Increased low shear rate erythrocyte viscosity in insulin dependent diabetes mellitus

Different methodologies and heterogeneous patient groups have led to conflicting results with respect to erythrocyte deformability in diabetes mellitus. Therefore we studied erythrocyte deformability by means of viscosity measurements in insulin dependent diabetics without major vascular complications and its relationship with metabolic control. Viscosity measurements of red cells suspended in a non-aggregating physiological medium were performed with a Contraves Low Shear 30 viscosimeter at low (0.945s −1 ) and high (128.5s −1 ) shear rate. Erythrocyte viscosity in the diabetic group was normal at high shear rate but significantly increased at low shear rate. This increased low shear rate viscosity was observed only in patients with bad metabolic control. Two important conclusions can be derived from our results: detecting abnormal erythrocyte rheology in diabetes depends upon experimental conditions and in insulin dependent diabetics without vascular complications erythrocyte flow properties depend on the metabolic status.