Albuminuria and transferrinuria in essential hypertension. Effects of antihypertensive therapy.

The objectives of this study were to evaluate the effects of an ACE inhibitor (fosinopril) and a calcium antagonist (amlodipine) on the urinary albumin and transferrin excretion and their relationship to the blood pressure in essential hypertension. Twenty-four never-treated patients (mean age, 46.4 +/- 8.9 years) with a diastolic blood pressure between 90 and 114 mm Hg and normal renal function, randomly received amlodipine or fosinopril and, if the diastolic blood pressure was not normalized, doxazosin was added to the therapy. Twenty-four-hour ambulatory blood pressure monitoring and 24-h urine collection for albumin and transferrin measurements were performed before and after 3 and 6 months of therapy. Diastolic blood pressure was normalized in 23 patients (96%). Before treatment, microalbuminuria was present in 50% of patients. In the amlodipine and fosinopril group, antihypertensive therapy significantly decreased blood pressure and, only in the fosinopril group, albuminuria. Transferrinuria did not change significantly in both groups. Fosinopril lowered albuminuria in all patients, whereas amlodipine only in half of patients. Albuminuria, but not transferrinuria, was significantly correlated to the ambulatory blood pressure. This correlation was more pronounced for systolic than for diastolic pressure. In essential hypertensive patients with normal renal function, a high prevalence of microalbuminuria can be observed. Albuminuria appears to correlate with ambulatory blood pressure, particularly with systolic pressure. Intrarenal hemodynamic changes seem to play a more important role than systemic blood pressure decrease in the reduction of albuminuria. Transferrinuria does not seem a useful marker to follow-up nondiabetic hypertensive patients with early signs of glomerular dysfunction.