Extracellular volume and aldosterone interaction in chronic kidney disease.

Since the advent of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, little attention has been given to the potential proinflammatory effects of aldosterone in high-volume states on the kidney and cardiovascular system. In order to be correctly interpreted, aldosterone levels require a volume cofactor which can now be determined by measurement of extracellular fluid volume by means of bioimpedance. Chronic kidney disease patients frequently have expanded extracellular volume (ECV) in the presence of elevated aldosterone levels. This combination may lead to cardiovascular and renal inflammation and fibrosis that can be mitigated by more precise control of ECV and/or blockade of the mineralocorticoid receptor.

Change in proteinuria after adding aldosterone blockers to ACE inhibitors or angiotensin receptor blockers in CKD: a systematic review.

BACKGROUND: The use of mineralocorticoid receptor blockers (MRBs) in patients with chronic kidney disease is growing, but data for efficacy in decreasing proteinuria are limited by a relative paucity of studies, many of which are small and uncontrolled. STUDY DESIGN: We performed a systematic review using the MEDLINE database (inception to November 1, 2006), abstracts from national meetings, and selected reference lists. SETTING & POPULATION: Adult patients with chronic kidney disease and proteinuria. SELECTION CRITERIA FOR STUDIES: English-language studies investigating the use of MRBs added to long-term angiotensin-converting enzyme (ACE)-inhibitor and/or angiotensin receptor blocker (ARB) therapy in adult patients with proteinuric kidney disease. INTERVENTION: MRBs as additive therapy to conventional renin-angiotensin-aldosterone system blockade in patients with chronic kidney disease. OUTCOMES: Changes in proteinuria as the primary outcome; rates of hyperkalemia, changes in blood pressure, and changes in glomerular filtration rate as secondary outcomes. RESULTS: 15 studies met inclusion criteria for our review; 4 were parallel-group randomized controlled trials, 4 were crossover randomized controlled trials, 2 were pilot studies, and 5 were case series. When MRBs were added to ACE-inhibitor and/or ARB therapy, the reported proteinuria decreases from baseline ranged from 15% to 54%, with most estimates in the 30% to 40% range. Hyperkalemic events were significant in only 1 of 8 randomized controlled trials. MRB therapy was associated with statistically significant decreases in blood pressure and glomerular filtration rate in approximately 40% and 25% of included studies, respectively. LIMITATIONS: Reported results were insufficient for meta-analysis, with only 2 studies reporting sufficient data to calculate SEs of their published estimates. We were unable to locate studies that showed no effect of MRB treatment over placebo, raising concern for publication bias. CONCLUSIONS: Although data suggest that adding MRBs to ACE-inhibitor and/or ARB therapy yields significant decreases in proteinuria without adverse effects of hyperkalemia and impaired renal function, routine use of MRBs as additive therapy in patients with chronic kidney disease cannot be recommended yet. However, the findings of this review promote interesting hypotheses for future study.