Association between the Neutrophil-to-Lymphocyte Ratio and Inpatient Mortality in Hospitalized Older Veterans with COVID-19 Infection

Objectives: Determine the association of high neutrophil-to-lymphocyte ratio (NLR) values with inpatient mortality and other outcomes in older veterans hospitalized with coronavirus disease 2019 (COVID-19).Methods: This was a retrospective, multicenter, cohort study of hospitalized adults, with laboratory-confirmed COVID-19 infection who were studied for 1 year after discharge or until death. The NLR was categorized into tertiles, and we determined frailty status with the 31-item Veterans Affairs Frailty Index. Multivariate logistic regression and adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were performed to assess the association between NLR and clinical outcomes.Results: The study included 615 hospitalized adult veterans, mean age 66.12 (standard deviation 14.79) years, 93.82% (n = 577) male, 57.56% (n = 354) White, 81.0% (n = 498) non-Hispanic, median body mass index of 30.70 (interquartile range 25.64-34.99, standard deviation 7.13), and median length of stay of 8 days (interquartile range 3-15). Individuals in the middle and upper tertile groups had higher inpatient mortality (8.37%, n = 17 and 18.36%, n = 38, respectively) as compared with the lower tertile (2.93%, n = 6, P < 0.001). Compared with the lowest tertile, the middle and upper tertiles had a higher risk of inpatient mortality (aOR 3.75, 95% CI 1.38-10.21, P = 0.01, and aOR 8.13, 95% CI 3.18-20.84, P < 0.001, respectively). The highest tertile had a higher odds of intensive care unit admission (aOR 4.47, 95% CI 2.33-8.58, P < 0.001) and intensive care unit transfer (aOR 3.54, 95% CI 1.84-6.81, P < 0.001).Conclusions: The NLR score is a clinically useful tool to predict in-hospital mortality in older patients with COVID-19.