Evaluation of urinary L-FABP as an early marker for diabetic nephropathy in type 2 diabetic patients

BACKGROUND: Albuminuria is the standard biomarker for the diagnosis of diabetic nephropathy (DN). However, some patients with persistent microalbuminuria still progress to chronic kidney disease, raising the question of finding a better biomarker. This study aimed to evaluate the correlation of urinary liver-type fatty acid-binding protein (L-FABP) levels with renal function and to compare the role of urinary albumin-to-creatinine ratio (ACR) with urinary L-FABP in early detection of DN in type 2 diabetic patients. METHODS: The cross-sectional study was done on 106 type 2 diabetic patients and 30 non-diabetic people. L-FABP was measured with the Latex enhanced immunoturbidimetric technique. RESULTS: There was a strong and negative correlation between the urine L-FABP levels and eGFR (r = -0.606, p<0.001). The urinary L-FABP levels were significantly higher (p<0.001) in the normoalbuminuria diabetic group than the non-diabetic control group. The ROC-curve analyses in the diabetic patients and the normoalbuminuria diabetic patients showed that the AUCL-FABP was remarkably higher (p<0.001) than the AUCACR. An optimal cutoff value of 5 mg L-FABP/g Cr (with the sensitivity of 98.1% and specificity of 90%) and of 4.3 mg L-FABP/g Cr (with the sensitivity of 100% and specificity of 86.67%) was set to detect DN in the diabetic patients and the normoalbuminuria diabetic patients, respectively. CONCLUSIONS: The change in urinary L-FABP levels happened earlier than in urinary albumin during renal function impairment. Urinary L-FABP can be used as a better indicator than ACR for early detection of DN in type 2 diabetes.