Abstract: Objective To explore the clinical value of urinary N-Acetyl-β-D-glucosaminidase (uNAG) associated with serum creatinine (sCr) in predicting acute kidney injury (AKI) in adult critically ill patients. Methods In this prospective study, we enrolled 124 adult critically ill patients who admitted to the mixed ICU of Xiaolan Hospital of Southern Medical University during September 2015 to January 2016. According to the Kidney Disease Improving Global Outcomes (KDIGO) criterion, the patients were divided into non- AKI group and AKI group (including mild AKI and severe AKI)． The receiver operating characteristic (ROC) curve and the area under curve (AUC) were used to evaluate the capabilities of the biomarkers in predicting AKI. Results Of the 124 patients, 34 patients (27.4%) developed AKI. The levels of uNAG and sCr were significantly higher in AKI group than in non-AKI group (P＜0.001)．In this cohort, 15 patients (12.1%) developed severe AKI. The levels of uNAG and sCr were significantly higher in severe AKI patients than in non- AKI and mild AKI patients (P＜0.05). The AUC value was higher in combined uNAG and sCr (0.933 & 0.946) than uNAG or sCr alone in predicting AKI and severe AKI. In-hospital mortality was 9.7% and renal replacement therapy rate was 4.0%. AKI group had higher renal replacement therapy rate and longer ICU stay than non AKI group (P＜0.05). Conclusions uNAG is a sensitive biomarker for predicting AKI in adult critically ill patients. When uNAG combined with sCr, AKI prediction can be further improved.

Key words: Critical patient, N-Acetyl-β-D-glucosaminidase, Acute kidney injury, Diagnosis