Urinary liver-type fatty acid-binding protein predicts recovery from acute kidney injury.

Objectives: Despite significant advances in the epidemiology of acute kidney injury (AKI), there is no reliable method to predict renal recovery. Using acute kidney injury network (AKIN) criteria, we tested whether higher urinary L-FABP (uL-FABP) concentrations in the patients with AKIN stage 3 (AKIN3) after nephrology consultation would predict failure to recover.

Methods: This is a prospective cohort study of 114 patients with AKIN3 at WuXi People's Hospital from August 2011 to July 2014. The levels of serum creatinine, urine creatinine, and uL-FABP were obtained at the time of nephrology consultation.

Results: Patients who recovered had lower uL-FABP than those who failed to recover at time of nephrology consultation (71.42 (11.1 - 118.3) vs. 335.18 (103.9 - 422.3) ng/mg × creatinine, p < 0.001). Urinary L-FABP predicted failure to recover with an area under the receiver operating characteristic curve of 0.906 (95% CI 0.837 - 0.953). A clinical model using age, APACHE II score and acute tubular necrosis severity scoring index (ATN-ISS) predicted failure to recover with an area under the curve of 0.825 (95% CI 0.743 - 0.890). When uL-FABP was compared to the clinical model, the reclassification of risk of renal recovery had significantly improved by 35.1%.

Conclusion: Urinary L-FABP appears to be a useful biomarker to predict failure to recover during hospitalization in the cohort of patients with AKIN3.