Predictive value of eosinophil count on COVID-19 disease progression and outcomes, a retrospective study of Leishenshan Hospital in Wuhan, China.

Background: The potential protective role of eosinophils in the COVID-19 pandemic has aroused great interest, given their potential virus clearance function and the infection resistance of asthma patients to this coronavirus. However, it is unknown whether eosinophil counts could serve as a predictor of the severity of COVID-19. Methods: A total of 1004 patients with confirmed COVID-19 who were admitted to Leishenshan Hospital in Wuhan, China, were enrolled in this study, including 905 patients in the general ward and 99 patients in the ICU. We reviewed their medical data to analyze the association between eosinophils and intensive care unit (ICU) admission and death. Results: Of our 1004 patients with COVID-19, low eosinophil counts/ratios were observed in severe cases. After adjusting for confounders that could have affected the outcome, we found that eosinophil counts might not be a predictor of intensive care unit (ICU) admission. In 99 ICU patients, 58 of whom survived and 41 of whom died, low eosinophil level was an indicator of death in patients with severe COVID-19, with a cutoff value of 0.04 × 109/L for the prediction of death. Conclusion: Our research revealed that a low eosinophil level was a predictor of death in ICU patients rather than a cause of ICU admission.