Optimizing antihypertensive therapy in patients with diabetic nephropathy.

The number of cases of diabetic nephropathy is increasing, especially among patients with non-insulin-dependent diabetes mellitus (NIDDM). It is difficult to prevent the occurrence or progression of NIDDM, and current levels of treatment are below standard. According to one study, actuarial 5-year survival rates are only about 38% for patients with insulin-dependent diabetes mellitus and 9% for those with NIDDM receiving renal replacement therapy. Because cardiovascular diseases are responsible for more than half of these deaths, hypertension, as a major contributing factor to cardiac death, is a crucial component in the therapy for such patients. It is well established that lowering blood pressure is an important preventive measure to be taken in patients with diabetic nephropathy; blockade of the renin-angiotensin system offers benefits beyond lowering blood pressure in type I diabetic nephropathy. Two major trials are currently underway to determine the effects of angiotensin II receptor antagonists on nephropathy in patients with NIDDM. The Irbesartan Diabetic Nephropathy Trial (IDNT) has already enrolled approximately 85% of the proposed 1650 NIDDM patients to be randomly assigned to placebo, irbesartan or amlodipine. Baseline characteristics of the initial cohort are presented. In light of the well-documented case for blockade of the renin-angiotensin system in diabetes, the potentially superior blockade afforded by angiotensin II receptor antagonists, and the superior tolerability of these agents, trials such as the IDNT take on special importance for the treatment of diabetic patients. From these data may come the justification for the belief that angiotensin II receptor antagonists impart greater benefits in the treatment of diabetes than merely their well-documented role in lowering blood pressure.