The association between neutrophil-to-lymphocyte count ratio and mortality in septic patients: a retrospective analysis of the MIMIC-III database.

Abstract

BackgroundNeutrophil-to-lymphocyte count ratio (NLCR) has been shown as a feasible parameter associated with outcomes of tumor patients and an accessible predictor of bacteremia. However, only a handful of research shed the light on the association between NLCR and outcomes of septic patients. This study is aimed to evaluate the association between NLCR and all-cause mortality in a population of adult septic patients.MethodsWe extracted clinical data from Medical Information Mart for Intensive Care (MIMIC)-III V1.4, a free, large-scale, single-center database. NLCR was computed individually. Patients were categorized by quartiles of NLCR. The associations between NLCR quartiles and 28-day all-cause mortality in septic patients were assessed using Cox proportional hazards models and subgroup analyzes. To evaluate the accuracy of NLCR in predicting 28-day mortality of sepsis, receiver operator characteristic curves (ROC), areas under the curve (AUC), and the Youden’s J Index were calculated. Other outcomes included 7-day all-cause mortality, mortality in the intensive care units (ICU), in-hospital mortality and length of ICU stay.ResultsA total of 3,043 eligible patients were included in the study, of which, 760, 759, 766 and 758 patients were fallen in the first quartile (≤5.89), the second quartile (>5.89, ≤10.69), the third quartile (>10.69, ≤20.25) and the fourth quartile (>20.25) of NLCR, respectively. The 7-day mortality (13.4%, 9.9%, 13.6% and 14.2%; P=0.064) showed no difference in the four quartiles. In multivariate analysis, after adjusting for confounding factors, the highest NLCR quartile (>20.25) was associated with increased 28-day all-cause mortality [hazard ratio (HR) 1.22, 95% Cl: 1.01–1.49; P=0.046]. The areas under the receiver operating characteristic curves (AUROCs) for NLCR was 0.553 (95% CI: 0.529–0.576) for 28-day mortality.ConclusionsHigh NLCR (>20.25) is independently related to increased 28-day all-cause mortality in adult septic patients of a limited sensibility and specificity. Further large multi-center prospective studies are needed to confirm such relationship and to validate whose clinical significance.