Urinary Neutrophil Gelatinase-Associated Lipocalin as a Predictor of COVID-19 Mortality in Hospitalized Patients

Neutrophil gelatinase-associated lipocalin (NGAL) is a protein secreted by activated neutrophils and certain tissues. The aim of this study was to investigate the prognostic role of urinary neutrophil gelatinase-associated lipocalin (uNGAL) in hospitalized COVID-19 patients with regard to mortality. The prospective observational cohort study involved 86 hospitalized adult COVID-19 patients. Patients’ urine samples were collected upon admission and 48–72 h after admission. General anamnesis and clinical status information were obtained from medical records. Within 24 h of sample collection, urine aliquots were centrifuged, the supernatant was separated, and samples were frozen at −80 °C until uNGAL concentration measurement, which was performed within two years of sample collection. The patients were categorized into groups based on disease outcome (survived/deceased). Data analysis was performed to identify predictive factors and diagnostic indicators for the unfavorable outcome group using logistic regression and ROC curve methods. Logistic regression associated age, cardiomyopathy, invasive mechanical ventilation, and uNGAL concentration (follow-up sampling) with mortality. ROC analysis identified uNGAL concentration (follow-up sampling) as an indicator of mortality, with a cut-off value of >23.8 ng/mL. This study concludes that there is an association between disease outcome and uNGAL concentration in COVID-19 patients. However, understanding the dynamics of uNGAL concentration during COVID-19 remains limited, which is crucial for its effective clinical application.