Prognostic Significance of Neutrophil-to-Lymphocyte Ratio in Patients with Sepsis: A Prospective Observational Study

BACKGROUND The neutrophil-to-lymphocyte ratio (NLR) is an easily accessible biological marker that has been reported to represent disease severity. The aim of this study is to investigate the association between NLR and mortality in patients with sepsis. METHODS A total of 333 consecutive adult patients with sepsis were screened for eligibility in this prospective, observational study cohort. Severity scores and leukocyte counts were prospectively recorded upon entry to the intensive care unit (ICU). Receiver operating characteristic (ROC) curves and binary logistic regression models were used to assess the performance of NLR in predicting unfavorable outcome. Correlations between variables and disease severity were analyzed through Spearman correlation tests. RESULTS Median NLR levels were significantly higher in patients who died than in survivors. NLR had a modest power for predicting poor outcome as suggested by area under the curve (AUC) of 0.695 ± 0.036. Multivariate linear regression indicated that increased NLR levels were related to unfavorable outcome independently of the effect of possible confounders. Spearman correlation tests showed that there was a positive correlation between NLR levels and disease severity. CONCLUSIONS Increased NLR levels were independently associated with unfavorable clinical prognosis in patients with sepsis. Further investigation is required to increase understanding of the pathophysiology of this relationship.