Usefulness of the measurement of plasma neutrophil gelatinase-associated lipocalin as a biomarker for predicting prognosis in hospitalized patients with pneumonia

Abstract

Background: While neutrophil gelatinase-associated lipocalin (NGAL) is known as an early marker of acute kidney injury, little is known about the roles of the measurement of NGAL in the management of acute lung diseases, such as pneumonia.

Aim: In this study, we investigated the role of plasma NGAL in predicting prognosis of hospitalized patients with pneumonia.

Method: With a prospective observation design, we enrolled adult patients, who were admitted to a university hospital for the treatment of pneumonia. At the time of admission, we measured plasma level of NGAL in addition to serum concentrations of C-reactive protein (CRP) and procalcitonin (PCT). Pneumonia Severity Index (PSI) was scored for the determination of the severity of pneumonia. Primary outcomes were PSI score at admission and mortality due to pneumonia after hospitalization.

Results: Concentrations of NGAL was much higher in non-survivors (n = 47) than survivors (n = 194) of pneumonia (679.2 vs. 308.5 ng/ml, P <0.001). In the analysis of survival, patients with high NGAL group showed a significantly higher survival rate than lower NGAL group (P = 0.009). NGAL was significantly correlated with PSI score (P <0.001), with 290.6 ng/ml in lowest PSI quartile and 373.9 ng/ml in highest PSI quartile. Receiver operating curve analysis showed that plasma NGAL is useful for predicting mortality (AUC 0.80, 95%CI 0.74-0.87, P <0.001).

Conclusions: These findings suggest that plasma NGAL is a useful biomarker for assessment of severity of pneumonia and predicting mortality in hospitalized patients with pneumonia.