The role of angiotensin II receptor blockers in preventing the progression of renal disease in patients with type 2 diabetes

Diabetes mellitus is the most common cause of end-stage renal disease in the United States, accounting for about 50% of all new cases. Although we previously established the renoprotective benefits of angiotensin converting enzyme (ACE) inhibitors in patients with coexisting hypertension and type 1 diabetes, evidence of the renoprotective effect of ACE inhibitors in patients with type 2 diabetes is less clear. We conducted the Irbesartan Diabetic Nephropathy Trial (IDNT) to determine whether the angiotensin II receptor blocker (ARB) irbesartan slows the progression of nephropathy in patients with type 2 diabetes independently of its blood pressure (BP)-lowering effect. In this randomized, controlled trial, we found that irbesartan was associated with a 20% reduction in the risk for the primary composite end point (doubling of the baseline serum creatinine concentration, development of end-stage renal disease, or death from any cause) compared with placebo (P = .02) and a 23% reduction compared with amlodipine therapy (P = .006). These results were not explained by differences in the BP that was achieved. In a separate study, losartan was shown to reduce the risk for progression of renal disease in patients with type 2 diabetic nephropathy. Angiotensin II receptor blocker therapy has also been demonstrated to slow the progression to overt nephropathy when initiated early in the course of type 2 diabetic renal disease (ie, in patients with microalbuminuria). Based on these studies, ARBs are clearly effective in protecting against the progression of nephropathy due to type 2 diabetes. This protection is independent of their BP-lowering effect. Preclinical studies with the newest ARB, olmesartan medoxomil, suggest that this agent may provide renoprotective benefits as well. (C) 2002 American Journal of Hypertension, Ltd.