Early expression of urinary neutrophil gelatinase-associated lipocalin biomarker predicts acute kidney injury complicating circulatory shock

Abstract

Background: The novel urinary neutrophil gelatinase-associated lipocalin (uNGAL) is an early and highly predictive biomarker that is rapidly released in acute kidney injury (AKI). Objective: We investigated the early expression of uNGAL (first 4 days after injury) as a predictor of acute kidney injury complicating circulatory shock. Methods: Urinary-NGAL level was measured in collected urine samples of 45 patients (pts) with circulatory shock, during the first 6 h and after 24 h of onset of shock. Eleven patients responded to fluid infusion ± vasopressors and were considered as a control group. Results: The estimated uNGAL at day 1 and day 2, could predict AKI presenting at days 2, 3 and 4 (P < 0.05, <0.001 and <0.001, <0.001), respectively. Apart from all conventional kidney parameters and biomarkers, significant inverse correlations could be detected only between uNGAL at days 1 and 2 with the corresponding urine output in the patients’ group (r = −0.41 and −0.64, P < 0.05 and <0.001, respectively). The best cutoff value of uNGAL at day 1 was 26 ng/mL, with sensitivity and specificity of (62% and 69%) and (75% and 80%), for prediction of AKI presented at days 2 and 3, respectively. While the best cutoff at day 2 was 29 ng/mL, with sensitivity and specificity of (70% and 74%) and (90% and 80%) for prediction of AKI diagnosed at days 3 and 4, respectively. Urinary-NGAL at days 1 and 2 could significantly predict mortality complicating AKI only at day 2 (area under curves were 0.65 and 0.86, and P < 0.05 and <0.001, respectively). Conclusions: Urinary-NGAL seems to be a potential early and sensitive biomarker for AKI complicating circulatory shock. Its persistent increased level at day 2 also can predict mortality complicating AKI in those patients.

Keywords

• Urinary-NGAL
• Acute kidney injury
• Circulatory shock