NEUTROPHILS, LYMPHOCYTES AND THEIR RATIO AS PREDICTORS OF OUTCOMES IN PATIENTS WITH COVID-19

Abstract

Background. There have been practically no reports that describe, in early stages of COVID-19, simple methods to predict the outcome of this insidious disease. At the same time, predictors of favorable or fatal COVID-19 outcome are important, since they would allow clinicians to adjust treatment in a timely manner. Aim. To develop simple and affordable predictors that are highly likely to forecast outcome at early stages of COVID-19. Methods. The study was conducted in 125 patients with COVID-19, in whom the number of leukocytes, neutrophils, lymphocytes, and the neutrophil/lymphocyte ratio (NEU/LYM) were determined on days 1, 5, 7, 10, 14, and 21 of hospitalization. To calculate predictive threshold values of survival and mortality, ROC analyses were performed. To assess the significance of changes in the areas under the ROC curves (AUC) in the illness dynamics, the ROC curves were compared in pairs (1-5, 5-7, 7-10, 10-14, 14-21 days) using the DeLong nonparametric algorithm. Results. There were significant differences between the number of leukocytes, neutrophils, lymphocytes, and the NEU/LYM ratio in patients with a favorable outcome and those that later died. The most significant outcome predictors were the number of neutrophils and, especially, the NEU/LYM index, with an increase in which, the likelihood of death sharply increased. The ROC-analysis showed that on day 1, the outcome predictive ability of AUC for the NEU/LYM ratio was 79%; by day 5, it increased to 84%; from day 10 to day 21, it exceeded 90 %. In the presence of high indicators for potentially lethal outcomes, it is necessary to administer immunomodulators. For this purpose, we recommend using a complex of polypeptides from the thymus gland, i.e., thymalin, which has proven beneficial for treatment of patients with moderate to severe COVID-19. Conclusion. The neutrophil/lymphocyte ratio predicts of the outcome of severe COVID-19 with high sensitivity and specificity.