Urinary excretion of albumin in adolescents with type 1 diabetes: persistent versus intermittent microalbuminuria and relationship to duration of diabetes, sex, and metabolic control.

Abstract

Urinary excretion of albumin is a marker for incipient diabetic nephropathy in adults. The intra-individual variability, as well as the relationship to duration of diabetes, onset of the disease, and long-term metabolic control, have not been evaluated in a large sample of pediatric patients. A total of 5,722 nocturnal urinary albumin excretion rates were determined in 447 children, adolescents, and young adults with type 1 diabetes, comprising 1,821 years of observation. Excretion rates were related to duration of diabetes, age at onset of diabetes, sex, blood pressure, and metabolic control. Based on repeated measurements in individual patients, the positive predictive value of one sample was 76%, the negative 99.5%. After a duration of diabetes of 11 years, 5% of patients displayed persistent microalbuminuria (10% after 13 years). The duration of diabetes until persistent microalbuminuria was identical for patients with prepubertal or pubertal onset of diabetes. In addition to duration, female sex (P < 0.03) and insufficient long-term metabolic control (P < 0.03) contributed significantly and independently to urinary albumin excretion. Determination of urinary albumin excretion rate is useful in pediatric patients. Female subjects with a long duration of diabetes and insufficient metabolic control are especially at risk for microalbuminuria. Even if persistent microalbuminuria usually becomes evident in patients aged > 11 years, the prepubertal duration of diabetes contributes equally to this risk. Good metabolic control therefore should be aspired to from the onset of diabetes.