Plasma Fatty Acid-Binding Protein 4 Increases with Renal Dysfunction in Type 2 Diabetic Patients without Microalbuminuria

Background: Fatty acid–binding protein 4 (FABP4) has been linked to metabolic syndrome development, diabetes, and arteriosclerosis, but the role of FABP4 in target organ damage has not been assessed. We evaluated whether plasma FABP4 is associated with renal dysfunction in type 2 diabetic patients. Methods: In 263 individuals (161 type 2 diabetic patients and 102 healthy nondiabetic controls), we analyzed the correlation between FABP4 and creatinine or glomerular filtration index (MDRD-GFR) regarding the presence or absence of microalbuminuria. Patients with severe chronic kidney disease (MDRD-GFR <30 mL/min/1.73 m2) or albuminuria were not included. Results: FABP4 concentrations were higher in diabetic patients with MDRD-GFR <60 mL/min/1.73 m2 ( P <0.001). We observed a significant, direct correlation between FABP4 and creatinine ( r = 0.446, P <0.001) and an inverse correlation between FABP4 and MDRD-GFR ( r = −0.511, P <0.001) in type 2 diabetic patients, but not in nondiabetic individuals. These correlations were sustained when only those patients without microalbuminuria were analyzed ( r = 0.414, P <0.001 and r = −0.510, P <0.001, respectively). Type 2 diabetic patients with FABP4 in the highest tertile compared with those in the lower tertiles had increased adjusted odds ratios for moderate renal dysfunction [7.5 (95%CI 1.8–30.7), P = 0.005 and 15.3 (3.1–76.4), P = 0.001; respectively], independent of microalbuminuria. Conclusions: High FABP4 plasma concentrations are associated with high plasma creatinine and low MDRD-GFR in patients with type 2 diabetes even in the absence of microalbuminuria or clinically relevant alterations of creatinine and MDRD-GFR values. FABP4 concentrations should be taken into consideration as an early marker of kidney damage in patients with type 2 diabetes.