Glycemic control and prognosis in type I diabetic patients with microalbuminuria

OBJECTIVE - To investigate the course of microalbuminuria during the 1980s in type I diabetes patients. RESEARCH DESIGN AND METHODS - This was a 10-year follow-up of 109 patients in whom type I diabetes was diagnosed between 1961 and 1980 before 15 years of age and who were initially investigated between 1977 and 1983 after a diabetes duration of greater than or equal to 3 years. Microalbuminuria was defined as an albumin excretion rate (AER) of 20-200 mu g/min in two of three consecutive urine samples. RESULTS - At the initial investigation, 81 patients had normal AER, 27 had microalbuminuria, and 1 had macroalbuminuria. Between 1989 and 1992, 99 (91%) patients were reinvestigated. Only 5 (19%) of the initially microalbuminuric patients developed macroproteinuria during the 10-year follow-up period, and in 15 (58%) patients, AER decreased to normal. Three (4%) of the normoalbuminuric patients developed microalbuminuria but none macroproteinuria. The initially microalbuminuric patients, in whom AER normalized, improved their glycemic control from 1980-1983 to 1989-1991 (mean +/- SEHbA(1c) 7.5 +/- 0.2 to 6.6 +/- 0.3%; P = 0.01). CONCLUSIONS - In the majority of patients with microalbuminuria in whom it is possible to obtain good glycemic control, microalbuminuria will disappear and the risk of developing nephropathy will be markedly reduced.