Progression of proteinuria in type 1 and type 2 diabetes.

A longitudinal study evaluating the time course of the transition from normal to microalbuminuria, and then on to macroalbuminuria, was made over a mean period of 7 years in a cohort of 52 patients with Type 1 diabetes and 61 patients with Type 2 diabetes. Transient episodes of micro- and macroalbuminuria were often observed before the ultimate development of persistent Albustix-positive proteinuria. The transition from normal to microalbuminuria and from micro- to macroalbuminuria was characterized by rises in renal albumin clearance accompanied by lesser rises in total proteinuria. Seven patients with Type 1 and 12 with Type 2 diabetes showed evidence of progression, the interval for the transition from normal to macroalbuminuria varying from 3 to 5 years. In Type 1 diabetic patients, the development of micro- and macroalbuminuria was associated with a decline in renal function and a rise in systolic blood pressure without a significant change in blood glucose control. In Type 2 diabetic patients, the development of microalbuminuria was associated with a small decline in renal function but no change in blood pressure or blood glucose control. It is concluded that the transition from normal to micro- and on to macroalbuminuria may be more rapid then previously reported and varies considerably among individuals.