<qa>  What is the main role of aldosterone in promoting progressive renal dysfunction?Plasma aldosterone concentrations are increased in animal models of CRF as well as in patients with even mild renal impairment and several lines of evidence point to a major role of aldosterone in promoting progressive renal dysfunction. Observational studies in patients with primary hyperaldosteronism found the prevalence and degree of proteinuria to be greater than in patients with essential hypertension. Several experimental animal models are consistent with the concept that aldosterone can mediate renal injury. In patients with diabetic nephropathy and aldosterone escape despite ACE inhibitor therapy, aldosterone blockade significantly reduced proteinuria with no change in blood pressure. Little attention has been paid however, to the potentially beneficial effects of aldosterone antagonism on the cardiovascular system in renal failure. In a single, small uncontrolled study of 13 patients with diabetic nephropathy on established ACE inhibitor therapy, left ventricular mass index was significantly reduced after 24 weeks of treatment with spironolactone. 