The role of urinary liver-type fatty acid-binding protein in critically ill patients

Abstract

Although several urinary biomarkers have been validated as early diagnostic markers of acute kidney injury (AKI), their usefulness as outcome predictors is not well established. This study aimed to determine the diagnostic and prognostic abilities of urinary liver-type fatty acid-binding protein (L-FABP) in heterogeneous critically ill patients. We prospectively collected data on patients admitted to medical and surgical intensive care units (ICUs) from July 2010 to June 2011. Urine neutrophil gelatinase-associated lipocalin (NGAL) and L-FABP at the time of ICU admission were quantitated. Of the 145 patients, 54 (37.2%) had AKI defined by the Acute Kidney Injury Network (AKIN) criteria. AKI patients showed significantly higher level of urinary NGAL and L-FABP and also higher mortality than non-AKI patients. The diagnostic performances, assessed by the area under the ROC curve, were 0.773 for NGAL and 0.780 for L-FABP, demonstrating their usefulness in diagnosing AKI. In multivariate Cox analysis, urinary L-FABP was an independent predictor for 90-day mortality. Urinary L-FABP seems to be promising both for the diagnosis of AKI and for the prediction of prognosis in heterogeneous ICU patients. It needs to be further validated for clinical utility.

Keywords: Acute Kidney Injury; Liver-Type Fatty Acid-Binding Protein; Neutrophil Gelatinase-Associated Lipocalin; Prognosis.

Fig. 1

Diagnostic performance for AKI. Receiver operating characteristic curves for the diagnosis of AKI. The area under the ROC curves and the cutoff value of each urinary biomarker are presented in the separate table under the figure.

Fig. 2

Predictive performance for 90 day mortality. Receiver operating characteristic curves of SAPS II score and urinary L-FABP for 90 day mortality. The AUC-ROCs are presented in Table 2.

Fig. 3

Kaplan-Meier survival curves according to the level of urinary L-FABP. Log-Rank test.