Prognostic implications of neutrophil‐lymphocyte ratio in COVID‐19

Background 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. Design 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. Results 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