Increased age, neutrophil-to-lymphocyte ratio (NLR) and white blood cells count are associated with higher COVID-19 mortality

OBJECTIVE: Coronavirus disease 19 (COVID-19) caused by the highly pathogenic SARS-CoV-2, was first reported from Wuhan, China, in December 2019. The present study assessed possible associations between one-month mortality and demographic data, SpO(2), underlying diseases and laboratory findings, in COVID-19 patients. Also, since recent studies on COVID-19, have focused on Neutrophil-to-lymphocyte ratio (NLR) as an independent risk factor of the in-hospital death and a significant prognostic biomarker of outcomes in critically ill patients, in this study, we assessed predictive potential of this factor in terms of one-month mortality. METHODS: Patients admitted to Imam Reza hospital, affiliated to Mashhad University of Medical Sciences, Mashhad, Iran, from March to June 2020, with positive RT-PCR results for SARS-CoV-2, were included in this study. Kaplan-Meier survival analysis and Cox proportional hazard model were used to respectively estimate one-month mortality since admission and determine factors associated with one-month mortality. RESULTS: In this retrospective cohort study, 219 patients were included (137 men and 82 women (mean age 58.2 ± 16 and 57 ± 17.3 years old, respectively)). Hypertension, ischemic heart disease and diabetes were respectively the most common comorbidities. Among these patients, 63 patients were admitted to the ICU and 31 deaths occurred during one-month follow-up. With respect to mean peripheral capillary oxygen saturation (SpO(2)), 142 patients had SpO(2) ≤ 90%. Based on our analysis, older age and increased Neutrophil-to-lymphocyte ratio (NLR), and White blood cells (WBC) count were associated with increased risk of one-month mortality. Patients with SpO(2) ≤ 90% had a 3.8-fold increase in risk of one-month death compared to those with SpO(2) > 90%, although the difference did not reach a significant level. CONCLUSION: Multivariate analysis introduced age, WBC count, and NLR as predictors of one-month mortality in COVID-19 patients.