Experimental evidence suggests that aldosterone contributes to progressive kidney disease. Angiotensin-converting enzyme inhibitors and angiotensin type 1 receptor antagonists suppress the renin-angiotensin system but they do not effectively reduce plasma aldosterone. Hence, administration of aldosterone receptor antagonists may provide additional renal protection. In the present prospective randomized open-label study, we evaluated the effects of spironolactone (25 mg/day for 1 year) on proteinuria and estimated glomerular filtration rate in 83 patients with chronic kidney disease already treated with angiotensin-converting enzyme inhibitors and/or angiotensin type 1 receptor antagonists. Eighty-two patients were treated with angiotensin-converting enzyme inhibitors and/or angiotensin type 1 receptor antagonists alone and served as controls. After 1 year of therapy, proteinuria decreased from 2.1+/-0.08 to 0.89+/-0.06 g/g creatinine (P<0.001) in patients treated with spironolactone, but it did not change in control patients. Baseline aldosterone levels were significantly correlated with proteinuria (r=0.76, P<0.0001), and predicted the degree of reduction in proteinuria with spironolactone (r=0.42, P<0.0002). Baseline estimated glomerular filtration rate was similar in patients treated with spironolactone and controls (62.4+/-2.4 and 62.2+/-2.1 ml/min/1.73 m(2), respectively). After 1 month of therapy with spironolactone, estimated glomerular filtration rate decreased more in patients treated with spironolactone than in controls. However, by the end of 1 year the monthly rate of decrease in estimated glomerular filtration rate from baseline was lower in patients treated with spironolactone than in controls (0.323+/-0.044 vs 0.474+/-0.037 ml/min/1.73 m(2), P<0.01). Spironolactone caused a significant rise in serum potassium levels (from 4.2+/-0.04 at baseline to 5.0+/-0.05 mEq/l after 12 months of treatment, P<0.001). In conclusion, this study has shown that spironolactone may reduce proteinuria and retard renal progression in chronic kidney disease patients.

This study suggests that hypertensive individuals with microalbuminuria manifest a greater incidence of cardiovascular events and a greater decline in renal function than do patients with normal UAE.

No abstract

Microalbuminuria has been shown in approximately 40% of patients with essential hypertension. Previous studies have failed to demonstrate any consistent relationship between microalbuminuria and levels of office blood pressure. Because average ambulatory blood pressure correlates with incidence of cardiovascular morbidity and mortality better than office blood pressure, we have studied whether levels of urinary albumin excretion correlate with average diurnal, nocturnal, or 24-h blood pressure better than with office blood pressure. Sixty-three patients with essential hypertension and 21 healthy volunteers were included in the study. Twenty-four hypertensive patients failed to show the normal nighttime fall in blood pressure of at least 10/5 mm Hg and were defined as "nondippers"; the remaining were defined as "dippers." Office blood pressure was not different between dippers and nondippers. However, nighttime systolic and diastolic blood pressures were significantly greater in nondippers than in dippers. The median urinary albumin excretion in nondippers (42 mg/24 h) was significantly greater (P < .001) than in dippers (17.5 mg/24 h), and in normal subjects (8.6 mg/24 h). A significant correlation was present between nighttime systolic and diastolic blood pressure and urinary albumin excretion (UAE) and between 24-h systolic blood pressure and UAE in all hypertensive patients; in addition, a significant correlation was present between 24-h diastolic and nighttime diastolic blood pressure and UAE in nondippers. The increased amount of UAE in nondipper hypertensive patients suggests the presence of greater renal damage than in dippers.