Glycaemia, arterial pressure and micro-albuminuria in Type 1 (insulin-dependent) diabetes mellitus

Abstract

Plasma glucose control and arterial pressure were assessed in 28 Type 1 (insulin-dependent) diabetic patients with different degrees of micro-albuminuria. They were divided into two groups according to their urinary albumin excretion rate: a low micro-albuminuria group (n= 16) with albumin excretion ranging between 12.1 and 28.9 μg/min and a high micro-albuminuria group (n= 12) with albumin excretion between 32.4 and 91.3 μg/min. The groups were matched for age, sex and duration of diabetes with the same number of normo-albuminuric (2.0–10.4 μg/min) diabetic control subjects. Both the low and high micro-albuminuria groups had significantly higher glycosylated haemoglobin levels and mean plasma glucose concentrations during a 24-h profile than their respective normo-albuminuric control subjects. A correlation between glycosylated haemoglobin level and urinary albumin excretion rate was found in the whole study group (r= 0.48; p< 0.001). Arterial pressure (both systolic and diastolic) was significantly higher in the high micro-albuminuria group than in either the control group or the low microalbuminuria group. A significant correlation was found between arterial pressure and albumin excretion rate in the whole study population (r= 0.49; p< 0.001) as well as in the pooled micro-albuminuria groups (r= 0.43; p< 0.05). Multiple regression analysis showed that glycosylated haemoglobin and arterial pressure levels were independently correlated with albumin excretion rates. Diabetic patients with micro-albuminuria of any degree have worse glycaemic control than normo-albuminuric patients. Higher levels of arterial pressure, though often sub-hypertensive, are associated with levels of micro-albuminuria predictive of later development of clinical proteinuria. Thus high plasma glucose and high arterial pressure, or both, characterise those diabetic patients at increased risk of nephropathy. These indices of risk are potentially reversible.