Rationale and design of a study to evaluate management of proteinuria in patients at high risk for vascular events: the IMPROVE trial

Declining kidney function predicts increasing cardiovascular risk in people with hypertension. Microalbuminuria is a marker for cardiovascular risk and declining kidney function. Agents that block the renin-angiotensin-aldosterone system (RAAS), notably angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), reduce proteinuria and microalbuminuria, lower blood pressure and slow the progression of proteinuric kidney disease. Evidence is accumulating that the combination of an ACE inhibitor and an ARB is the optimal means of RAAS blockade in this setting, slowing the progression of nephropathy independently of blood pressure lowering to a greater degree than can be achieved using maximum approved doses of either agent alone. However, the emerging therapeutic potential of ACE inhibitor/ARB combination therapy in hypertensive kidney disease requires further characterization. The Irbesartan in the Management of PROteinuric patients at high risk for Vascular Events trial aims to determine definitively whether the combination therapy of an ARB, irbesartan and an ACE inhibitor, ramipril, is more effective than ramipril alone in reducing the urinary albumin excretion rate in patients at high cardiovascular risk with hypertension and proteinuria or microalbuminuria.