Performance of Urinary Liver-Type Fatty Acid-Binding Protein in Acute Kidney Injury: A Meta-analysis

Background: Urinary liver-type fatty acid-binding protein (L-FABP) is a proximal tubular injury candidate biomarker for early detection of acute kidney injury (AKI), with variable performance characteristics depending on clinical settings. Study Design: Meta-analysis of diagnostic test studies assessing the performance of urinary L-FABP in AKI. Setting & Population: Literature search in MEDLINE, EMBASE, Scopus, Google Scholar, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov using search terms liver-type fatty acid-binding protein and L-FABP. Selection Criteria for Studies: Studies of humans investigating the performance characteristics of urinary L-FABP for the early diagnosis of AKI and AKI-related outcomes, including dialysis requirement and mortality. Predictor: Urinary L-FABP. Outcomes: Diagnosis of AKI, dialysis requirement, and in-hospital death. Results: 15 prospective cohort and 2 case-control studies were identified. Only 7 cohort studies could be meta-analyzed. The estimated sensitivity of urinary L-FABP level for the diagnosis of AKI was 74.5% (95% CI, 60.4%-84.8%), and specificity was 77.6% (95% CI, 61.5%-88.2%). The estimated sensitivity of urinary L-FABP level for predicting dialysis requirement was 69.1% (95% CI, 34.6%-90.5%), and specificity was 42.7% (95% CI, 3.1%-94.5%); for in-hospital mortality, sensitivity and specificity were 93.2% (95% CI, 66.2%-99.0%) and 78.8% (95% CI, 27.0%-97.4%), respectively. Limitations: Paucity and low quality of studies, different clinical settings, and variable definitions of AKI. Conclusions: Although urinary L-FABP may be a promising biomarker for early detection of AKI and prediction of dialysis requirement and in-hospital mortality, its potential value needs to be validated in large studies and across a broader spectrum of clinical settings. Am J Kidney Dis. 61(3):430-439. (C) 2013 by the National Kidney Foundation, Inc.