Low prevalence of microalbuminuria in normotensive patients with insulin-dependent diabetes mellitus

We studied the prevalence of microalbuminuria (urinary albumin excretion rate [UAER] >20 μg/min ≤200 μg/min) as determined in a single, timed, overnight urine collection in 156 normotensive (BP< 140 90), Albustix^® negative subjects with type 1 diabetes and its association with arterial blood pressure, the duration of diabetes, levels of glycosylated hemoglobin, body mass index, daily insulin dose and serum cholesterol. Nineteen subjects (12.2%) had a UAER in the microalbuminuric range. The microalbuminuric patients had a significantly longer duration of diabetes, 21±2 vs 15±1 years (P<0.01), higher diastolic blood pressure, 80 ± 2 vs 76 ± 1 mmHg (P < 0.05) and serum cholesterol concentration, 206 ± 11 vs 186 ± 3 mg/dl (P < 0.05) than did the normoalbuminuric subjects. There were no differences between the normoalbuminuric and microalbuminuric subjects in terms of age, systolic blood pressure, body mass index, daily insulin dose or glycosylated hemoglobin levels. These data indicate that the prevalence of microalbuminuria in type 1 diabetes has probably been overestimated in previous studies due to the inclusion of patients with hypertension. Thus, microalbuminuria, rather than being a predictor of the development of diabetic renal disease, may indicate the presence of diabetic nephropathy with rising blood pressure levels. Further investigation is needed to clarify the relationship between microalbuminuria and coronary risk factors such as serum cholesterol and diastolic blood pressure levels.