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.

Trials that have proven that lowering blood pressure prevents strokes and heart attacks have most often used beta-blockers and diuretics. Although both have been widely advocated as first line treatment for hypertension, the latest US national recommendations (called JNC VI) no longer recommend beta-blockers for older people. A recent analysis provides support for this view. Dr. Franz Messerli and his colleagues analyzed the results of all the clinical trials that have compared the effects of beta-blockers and diuretics in preventing strokes and heart attacks in people with high blood pressure over the age of 60. There were 10 such studies in all, which together included 16,164 patients. The process of combining the results of different trials is called a meta-analysis.

The analysis showed that diuretics were more effective in controlling the blood pressure - two thirds of the patients had their pressure normalized with a diuretic alone, whereas only one third were controlled by a beta blocker alone.

The mortality from all causes was reduced by diuretics alone (by 14%), whereas beta-blockers had no effect. Diuretics reduced the probability of having a stroke by 39% and beta blockers by 26%, and diuretics reduced heart attacks by 26%, while beta blockers had no effect. For the patients who were treated with a combination of the two, the reduction of strokes and heart attacks was intermediate - not as good as diuretics alone but better than beta blockers alone.

Doctor's comments

This analysis confirms the results of the individual trials and reinforces the argument that beta blockers should not be used as first-line treatment in older people. This is in contrast to people under the age of 60, for whom there is good evidence that both classes of drugs are effective. Part of the explanation may be that, in the elderly, beta blockers do not lower blood pressure as well as diuretics. Another may be that the mechanism of hypertension is different in older than in younger people. In the elderly, the blood pressure is high not because the heart is pumping more blood, but because the resistance to flow is increased by constriction of the arteries; beta blockers act by lowering the amount of blood pumped by the heart and may actually constrict the arteries further.

Where it was published