Inhibitors of the renin-angiotensin system reduce the rate of GFR decline and end-stage renal disease in patients with severe renal insufficiency.

Drugs that inhibit the renin-angiotensin system (RAS) are of proven benefit in the treatment of hypertension, congestive heart failure, or acute myocardial infarction. In the last decade, several clinical trials have shown that RAS inhibitors also offer significant renoprotection in both diabetic and non-diabetic nephropathy. However, patients with advanced renal insufficiency did not take part in these trials because of the risk of acute renal failure (ARF) and hyperkalemia, and, for the same reason, most physicians do not offer these drugs to patients with impaired renal function. Recently, a post-hoc analysis of the Ramipril Efficacy In Nephropathy (REIN) study which included patients with severe renal insufficiency, showed that RAS inhibition slows glomerular filtration rate (GFR) decline over time and progression to end-stage renal disease (ESRD) in a safe way in patients quite close to ESRD (basal GFR, 10 to 30 ml/min/1.73m2). These beneficial effects have also been shown in the Reduction of Endpoints in NIDDM with the All Antagonist Losartan (RENAAL) study, in patients with type 2 diabetes mellitus, clinical proteinuria, and renal insufficiency, where RAS inhibition therapy significantly reduced the risk of ESRD once doubling of baseline serum creatinine levels had been achieved as compared to non-RAS anti-hypertensive treatment. Thus, these data suggest that RAS inhibition therapy should be given to all patients with proteinuric chronic nephropathy, independently of the level of renal function.