Prognostic implications of neutrophil-lymphocyte ratio in COVID-19

The clinical presentation of COVID-19 ranges from a mild, self-limiting disease, to multiple organ failure and death. Most severe COVID-19 cases present low lymphocytes counts and high leukocytes counts, and accumulated evidence suggests that in a subgroup of patients presenting severe COVID-19, there may be a hyperinflammatory response driving a severe hypercytokinaemia which may be, at least in part, signalling the presence of an underlying endothelial dysfunction. In this context, available data suggest a prognostic role of neutrophil-lymphocyte ratio (NLR) in various inflammatory diseases and oncological processes. Following this rationale, we hypothesized that NLR, as a marker of endothelial dysfunction, may be useful in identifying patients with a poor prognosis in hospitalized COVID-19 cases.

A retrospective observational study performed at Hospital Universitario HM Puerta del Sur, Madrid, Spain, which included 119 patients with COVID-19 from 1 March to 31 March 2020. Patients were categorized according to WHO R&D Expert Group.

Forty-five (12.1%) patients experienced severe acute respiratory failure requiring respiratory support. Forty-seven (12.6%) patients died. Those with worse outcomes were older (P = .002) and presented significantly higher NLR at admission (P = .001), greater increase in Peak NLR (P < .001) and higher increasing speed of NLR (P = .003) compared with follow-up patients. In a multivariable logistic regression, age, cardiovascular disease and C-reactive protein at admission and Peak NLR were significantly associated with death.

NLR is an easily measurable, available, cost-effective and reliable parameter, which continuous monitoring could be useful for the diagnosis and treatment of COVID-19.