The benefits of angiotensin II receptor antagonists in high-risk hypertensive patients with diabetes

The coexistence of diabetes and hypertension portend increased macrovascula r and microvascular complications, with an increased risk for cardiovascula r death, including myocardial infarction, congestive heart failure, stroke and peripheral vascular disease. Several studies have reported that stringe nt blood pressure control reduces the risk of cardiovascular events and dia betes-related mortality. Additional benefits beyond those incurred from low ering blood pressure have been noted with the use of angiotensin-converting enzyme (ACE) inhibitors in high-risk groups. These effects are possibly du e to the benefits of blocking the renin-angiotensin system (RAS). ACE inhib itors have been shown to slow the progression of renal disease by slowing t he rate of decline of glomerular filtration and reducing proteinuria in pat ients with type 1 diabetes, and by slowing the progression of retinopathy i n normotensive diabetics. Preliminary data suggest that a new class of anti hypertensives, the angiotensin II receptor antagonists (AIIRAs), may reduce cardiovascular risk to at least the same extent as ACE inhibitors. The AII RA irbesartan has achieved superiority within its class because of the exte nt and duration of RAS blockade and antihypertensive efficacy. In animal mo dels of renal disease, irbesartan was found to produce significant dose-rel ated reductions in glomerular injury, prevent the development of proteinuri a and glomerulosclerosis, and normalize glomerular capillary pressure. The Program for Irbesartan Mortality and Morbidity Evaluations (PRIME) is an im portant research programme composed of two ongoing trials. The Irbesartan D iabetic Nephropathy Trial (IDNT) will assess the effects of irbesartan, the calcium channel blocker amlodipine or placebo (usual care) on cardiovascul ar morbidity and mortality and the progression of renal disease in high-ris k hypertensive patients with type 2 diabetes and proteinuria. The IRbesarta n MicroAlbuminuria (IRMA) II trial will assess the effects of irbesartan or placebo (usual care) on the progression of microalbuminuria to overt nephr opathy in hypertensive patients with type 2 diabetes, microalbuminuria and normal renal function. The results of these trials will be used to evaluate the cardiovascular and renal benefits of irbesartan in high-risk patients with hypertension and type 2 diabetes at both early and advanced stages of renal disease.