Glycaemic control influences peripheral blood flow and haemorheological variables in patients with diabetes mellitus

Since persistent uncontrolled hyperglycaemia predisposes to vascular complications in diabetics, this study aimed at assessing the relationship of glycaemic control to plasma fibrinogen concentration, relative plasma viscosity and ankle arterial blood flow in diabetic patients with (N=28) and without neuropathy (N=34) compared with non-diabetic controls (N=21). Glycaemic control was determined by total glycated haemoglobin (GHb) levels. Patients were placed into three categories of glycaemic control, namely good (GHb 4-< 8%), fair (GHb 8-12%) and poor (GHb > 12%). Compared with non-diabetics, blood flow was significantly higher (p < 0.05) in patients with good but not poor glycaemic control. Fibrinogen was significantly higher in patients with fair and poor glycaemic control than in non-diabetic subjects (p < 0.05). In non-neuropathic patients, viscosity was higher (p < 0.05) in those with fair control and significantly different (p < 0.05) between those with fair and poor control. The results suggest that the initial vasodilatation in the periphery is attenuated by poor glycaemic control, contributing to the decrease in ankle arterial blood flow as a consequence of the simultaneous increase in plasma fibrinogen and viscosity. These adverse changes may contribute to the development of the diabetic foot.