DETERMINANTS OF PROGRESSION OF MICROALBUMINURIA IN ADOLESCENTS WITH IDDM

OBJECTIVE - To evaluate the significance of microalbuminuria in adoles cents with IDDM and to study the relative importance of blood pressure (BP), metabolic control, and albumin excretion rate (AER) on progress ion of microalbuminuria.RESEARCH DESIGN AND METHODS - A cohort of 155/ 156 children and adolescents followed from onset up to 18.3 years of I DDM participated. In a previous Follow-up in July 1991 (up to 15 years of duration), 17 patients had developed persistent microalbuminuria ( greater than or equal to 20 mu g/min). In these adolescents, we analyz ed whether microalbuminuria had progressed (in mean greater than or eq ual to 5% per year), had remained unchanged, or had normalized (<20 mu g/min) after another 3 years. The predictive values of mean HbA(1c) d iastolic blood pressure (dBP), systolic blood pressure (sBP), overnigh t AER, sex, age, and duration of diabetes for the progression of micro albuminuria were determined using multiple regression modeling. RESULT S - Seven of 17 patients with microalbuminuria in July 1991 had normal ized, 6 of 17 patients had progressed, and 4 of 17 patients had remain ed unchanged after 3 years. Progressors had higher mean HbA(1c) during the first 5 years of IDDM and higher mean sBP in 1991 than nonprogres sors. Patients with normalized microalbuminuria all had AER <30 mu g/m in in 1991, were younger at onset of microalbuminuria, had lower mean HbA(1c), and had lower dBP before normalized AER than nonregressors at the same duration of microalbuminuria. In multivariate analysis, inde pendent significant predictors for progression were first 5-year mean HbA(1c), mean AER, and mean sBP in 1991 (R(2) = 0.76, P = 0.001). CONC LUSIONS - Progression of microalbuminuria in adolescents with IDDM is predicted by early sustained hyperglycemia, later elevated sBP, and in creased AER per se. Microalbuminuria is frequently normalized in adole scents, and this is associated with better prevailing metabolic contro l, younger age, and lower dBP.