Neutrophil/Lymphocyte ratio an important marker of worse outcome in Covid-19: a cross-sectional study in a Brazilian population

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, is a pandemic with high morbidity and mortality. Several studies on the use of laboratory markers that can differentiate patients at high risk of death associated with COVID-19 or with an unfavourable course from mild to severe disease have been proposed recently. In this study, we evaluated hematological parameters of 1369 patients diagnosed with Covid-19 from a unique center of Brazil and correlated with disease severity. Patients were divided into two groups according to their clinical outcome: death or hospital discharge. The absolute number of neutrophils, lymphocytes, platelets  and the neutrophil/lymphocyte ratio were statistically significant between the two groups, with p<0.001. There was no statistical relevance between the platelet/lymphocyte ratio and the clinical evolution of the studied patients. Thus, our results reinforce the data described in previous studies that NLR can be an important marker of unfavourable clinical evolution in Covid -19.