Ambulatory blood pressure, microalbuminuria, and autonomic neuropathy in adolescents with type 1 diabetes

OBJECTIVE - To examine the relationship between 24-h blood pressure (BP) me asurements, urinary albumin excretion rates, and autonomic neuropathy (AN) in adolescents with type 1 diabetes. RESEARCH DESIGN AND METHODS - A total of 31 patients with microalbuminuria (MA), 20 patients with intermittent MA (I-MA) and 11 patients with persiste nt MA (P-MA) were identified from the diabetes clinics at two major Austral ian tertiary care pediatric hospitals, Two control groups were used; one co nsisted of 19 age-, sex-, and diabetes duration-matched adolescents with no rmoalbuminuria (NA), and the other consisted of 46 age and sex-matched nond iabetic control subjects. A medical history and physical examination were f ollowed by a series of noninvasive tests of cardiovascular and pupillary au tonomic function and then by 24-h ambulatory blood pressure monitoring (ABP M). RESULTS - ABPM showed an incremental increase in all BP parameters from non diabetic control subjects through subjects with NA. A parallel incremental increase in diurnal and nocturnal ambulatory heart rates was also evident. Subjects with MA had significantly reduced pupillary adaptation to darkness compared with nondiabetic subjects and subjects with NA. The above results paralleled an incremental increase in HbA(1c) levels in adolescents with t ype 1 diabetes from subjects with NA to subjects with P-MA. CONCLUSIONS - Higher 24-h BP values and evidence of subclinical signs of AN are present before P-MA develops and may have important implications for t iming the introduction of treatments designed to prevent or retard the micr ovascular complications of type 1 diabetes in adolescents.