Objectives: A novel coronavirus, Severe Acute Respiratory Syndrome Coronavirus 2, is causing the worldwide coronavirus disease 2019 (COVID-19) outbreak with high mortality . A unique finding among COVID-19 patients was a decline of eosinophil levels (eosinopenia). However, results from previous studies on the relationship between eosinopenia and disease severity were inconsistent . The objective of this study is to determine the relationship between eosinopenia and COVID-19 mortality as well as the clinical conditions that could potentially lead to mortality .
Methods: One hundred ninety patients diagnosed as moderate, severe, or critical COVID-19 at hospital admission were enrolled . Data collected from patients ’ medical records on the second day after hospital admission included medical histories, clinical symptoms, chest images of computed tomography (CT), laboratory examinations, and outcomes .
Results: Eosinophil levels were significantly lower in patients with critical disease, when compared to those with moderate and severe diseases . After controlled for confounding factors, i.e., age, gender, hypertension, coronary heart disease, diabetes, and chronic lung disease, a progressive decline of eosinophil levels was independently associated with mortality . Moreover, eosinophil levels significantly and positively correlated with platelet and D-dimer levels but significantly and inversely correlated with serum levels of urea, creatinine, aspartate aminotransferase, lactate dehydrogenase, and creatine kinase .
Conclusions: Eosinopenia, if progressively worsening, indicates that COVID-19 patients may progress to critical disease and have a significantly higher chance of mortality . Additionally, eosinopenia correlates with biomarkers of coagulation disorder and those of tissue damage in kidney, liver, and other tissues.