Angiotensin-converting enzyme inhibition and diabetic nephropathy.

Hypertension and diabetes mellitus are strongly associated conditions from epidemiologic, genetic, and pathophysiologic points of view. The prevalence of hypertension is high in patients with diabetes, and, conversely, many patients with essential hypertension are glucose intolerant. Proteinuria appears in 40-50% of patients with insulin-dependent diabetes mellitus and 20-30% of patients with non-insulin-dependent diabetes mellitus. Progressive renal failure occurs in 30-40 and 3-8% of patients, respectively, hypertension being a leading factor in its rate of progression. In various animal experiments, ACE inhibitors are able to prevent proteinuria and glomerular sclerosis, presumably by lowering transglomerular capillary pressure. In the diabetic human, ACE inhibitors are powerful antihypertensive drugs, devoid of metabolic side effects. Clinical studies indicate that ACE inhibitors reduce proteinuria and possibly slow the rate of decline in renal function. Such an effect is not observed with beta-blockers. Large-scale studies are needed to confirm this very important hypothesis.