Are calcium antagonists beneficial in diabetic patients with hypertension?

PURPOSE We analyzed the available data to assess the effects of calcium antagonists in hypertensive patients with diabetes mellitus. METHODS We performed a MEDLINE search of English-language articles published until April 2003, using the terms diabetes mellitus, hypertension or blood pressure, and therapy. Pertinent articles cited in the identified papers were also reviewed. We included prospective randomized studies of more than 12 months' duration that evaluated the effect of drug treatment on morbidity and mortality in diabetic patients with hypertension. We estimated the effect of treatment with calcium antagonists on morbidity and mortality in comparison with placebo, conventional therapy, and therapy that blocks the renin-angiotensin system. RESULTS We identified 14 studies that reported outcomes in diabetic hypertensive patients. Compared with placebo, calcium antagonists reduced cardiovascular morbidity and mortality. Compared with conventional therapy, calcium antagonists had similar effects on coronary heart disease and total mortality, but may have reduced the risk of stroke (odds ratio [OR] = 0.87; 95% confidence interval [CI]: 0.74 to 1.02; P = 0.08). However, they resulted in a lesser reduction of the risk of heart failure (OR = 1.33; 95% CI: 1.17 to 1.50). Calcium antagonists were less effective than blockers of the renin-angiotensin system in preventing heart failure (OR = 1.43; 95% CI: 1.10 to 1.84), but had similar effects on stroke, coronary heart disease, and total mortality. CONCLUSION Calcium antagonists are safe and effective in reducing most types of cardiovascular morbidity and mortality in diabetic hypertensive patients, although their use is associated with a lesser reduction of risk of heart failure as compared with other treatments for hypertension.