Neutrophil to lymphocyte ratio is associated with in-hospital mortality in older adults admitted to the emergency department.

Abstract

The objective of this study was to test the hypothesis that an elevated neutrophil to lymphocyte ratio (NLR) at admission is associated with and increased risk of mortality in older patients admitted to the emergency department (ED). We performed a retrospective analysis of patients admitted to the ED between November 2016 and February 2017. We included patients who were older than 65years who visited the ED with any medical problem. We excluded patients with hematologic malignancy. Baseline NLR values were measured at the time of admission to the ED. The primary outcome was all-cause in-hospital mortality. A multivariate logistic analysis was performed. A total of 2777 patients were included in this study. The median age was 75years (IQR 70-81), and 1359 (48.9%) patients were male. The in-hospital mortality rate was 5.0% (140 patients). The NLR value was higher in nonsurvivors (median, 8.08, IQR 4.29-15.25) than in survivors (median, 3.69, IQR 2.1-6.92, P<0.001). In the multivariate logistic regression analysis, the NLR was associated with all cause in-hospital mortality after adjusting for confounding factors (OR=1.03, 95% CI=1.014-1.046). These results show that the NLR at admission is associated with in-hospital mortality among patients older than 65years without hematologic malignancy. Thus, NLR at admission may represent a surrogate marker of disease severity.