Microalbuminuria in Patients With Essential Hypertension

Several patients with essential hypertension manifest an abnormal (greater than 30 mg/24 h) urinary albumin excretion (UAE). Since microalbuminuria is considered an independent predictor of cardiovascular morbidity and mortality, studies are currently being undertaken to determine the effect of various antihypertensive agents on UAE, on the assumption that a reduction of UAE might result in improved prognosis in patients with essential hypertension. Twenty-four patients with essential hypertension were randomly divided into two groups of 12. The first group received 20 mg/day enalapril for 8 weeks, followed by 20 to 40 mg/day nitrendipine for 8 more weeks. The second group received nitrendipine for 8 weeks, followed by enalapril. Mean arterial pressure decreased similarly during both therapeutic regimens in the two groups of patients. In patients of group 1, UAE decreased significantly (P less than .01) from 74 +/- 7.0 to 33 +/- 5.8 mg/24 h after 8 weeks of treatment with enalapril; during the following 8 weeks of treatment with nitrendipine, UAE increased to 58 +/- 5.3 mg/24 h (P less than .02). In patients of group 2, UAE did not change during the first 8 weeks of therapy with nitrendipine despite a significant reduction in blood pressure; subsequently, after 8 weeks of therapy with enalapril, UAE decreased from 62 +/- 9.2 to 31 +/- 4.8 mg/24 h (P less than .01). This study demonstrates that enalapril but not nitrendipine may reduce UAE in patients with essential hypertension despite similar antihypertensive efficacy. The significance of microalbuminuria and the impact of the normalization of UAE on cardiovascular morbidity and mortality in patients with essential hypertension remains to be determined.