Neutrophil-to-lymphocyte ratio as a prognostic marker in critically-ill septic patients

Abstract

Background: We evaluated the associations between the neutrophil-to-lymphocyte ratio (NLR) or changes in NLR and outcomes in septic patients.

Methods: Patients who met the criteria for severe sepsis or septic shock were categorized into five groups according to the quintile of initial NLR value. We defined two risk groups according to NLR value and changes in NLR during the first two days (defined as the persistently low NLR group and the persistently high NLR group). The primary outcome was 28-day mortality.

Results: A total of 1395 patients were included. The median initial NLR values from Quintile 1 to Quintile 5 were as follows: 0.2 (IQR [interquartile range], 0.1-0.7), 3.4 (IQR, 2.6-4.7), 8.6 (IQR, 7.1-9.9), 15.4 (IQR, 13.3-17.8), and 31.0 (IQR, 24.6-46.8), respectively. The 28-day mortality values for the same groups were as follows: 24.4%, 12.2%, 11.1%, 11.8%, and 16.1% (P<.01). Cox regression analysis showed that inclusion in Quintile 1 or Quintile 5 was a significant risk factor predicting 28-day mortality compared to Quintile 3 (adjusted hazard ratio [HR]: 1.79 (95% confidence interval [CI], 1.15-2.78) in Quintile 1; 1.67 (95% CI, 1.04-2.66) in Quintile 5). The analysis indicated that persistently low NLR (adjusted HR: 2.25, 95% CI, 1.63-3.11) and persistently high NLR (adjusted HR: 2.65, 95% CI, 1.64-4.29) were significant risk factors.

Conclusions: In summary, the initial NLR measured at ED admission was independently associated with 28-day mortality in patients with severe sepsis and septic shock. In addition, change in NLR may prove to be a valuable prognostic marker.

Keywords: Lymphocytes; Neutrophils; Prognosis; Sepsis; Shock.