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Drugs slash stroke risk for elderly.

Treating an age-related type of high blood pressure with drugs cuts the risk of debilitating stroke by more than one-third in people age 60 and older, according to the results of a long-awaited five-year study. The findings may provide dramatic benefits for aging baby boomers, who are expected to develop the life-threatening condition in record numbers by the turn of the century.

"This finding is absolutely extraordinary," says Jeremiah Stamler, a coauthor of the new study. "It's one of the most exciting trials we've ever been involved in," adds Stamler, a long-time hypertension researcher at Northwestern University Medical School in Chicago.

About 7 percent of all people age 60 to 69 develop isolated systolic hypertension, a condition in which the systolic (heart-pumping) blood pressure rises to 160 millimeters of mercury (mm Hg) or more, but the diastolic (heart-resting) pressure remains at the normal value of less than 90 mm Hg. Scientists believe people show signs of the condition as they age, perhaps because the blood vessels lose their flexibility, a process that forces the heart to pump harder and thus raises the pressure. Indeed, by age 80, nearly one-quarter of all Americans show an elevated systolic pressure, which is associated with a two-fold greater risk of stroke, as well as an increased threat of heart attack.

Despite that well-documented risk, physicians generally have taken a cautious approach to putting their elderly patients on medications. Many prefer not to treat elevated systolic hypertension, fearing that the risks their patients face in using drugs for the rest of their lives outweigh the benefits. Moreover, previous scientific studies had not shown these antihypertensive drugs could protect people from stroke.

Now researchers at 16 medical centers in the United States report data detailing the stroke-lowering benefits and safety of antihypertensive drugs given to elderly men and women with isolated systolic hypertension.

The team recruited 4,736 volunteers with healthy diastolic pressures but dangerous elevations in systolic pressures that ranged from 160 to 219 mm Hg. Then the investigators randomly assigned people to receive daily doses of placebo pills or an active medication. Neither the researchers nor the volunteers in the "double-blinded" study knew who received the placebo and who got the drugs.

Men and women assigned to the active treatment group received either 12.5 milligrams or 25 milligrams of the diuretic drug chlorthalidone per day. (Diuretics help control blood pressure by ridding the body of excess fluid.) For people who remained hypertensive during this initial therapy, the team added other high blood pressure medications (primarily the beta blocker atenolol) to the daily regimen.

Throughout the trial, people taking antihypertensive drugs averaged an 11 to 14 mm Hg drop in their systolic blood pressure compared with the placebo group. More importantly, the team's five-year analysis revealed 5.2 strokes per 100 people in the active treatment group compared with 8.2 strokes per 100 participants in the placebo group.

That finding represents a "highly significant" 36 percent reduction in the total incidence of stroke, says Jeffrey L. Probstfield, study director at the National Heart, Lung, and Blood Institute in Bethesda, Md. Probstfield coordinated the 16-site trial, called the Systolic Hypertension in the Elderly Program or SHEP. People with artery-pounding pressures can suffer strokes when an artery carrying blood to the brain bursts, he notes.

Drug therapy proved healthy for the heart as well as the brain: Compared with controls, the people in the active treatment group showed a 32 percent reduction in cardiovascular problems, including heart attack.

Most elderly people tolerated the low-dose drug regimen without experiencing dangerous side effects, although 13 percent of the people assigned to the active treatment had to stop taking the drugs because of side effects such as headaches or dizziness, the team reports in the June 26 JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION.

Such findings suggest doctors can safely treat elevated systolic pressures in most elderly patients, including fragile octogenarians, comments geriatric specialist Margaret A. Winker of the University of Chicago Medical Center.

The study also suggests that older people with isolated systolic hypertension can remain healthy, and perhaps boost their longevity, by taking low doses of antihypertensive drugs, Stamler adds.
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Title Annotation:chlorthalidone and other antihypertensive drugs
Author:Fackelmann, Kathy A.
Publication:Science News
Date:Jun 29, 1991
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