By: Thomas Pickering, MD, DPhil, FRCP, Director of Integrative and Behavioral Cardiology Program
of the Cardiovascular Institute at Mount Sinai School of Medicine, New York.

Calcium channel blockers have received very mixed press reports in the past few years; some reports suggest that they may not be good for patients who have diabetes in conjunction with hypertension. The most conclusive study to date has been Syst-Eur.

In this study the effects of a long-acting calcium channel blocker called nitrendipine were compared against a placebo (inert pills) in 4,695 elderly patients with systolic hypertension (a high systolic pressure but normal diastolic pressure). This study showed conclusively that the calcium channel blocker treatment reduced both strokes and heart attacks.

A new analysis from the same study has looked at the effects of treatment in patients who had diabetes as well as hypertension. The results were dramatic. In the diabetics mortality from heart attacks was reduced by 63%, the number of strokes was reduced by 76%. However, in the non-diabetics, mortality from heart attacks was reduced by 21% percent, and the number of strokes was reduced by 38%. In the placebo-treated group, the mortality rate was higher for the diabetics than in those without diabetes, but in the treated group, it was the same in both diabetics and non-diabetics. Thus, the extra risk that diabetes adds to hypertension was wiped out by treatment with the calcium channel blocker.

Doctor’s comments

This is a very important finding. It is well known that the combination of diabetes and high blood pressure is bad, as was seen in the placebo group of this study. The only other comparable study of treatment of systolic hypertension in older people was called SHEP (Systolic Hypertension in the Elderly Program). The study was based on treatment with a diuretic and found much the same benefits of treating people without diabetes as Syst-Eur, but the reduction of combined cardiovascular events was much less in diabetics in SHEP (34%) than in Syst-Eur (68%). Not only do the Syst-Eur results dispel the idea that calcium channel blockers are unsafe in elderly diabetics, but they also suggest that calcium channel blockers should be the treatment of choice in people who are over 60, have systolic hypertension, and diabetes. Nitrendipine is not available in the U.S. The equivalent drugs are Norvasc (amlodipine), Procardia XL (nifedipine), Sular (nisoldipine), and Plendil (felodipine).

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