Neutrophil-to-lymphocyte Ratio Relation to Sepsis Severity Scores and Inflammatory Biomarkers in Patients with Community-acquired Pneumonia: A Case Series

Abstract

Background and objectives: Neutrophil to lymphocyte ratio (NLR) as calculated from the white cell differential blood count is considered a promising marker for the prognosis of patients with various diseases, including sepsis. This study was designed to assess the possible use of neutrophil-to-lymphocyte ratio in the prediction of survival outcomes in patients with community acquired pneumonia (CAP). A secondary objective was to compare the prognostic accuracy of NLR with the commonly used severity scores of sepsis SOFA, APACHE II and SAPS II.

Methods: This was a retrospective study based on data extracted from 26 patients suffering from acute CAP. The study period was from February 01, 2017 until April 30, 2017. All patients with CAP were presented in the Emergency Department (ED) of the University Hospital of Patras, Greece and were treated after admission in the Internal Medicine Department. The neutrophil-to-lymphocyte ratio (NLR) was calculated from the white blood cell count (WBC) values measured from a peripheral venous blood specimen drawn on admission. It was then compared with C-reactive protein (CRP) serum levels and the sepsis calculated prognostic scores APACHE II, SAPS II and SOFA. The impact of the above parameters was evaluated in relation to the final outcome.

Results: The mean period of hospitalization for the enrolled patients was 9.3 days (SD 5.8 days). Twenty-four patients (92.3%) got finally discharged from the hospital and two (7.7%) died during the hospitalization. Mean NLR and serum CRP values on admission were 10.2 ± 8.8 (min 1.4; max 34.7) and 11.4 ± 11 mg/dL (min 0.4; max 42.6) respectively. Based on the correlation analysis, serum CRP was more strongly positively correlated with NLR (r = 0.543, P = 0.004), than total WBC (r = 0.454, P = 0.02). None of the biomarkers of inflammation measured or computed in the study (CRP, WBC, NLR) showed any correlation with either the days of hospitalization or the sepsis prognostic scores.

Conclusions: NLR shows a statistical significant correlation to the commonly used inflammatory markers CRP and total WBC in the small sample size of patients with CAP that we assessed. Although NLR is a simple, cheap and rapidly available measurement in the ED, future, larger prospective studies are warranted to confirm its possible value as a prognostic index in sepsis patients with CAP.

Keywords: APACHE II; SOFA; community acquired pneumonia (CAP); neutrocyte-to-lymphocyte ratio (NLR); sepsis.