Predictive value of albuminuria in American Indian youth with or without type 2 diabetes

OBJECTIVE: To examine the prognostic significance of elevated albu-minuria in youth with type 2 diabetes. PATIENTS AND METHODS: Cross-sectional and prospective studies were conducted on Pima Indian youth aged 5 to 19 years at baseline who were examined between July 1, 1982, and December 31, 2007. Prevalence and sequential changes in the level of microalbuminuria (30 < albumin-to-creatinine ratio [ACR] < 300 mg/g) and macroalbu-minuria (ACR > 300 mg/g) and incidence of macroalbuminuria were computed according to the presence or absence of type 2 diabetes. RESULTS: The prevalence of microalbuminuria and macroalbuminuria was 6.5% and 0.6% in the 3856 nondiabetic youth and 18.5% and 2.9% in the 103 youth with diabetes, respectively. One hundred forty-one of 187 (75.4%) nondiabetic youth, but only 1 of 14(7.1%)diabetic youth with an elevated ACR (>30 mg/g) regressed to an undetectable or normal ACR (<30 mg/g) on subsequent examination. In a subset of 2666 youth with a median follow-up of 8.1 years, 36 nondiabetic and 30 diabetic youth with baseline ACRs of <300 mg/g developed macroalbuminuria. For a given ACR, the incidence of macroalbuminuria was 15.9-fold (95% con-fidence interval: 11.1-22.6) higher in the diabetic than in the nondia-betic youth. CONCLUSIONS: Elevated albuminuria is infrequent and largely tran-sient in nondiabetic youth, but it is relatively frequent and largely per-sistent in those with diabetes. Microalbuminuria in youth with type 2 diabetes strongly predicts progression to macroalbuminuria, which supports annual screening for albuminuria.