[Neutrophil to lymphocyte ratio as a prognostic marker in COVID-19]

In December 2019, a new coronavirus was identified as the cause of an outbreak of pneumonia and respiratory distress in Wuhan, China. It was declared pandemic in March 2020. It is important to know predictors of poor outcomes in order to optimize the strategies of care in newly diagnosed patients. The neutrophil to lymphocyte ratio (NLR) constitutes a novel prognostic marker for oncologic, cardiovascular and infectious diseases. We aimed to assess its prognostic value in COVID-19. We evaluated a retrospective cohort of 131 patients with COVID-19 from March to May 2020. We analyzed the association of an NLR = 3 with severe COVID-19, baseline characteristics of the population and the mortality rate. The median age was 52 years, and 54% were men. 21 patients presented criteria of severe disease, 9 of them required mechanical ventilation. NLR = 3 was found in 81% (18/21) of severe patients and in 33% (36/110) of mild patients (OR = 8.74. 95% CI 2.74-27.86; p < 0.001). Age and hypertension were associated with severe disease. A mortality rate of 7% (9) was obtained. Seven of the 9 patients who died presented NLR = 3, with a significant association between mortality and NLR = 3 (p = 0.03). NLR could be used in conjunction with other predictors, as an early prognostic marker in COVID-19 given its accessibility and low cost.