Effects of improved glycemic control on microalbuminuria in adolescents with insulin-dependent diabetes mellitus.

The effect of improved glycemic control on microalbuminuria was evaluated longitudinally in 13 adolescents with insulin-dependent diabetes mellitus (IDDM) of 8.4 +/- 0.8 years duration. Glycemic control and microalbuminuria were assessed under three treatment regimens: conventional therapy (Period A); after 6 weeks of intensified conventional therapy (Period B); and at three periods during continuous subcutaneous insulin infusion (CSII) (Period C = 10-14 days, Period D = 2-4 months, and Period E = 6-8 months, of CSII). Although euglycemia was not achieved, there was a decrease in mean 24-hour blood glucose concentrations measured hourly in the hospital, with values averaging 239 mg/dl in Period A, 202 mg/dl in Period B, and 156-184 mg/dl in Periods C to E. This was accompanied by significant reductions in the values for whole blood, and to a lesser extent, in stable glycosylated hemoglobin A1 (GHbA1) (p less than 0.05), but not in creatinine clearance, albumin clearance, or in albumin excretion rate. Significant correlations were found between whole blood GHbA1 levels and albumin clearance in each of Periods B to E and between albumin clearance and albumin excretion in Periods B to D (p less than 0.05) but not in Period A. Our data suggests that the degree of improvement in glycemic control obtained in our adolescent population with IDDM using either intensive conventional therapy or CSII does not reduce the microalbuminuria. If modulation of microalbuminuria is achievable it may require euglycemia or may involve other factors which have a more direct effect on the transit of albumin across the glomerular basement membrane.