Neutrophil to lymphocite ratio and inflammatory biomarkers as prognostic factors amongst patients with COVID-19: A prospective cohort study

Abstract

Introduction: Patients with COVID-19 can develop respiratory failure requiring treatment with invasive mechanical ventilation (IMV) and death. It is important to have clinical predictors of these outcomes. Objetives: To establish the diagnostic accuracy of neutrophil to lymphocyte ratios (NLr) in predicting the need of IMV and survival amongst patients with COVID-19 and to compare this accuracy with other laboratory tests. Methodology: Prospective cohort study of hospitalized patients with a SArS-CoV-2 infection confirmed by rT-PCr. Clinical, demographic and laboratory predictors were assessed, including LDH, C-reactive protein, absolute lymphocyte counts, serum ferritin and NLr. Statistical analyses were undertaken using receiver-operator characteristics (rOC) curves, which were in turn compared using the method described by Hanley and McNeal. Results: One hundred and twelve patients were studied, most were male (60.7%) with a mean age of 63.4 ± 18.3 years. Twenty-two patients required IMV during their stay and 28 died. The NLr showed a good diagnostic accuracy in detecting patients that would require IMV (AUC 0.70, 95% CI 0.57-0.86) or died during the hospitalization (AUC 0.83, 95%CI 0.75-0.91). A cutoff point of 5.5 or higher had an 80.8% sensitivity and 73.1% specificity in detecting patients that died during their stay. Conclusions. NLr showed favorable diagnostic properties in detecting patients with COVID-19 at risk of adverse outcomes. Its wide availability and low cost are desirable features that might facilitate its implementation in routine clinical practice.