A new study has shown for the first time that drugs can safely and significantly reduce the number of strokes and heart attacks in people over 60 who are increasingly vulnerable to an age-related high blood pressure.
The five-year national clinical trial was hailed yesterday as "a landmark study" by Dr. John Kostis, principal investigator and chairman of medicine at the Robert Wood Johnson Medical School at the University of Medicine and Dentistry of New Jersey.
It could improve the outlook for about 3 million to 4 million older people with a specific type of elevated pressure called isolated systolic hypertension, or ISH, he said.
Dr. Thomas R. Price, a University of Maryland Medical Center neurology professor who was a consultant on the study, said the findings are particularly important because it is estimated that by the year 2000 there may be as many as 10 million people living with ISH and at risk for catastrophic diseases.
"There's nothing like preventing a stroke, I'll tell you," said Price, who directs the UM Stroke Center. "You can't see it, but you know there are some people out there who are a lot better off just from being in the study."
In the trial that studied 4,736 people, drug treatment cut the incidence of stroke -- non-fatal and fatal -- by 36 percent, the equivalent of 30 fewer strokes per 1,000 people over five years. Major cardiovascular events, such as heart attacks, were reduced by 32 percent. The death rate from all causes was 18 percent lower.
The results are published in today's edition of the Journal of the American Medical Association. The study was funded by National Heart, Lung and Blood Institute and the National Institute on Aging of the National Institutes of Health.
The researchers reported the results were achieved with a minimum of side effects and no evidence of an increase in mental confusion or depression.
ISH is common, affecting those in their 60s, 70s and 80s in increasing numbers. At least 20 percent of those over age 80 have the condition, which causes only their systolic pressure to increase.
The systolic pressure -- the higher and top number of the blood pressure reading -- measures the pressure when the heart beats. The diastolic pressure -- the lower number of the reading -- measures the pressure when the heart rests.
Traditionally, ISH has been associated with a two- to-three times higher risk of stroke and increased risk of coronary heart disease, heart failure, heart attack and sudden death from cardiovascular disease.
Until now, ISH had always been regarded as a natural consequence of aging, "something that we could do nothing about," said Price. "But, now we know differently and it's such good news."
Kostis explained that diastolic pressure usually increases with age, stabilizing at about 60, but systolic pressure continues to rise as the arteries stiffen. "This study has shown that we can now treat this condition effectively, too, with a diuretic used for diastolic hypertension," he said.
The mean age of those who enrolled in the study at 16 medical centers across the country was 72 years; 57 percent were women and 14 percent were black.
A total of 2,365 participants received drug treatment and another 2371 were given a placebo, or dummy medication. The systolic blood pressure ranged from 160 to 219 millimeters of mercury and the diastolic blood pressure was less than 90 millimeters of mercury.
The five-year average systolic blood pressure was 155 millimeters of mercury for the placebo group and 143 millimeters of mercury for the drug treatment group. The five-year average ++ diastolic pressure was 72 millimeters of mercury for the placebo group and 68 millimeters of mercury for the drug treatment group.