Clinical significance of urinary liver-type fatty acid-binding protein as a predictor of ESRD and CVD in patients with CKD

To improve outcomes in patients with chronic kidney disease (CKD), it is important to identify prognostic factors for end-stage renal disease (ESRD) as well as cardiovascular disease (CVD). This study assessed urinary concentrations of albumin, N-acetyl-beta-D-glucosaminidase (NAG), and liver-type fatty acid-binding protein (L-FABP), as predictors of ESRD and CVD. A prospective, observational, multicenter study, comprising 244 Japanese outpatients with CKD who had a follow-up period of at least 3 months. The primary endpoint was the first onset of a nonfatal or fatal CVD event and progression to ESRD, defined as myocardial infarction, stroke, or artery revascularization (coronary, carotid or peripheral), and initiation of dialysis. During a median follow-up of 3.8 years, the primary endpoint occurred in 39 (15.8 %) patients. Irrespective of diabetes, high urinary L-FABP correlated with the development of ESRD and CVD. The areas under the receiver-operator characteristic curves (AUCs) for predicting the primary endpoint for urinary concentrations of L-FABP, albumin, and NAG were 0.825, 0.797, and 0.722, respectively. Cox regression analyses, which were adjusted for factors known to influence the primary endpoint, including patient characteristics, and serum and urinary parameters, demonstrated that the primary outcome was associated with high urinary L-FABP and low eGFR [p = 0.049, hazard ratio = 1.341 (95 % CI 1.005-1.790); and p < 0.000, hazard ratio = 0.953 (95 % CI 0.930-0.976), respectively]. Urinary L-FABP may be a useful prognostic marker of progression to ESRD and the onset of CVD in patients with CKD.