Microalbuminuria in insulin-dependent diabetes: prevalence and practical consequences.

Urinary albumin excretion in a representative sample of 679 patients with Type I (insulin-dependent) diabetes, 18 to 50 years of age, was investigated. Patients on antihypertensive therapy were excluded. Urinary albumin excretion was examined in one 24 hour urine sample using an ELISA technique. Twenty-three per cent of the patients had microalbuminuria, i.e., 30-300 mg albumin/24 h. The prevalence of microalbuminuria was independent of sex, age, insulin dose and diabetes duration. In the majority of those cases in which microalbuminuria was found during the first 10 years of diabetes, the concentrations were in the lower range, i.e., 30-50 mg/24 h. The prevalence of incipient nephropathy (urinary albumin excretion in a single urine sample of 51-300 mg/24 h) increased with diabetes duration. In patients with incipient nephropathy hemoglobin A1c tended to be, and blood pressure was, elevated compared with age, sex, and duration matched patients with normal urinary albumin excretion rates (p = 0.08 and p less than 0.001, respectively). Urinary albumin excretion and blood pressure were significantly correlated in the total group (n = 401, r = 0.2, p less than 0.001). On the basis of these findings practical guidelines for the handling of patients with microalbuminuria are proposed.