 using data from electronic health records of five German university hospitals from the Medical Informatics in Research and Care in University Medicine consortium. Patients were divided into an eosinopenia group (eosinophils≤50/µL) and non-eosinopenia group (eosinophils>50/µL). Comorbidities between groups were compared. Risk of death and mechanical ventilation were analysed in a multivariate model. Risk of sepsis, length of mechanical ventilation, length of stay in survivors, and time to in-hospital death were calculated in an univariate model.

Results Overall, 6,748 patient cases were included in the analysis. Of those, 4,060 cases had blood eosinophils≤50/µL, while 2,688 cases had eosinophils>50/µL. In the eosinopenia group, the prevalence of COPD (14.2%; p=0.004), myocardial infarction (1.6%; p=0.019), peripheral vascular disease (7.2%; p=0.008), and renal disease (21.7%; p < 0.0001) was lower compared with the non-eosinopenia group (16.8%, 2.5%, 9.0%, 25.9%, respectively). The prevalence of asthma, congestive heart failure, cerebrovascular disease, dementia, diabetes mellitus, and liver disease were not different between groups. In the eosinopenia group, in-hospital mortality (13.8%; p < 0.0001), risk of mechanical ventilation (19.2%; p < 0.0001), and risk of sepsis (7.5%; < 0.0001) were increased compared to the non-eosinopenia group (9.1%, 14.3%, and 5.0%, respectively). Length of stay in survivors was longer (8.41 days; p < 0.0001) in the eosinopenia group versus the non-eosinopenia group (7.64 days), while length of mechanical ventilation did not differ (p=0.152) between groups. Time to in-hospital death was shorter in the eosinopenia (6.73 days; p=0.001) versus non-eosinopenia group (8.92 days).

Conclusions Eosinopenia≤50/µL may be used as independent predictor of disease severity in CAP. Future prospective studies are required to confirm our results.

Publication History

Article published online:
01 March 2024