Role of angiotensin receptor blockers in diabetes: implications of recent clinical trials

Hypertension is a comorbidity of Type 2 diabetes, and blood pressure lowering has been shown to reduce cardiovascular (CV) and renal disease progression in this population. Angiotensin-converting enzyme (ACE)-inhibitors have demonstrated reduction in CV mortality and myocardial infarction, stroke, and heart failure in patients with diabetes. Evidence suggests that angiotensin receptor blockers (ARBs) have similar CV protective effects, particularly in patients post-myocardial infarction and in those with heart failure, and their renoprotective effects have reduced proteinuria in patients with or without diabetes. In addition, ARBs have been shown to reduce diabetic nephropathy and complications related to nephropathy. The Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint trial (ONTARGET) is the first trial to demonstrate that the ARB, telmisartan, is as effective as the ACE-inhibitor, ramipril, in CV protection in a high-risk, ACE-tolerant population. Whether all ARBs are equally cardioprotective is uncertain. Data indicate that the beneficial effects of telmisartan may be drug specific rather than constitute a 'class effect.'