Neutrophil/Lymphocyte Ratio and C-Reactive Protein in Patients with COVID-19: Correlations in Deceased and Surviving Patients

COVID-19 is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) associated with inflammatory process activation. Among the elements involved in the inflammatory process are leukocytes and cytokine production. Various studies have determined the importance of the neutrophil-to-lymphocyte ratio (NLR) in different inflammatory processes. C-reactive protein (CRP) is involved in several infectious processes as a marker of inflammation. This study aims to determine the values of NLR and CRP in COVID-19 patients and controls and to determine these values in COVID-19 survivors and deceased patients. Overall, during COVID-19, lymphocyte counts, NLR, and CRP values were significantly increased.Furthermore, it was observed that during the disease, there were more positive correlations between the different inflammatory parameters studied than between the controls. The results show that surviving patients had increased lymphocyte counts and CRP content compared to deceased patients; however, the latter presented the highest NLR values and the lowest lymphocyte values, establishing a prognostic value of severe evolution. The number of significant correlations observed in surviving and deceased patients was similar. This study suggests the importance of leukocytes and CRP in COVID-19 and a possible predictive value for the severe evolution of NLR in the disease.