Neutrophil-To-Lymphocyte Ratio: An Emerging Marker Predicting Prognosis in Elderly Adults with Community-Acquired Pneumonia

Abstract

Objectives: To explore the performance of the neutrophil-to-lymphocyte ratio (NLR), an index of systemic inflammation that predicts prognosis of several diseases, in a cohort of elderly adults with community-acquired pneumonia (CAP).

Design: Prospective clinical study from January 2014 to July 2016.

Setting: Unit of Internal Medicine, University of Catania, Catania, Italy.

Participants: Elderly adults admitted for CAP (N = 195).

Measurements: Clinical diagnosis of CAP was defined as the presence of a new infiltrate on plain chest radiography or chest computed tomography associated with one or more suggestive clinical features such as dyspnea, hypo- or hyperthermia, cough, sputum production, tachypnea (respiration rate >20 breaths per minute), altered breath sounds on physical examination, hypoxemia (partial pressure of oxygen <60 mmHg), leukocytosis (white blood cell count >10,000/μL). Clinical examination, traditional tests such as Pneumonia Severity Index (PSI); Confusion, Urea, Respiratory rate, Blood pressure, aged 65 and older (CURB-65), and NLR were evaluated at admission. The accuracy and predictive value for 30-day mortality of traditional scores and NLR were compared.

Results: NLR predicted 30-day mortality (P < .001) and performed better than PSI (P < .05), CURB-65, C-reactive protein, and white blood cell count (P < .001) to predict prognosis. No deaths occurred in participants with a NLR of less than 11.12. Thirty-day mortality was 30% in those with a NLR between 11.12% and 13.4% and 50% in those with a NLR between 13.4 and 28.3. All participants with a NLR greater than 28.3 died within 30 days.

Conclusions: These results would encourage early discharge of individuals with a NLR of less than 11.12, short-term in-hospital care for those with a NLR between 11.12 and 13.4, middle-term hospitalization for those with a NLR between 13.4 and 28.3, and admission to a respiratory intensive care unit for those with a NLR greater than 28.3.

Keywords: CAP; NLR; community-acquired pneumonia; elderly adults; prognostic score.