Intermittent diabetic microalbuminuria: Association with blood pressure, glycemic control, and protein intake

The factors associated with intermittent microalbuminuria were studied over 7 years in 49 Type I and 53 Type II diabetics who had normal initial albumin clearance. Fasting plasma glucose, HbA₁, 24 hour urinary glucose, blood pressure, protein intake (24 hour urinary urea), and the renal clearance of albumin, transferrin, and IgG, as well as total proteinuria, were assessed every 3-6 months. Fifteen Type I and 11 Type II diabetics had 40 and 31 episodes, respectively, of intermittent microalbuminuria, defined as an albumin clearance >11 nl/sec, without progressing to persistent microalbuminuria. Rises in transferrin and IgG clearance paralleled albumin clearance in both Type I and Type II diabetics. There were no significant changes in blood pressure or glycemic control during episodes of intermittent microalbuminuria. However, in Type I diabetics, intermittent microalbuminuria was associated with higher levels of urinary urea excretion. This study raises the possibility that increased protein intake may participate in the development of nephropathy in Type I diabetes.