Neutrophil‐to‐lymphocyte ratio and lymphocyte‐to‐C‐reactive protein ratio in patients with severe coronavirus disease 2019 (COVID‐19): A meta‐analysis

Abstract

To the Editor, Since March 11, 2020, the World Health Organization defined coronavirus disease 2019 (COVID‐19) as a pandemic, with a series of confirmed cases that currently exceeded 300,000 people worldwide and with approximately 14,500 deaths. Accumulated evidence suggests that a subgroup of patients with severe COVID‐19 could have a dysregulation of the immune response that allows the development of viral hyperinflammation. Thus, all patients with severe COVID‐19 should be screened for hyperinflammation using laboratory parameters to improve mortality. Neutrophil‐to‐lymphocyte ratio (NLR) and lymphocyte‐to‐C‐reactive protein ratio (LCR) are established inflammation markers that reflect systemic inflammatory response, and both are available in almost all laboratories. In this study, a meta‐analysis was performed to investigate whether NLR and LCR values can help predict clinical severity in patients with COVID‐19. First, we conducted an electronic search in different search engines that included Medline (PubMed interface), Scopus, Web of Science via Raven and Google Scholar, using the keywords “Severe 2019‐nCoV” OR "Severe COVID‐19" without date (i.e. until March 23, 2020) or language restrictions. The title, abstract, and full text of all the articles identified according to these search criteria were analyzed, considering for our meta‐analysis only those that reported data in COVID‐19 patients with or without severe disease (defined as severe or with the need to enter the intensive care unit or the use of mechanical ventilation).