Prognostic value of neutrophil and lymphocyte counts and neutrophil/lymphocyte ratio for predicting death in patients hospitalized for COVID-19

COVID-19 primarily affects the respiratory system and can cause changes in other systems. Early identification of patients with a higher potential for complications is critical to provide the best possible treatment to reduce the disease's lethality. This study aimed to analyze the behavior of hematologic biomarkers in predicting mortality in patients hospitalized with COVID-19. This retrospective cohort study used data from the medical records of patients hospitalized with COVID-19 between March and August 2020 in two referral hospitals for treatment of the disease in the city of Cuiabá (in the state of Mato Grosso, Brazil). Clinical and laboratory characteristics related to cardiovascular involvement and death during hospitalization were evaluated. Neutrophils, lymphocytes, and monocytes, as well as the neutrophil-to-lymphocyte ratio (NLR) and the monocyte-to-lymphocyte ratio (MRL), were used as potential biomarkers of death. A total of 199 patients were included (male: 113; mean age: 51.4 years). Leukocyte, neutrophil, and lymphocyte counts showed a statistically significant association with death, as did NLR and MRL. Satisfactory accuracy in predicting death was observed for leukocyte, neutrophil, lymphocyte, NLR, and MLR counts. The hematologic biomarkers studied may be useful for prognosticating hospitalized patients for the possibility of death from COVID-19.