Comparative Diagnostic Performance of Urinary Neutrophil Gelatinase–Associated Lipocalin and Renal Resistive Index in Patients of Decompensated Cirrhosis with Acute Kidney Injury.

Abstract

Background: Acute kidney injury (AKI) in decompensated cirrhosis carries high mortality, with prognosis varying by etiology. Accurate differentiation between acute tubular necrosis (ATN) and other AKI causes remains challenging using conventional markers.

Objective: To compare the diagnostic accuracy of urine neutrophil gelatinase-associated lipocalin (uNGAL) versus renal resistive index (RRI) for differentiating ATN from other AKI causes in decompensated cirrhosis patients.

Methods: This prospective observational comparative study study enrolled 75 patients with decompensated cirrhosis and AKI stage ≥1B at a tertiary care hospital. uNGAL and RRI were measured at diagnosis (Day 0) and 48 hours after volume expansion (Day 2). Final AKI phenotype was determined using established clinical criteria. Diagnostic performance was evaluated using receiver operating characteristic curves.

Results: The cohort included 30 HRS (40.0%), 23 ATN (30.7%), and 22 prerenal AKI patients (29.3%). ATN patients demonstrated significantly higher median NGAL levels (218 µg/g creatinine) versus HRS (105 µg/g) and prerenal AKI (42 µg/g), p<0.001. NGAL showed superior diagnostic accuracy (AUROC 0.97) compared to RRI (AUROC 0.92), p=0.042. At >180 µg/g creatinine cutoff, NGAL achieved 91.3% sensitivity and 96.2% specificity. All prerenal AKI patients responded to volume expansion versus none with ATN. ATN had highest mortality (43.5%) and RRT requirement (43.5%).

Conclusion: Urine NGAL is superior to RRI for diagnosing ATN in decompensated cirrhosis with AKI, demonstrating excellent diagnostic accuracy. Implementation of uNGAL testing could improve clinical decision-making and patient outcomes in this high-risk population.