Microalbuminuria in long-term insulin-dependent diabetes mellitus. Prevalence and clinical characteristics in a normotensive population.

Albumin excretion rate was determined by radioimmunoassay in overnight urine from 102 normotensive patients with insulin-dependent diabetes mellitus of more than 10 year's duration. Based on two samples, 16 patients (16%) exhibited microalbuminuria, defined as a mean excretion rate greater than 20 micrograms/min. Microalbuminuric patients were significantly younger at onset of diabetes but did not differ from normoalbuminuric patients concerning age or duration of diabetes. Nonetheless, diastolic and mean arterial blood pressures were significantly higher in the microalbuminuric group. The existing glycemic control, assessed by glycosylated hemoglobin (HbA1c) was better in normoalbuminurics, but not significantly so. The albumin excretion rate in microalbuminuric patients correlated significantly (p less than 0.01) to diastolic (r = 0.69) and to mean arterial blood pressure (r = 0.69), but did not correlate to HbA1c. Thus, it is concluded that even normotensive patients with signs of early diabetic nephropathy, i.e. microalbuminuria, exhibit small, but significant increases in blood pressure.