Triphasic changes in selectivity with increasing proteinuria in type 1 and type 2 diabetes.

Abstract

Two indices of the selectivity of proteinuria, the immunoglobulin G (IgG)/albumin and the IgG/transferrin clearance ratios, were studied cross-sectionally and serially over 7 years in a cohort of 52 Type 1 and 60 Type 2 diabetic patients without established diabetic nephropathy. In Type 1 and Type 2 diabetic patients with albuminuria less than 30 micrograms min-1, both protein clearance ratios were significantly higher than in 27 control subjects. As albuminuria increased, there was a decrease in both protein clearance ratios. However, at albumin clearances above 90 nl s-1, equivalent to albumin excretion rates of greater than 250 micrograms min-1, a positive correlation was found in Type 2 ..