Urinary neutrophil gelatinase-associated lipocalin predicts mortality and identifies acute kidney injury in cirrhosis.

Background: Kidney failure predicts mortality in patients with cirrhosis. Identification of kidney failure etiology and recognition of those at the highest mortality risk remains a challenge.
Aims: We hypothesized that urinary neutrophil gelatinase-associated lipocalin (uNGAL) predicts mortality and identifies hepatorenal syndrome (HRS) in patients with cirrhosis.
Methods: Prospectively enrolled patients with cirrhosis were investigated by uNGAL immunoblot upon hospital admission. Kidney failure type was determined blinded to NGAL measurements.
Results: One hundred eighteen patients were enrolled. Fifty-two (44 %) patients had normal kidney function, 14 (12 %) stable chronic kidney disease, 17 (14 %) prerenal azotemia, 20 (17 %) HRS, and 15 (13 %) intrinsic acute kidney injury (iAKI). Patients with HRS had uNGAL levels intermediate between prerenal azotemia [median (IQR) 105 (27.5-387.5) vs. 20 (15-45) ng/mL, p = 0.004] and iAKI [325 (100-700), p < 0.001]. Fifteen (13 %) patients died. In unadjusted analysis, uNGAL predicted inpatient mortality (OR 2.00, 95 % CI 1.36-2.94) and mortality or liver transplantation (OR 2.01, 95 % CI 1.42-2.85). In multiple regression models, uNGAL > 110 ng/mL (OR 6.05, 95 % CI 1.35-27.2) and HRS (OR 6.71, 95 % CI 1.76-25.5) independently predicted mortality, adjusting for age and serum creatinine >1.5 mg/dL.
Conclusions: uNGAL strongly predicts short-term inpatient mortality in both unadjusted and adjusted models. Patients with HRS may have uNGAL levels intermediate between those with prerenal azotemia and iAKI. Further studies are needed to determine if uNGAL can improve discrimination of HRS from other types of acute kidney injury and predict short- and long-term cirrhosis outcomes.