Novel urinary biomarkers to differentiate AKI etiologies and predict mortality in decompensated cirrhosis patients: a prospective cohort study.

INTRODUCTION: The differentiation of causes of Acute Kidney Injury (AKI) in decompensated chronic liver disease (DCLD) presents a diagnostic challenge. This study aims to evaluate the diagnostic and prognostic utility of Neutrophil gelatinase-associated lipocalin (NGAL), Kidney injury molecule-1 (KIM-1), and interleukin-18 (IL-18) in cirrhotic patients with AKI. METHODS: This prospective cohort study was conducted at a tertiary care hospital in northeast India. Patients (n = 100) were divided into cases comprising decompensated cirrhosis with AKI (n = 50) and controls comprising decompensated cirrhosis without AKI (n = 50). Cases included patients with acute tubular necrosis (ATN) (n = 10), hepatorenal syndrome (HRS) (n = 18), and prerenal azotemia (PRA) (n = 22). Urinary NGAL, IL-18 and KIM-1 were analyzed statistically to distinguish the causes of AKI and predict 90-day mortality. RESULTS: NGAL [cutoff: 339.6 pg/mL, sensitivity: 80%, specificity: 83.3%, Area Under the Receiver Operating Characteristic Curve (AUROC): 0.867] and IL-18 (cutoff: 67.75 pg/mL, sensitivity: 70%, specificity: 88.9%, AUROC: 0.839) differentiated ATN from HRS. NGAL (cutoff: 358.15 pg/mL, AUROC: 0.878) and IL-18 (67.75 pg/mL, AUROC: 0.885) distinguished ATN from non-ATN cases. IL-18 (cutoff: 30.95 pg/mL, AUROC: 0.732) effectively differentiated HRS from PRA cases. KIM-1 had a modest diagnostic performance comparable to serum creatinine. NGAL significantly predicted 90-day mortality (Adjusted Odds Ratio: 1.024; p = 0.014). CONCLUSION: Both IL-18 and NGAL can assist clinicians in differentiating the causes of AKI while improving the prognostic ability of existing scores in DCLD patients.