Objective: To compare the effects of standard therapy (diuretic, beta-blocker or both) with those of angiotensin converting enzyme (ACE) inhibition with quinapril on renal function and urinary albumin excretion in patients with essential hypertension.
Methods: A 1-year, placebo-controlled, randomly allocated study was conducted in a group of 40 patients with essential hypertension. Before beginning the active treatment phase, all patients were given a matched placebo for quinapril for at least 14 days. At baseline and after 1, 3, 6 and 12 months of treatment, blood pressure, heart rate, body weight, renal plasma flow, glomerular filtration rate, plasma renin activity, plasma aldosterone and urinary albumin excretion were measured.
Results: Both the standard therapy and quinapril produced similar decreases in blood pressure, but only quinapril produced a significant decrease in micro-albuminuria, from 68.5 +/- 16.7 to 47.2 +/- 14.9 mg/24 h (P < 0.05). The renal plasma flow remained constant in both study groups while the glomerular filtration rate and filtration fraction decreased significantly (P < 0.05) in the quinapril group.
Conclusions: The results of this study indicate that long-term therapy for essential hypertension with ACE inhibition has a more favorable effect on micro-albuminuria than standard therapy for an equal level of blood pressure control.