BACKGROUND: Hemorheologic alterations or changes in blood viscosity have been suggested to play a role in the pathogenesis of microvascular complications in diabetes. We measured various hemorheologic parameters in type 2 diabetes patients at different stages of chronic kidney disease (CKD) and assessed their possible role as early markers of diabetic nephropathy and renal insufficiency.
SUBJECTS AND METHODS: One hundred-five patients with type 2 diabetes were divided into four groups according to glomerular filtration rate (GFR), which represents the kidney function. Hemorheologic parameters, including erythrocyte deformability, fibrinogen/elongation index (EI), and aggregation index (AI) were measured using a microfluidic hemorheometer, and critical shear stress (CSS) was measured using a microfluidic technique. Various metabolic parameters were assessed from fasting blood samples, and the urine albumin-to-creatinine ratio (ACR) was calculated from first morning voided urine.
RESULTS: There were significant differences in red blood cell (RBC) deformability, AI, CSS, fibrinogen/EI, and ACR among patients in different stages of CKD (all P<0.05). RBC deformability and fibrinogen/EI significantly differed between normal (GFR >90 mL/min/1.73 m(2)) and CKD stage 2 (GFR 60-90 mL/min/1.73 m(2)) patients, whereas there was no such difference in ACR. In multiple regression analysis, fibrinogen/EI under a moderate shear stress of 3 Pa was an independent predictor of GFR (β=-0.328, P<0.05). Also, AI, CSS, and fibrinogen/EI were significantly different among patients at different stages of diabetic nephropathy, with a significant difference in fibrinogen/EI between normal and microalbuminuric patients (all P<0.05).
CONCLUSIONS: RBC deformability and fibrinogen/EI are sensitive parameters measured via point-of-care testing for detecting erythrocyte alterations in early CKD and nephropathy in patients with type 2 diabetes. Further studies are warranted to verify their use as screening tools for diabetic nephropathy and renal impairment.