Management of hypertension in the patient with diabetes mellitus. Focus on the use of angiotensin-converting enzyme inhibitors.

Abstract

Hypertension in patients with diabetes mellitus increases the risk of both macrovascular and microvascular complications. Such microvascular complications as diabetic nephropathy and retinopathy are accelerated in the presence of arterial hypertension. Evidence suggests that the complications of diabetes mellitus begin early in the course of the disorder as manifested by microalbuminuria and increased vascular reactivity. These findings are accompanied by changes in the renin-angiotensin-aldosterone system including reductions in plasma renin activity. These changes could be secondary to volume expansion that may be a direct consequence of elevated blood glucose, suggesting that the metabolic disorder in diabetes contributes to the etiology of hypertension in these patients. Adequate treatment of hypertension is crucial to the prevention of complications; however, many antihypertensive agents have limited usefulness in diabetes mainly because of their unfavorable side effects. Diuretics lower blood pressure in hypertensive diabetics, but their metabolic effects are especially undesirable in this population. beta-Blockers alter glucose and lipid metabolism in diabetic patients and reduce regional blood flow. Central acting agents and alpha-blockers are often associated with orthostatic hypotension, sexual dysfunction, and central nervous system side effects. Angiotensin-converting enzyme inhibitors (ACEIs) such as captopril effectively lower blood pressure in diabetic patients and have few unwanted effects. They may improve metabolic control and have favorable effects on glucose metabolism. The ACEIs also produce improved regional hemodynamics which may lead to the improvement in or prevention of the progression of diabetic nephropathy.