Treating Prehypertension Lowers Stroke Risk: Study
THURSDAY Dec. 8, 2011 -- A new study found that the risk of stroke dropped about 22 percent in people with prehypertension who took drugs that lower blood pressure.
These people didn't yet have high blood pressure, but they still benefited from taking the medications, although there was no significant reduction in the rate of heart attacks for people taking antihypertensives.
"We know that blood pressure and stroke are closely related, and high blood pressure is an extremely high risk factor for stroke. If we could reduce blood pressure, we thought we could reduce the risk of stroke," said lead researcher Dr. Ilke Sipahi, an assistant professor of medicine at Case Western Reserve University's Harrington-McLaughlin Heart and Vascular Institute and University Hospitals Case Medical Center in Cleveland.
"We found a highly statistically significant 22 percent risk reduction in stroke with any kind of antihypertensive that was used," said Sipahi.
Results of the meta-analysis were published online Dec. 8 and are scheduled to appear in the February 2012 print issue of Stroke.
Prehypertension is defined as blood pressure that is between 120 to 139 mm Hg systolic (the top number) and 80 to 89 mm Hg diastolic, according to background information in the study. Anything 140/90 mm Hg and above is considered hypertension. Prehypertension is very common, and may affect as many as 40 percent of Americans, according to the study.
Not everyone with prehypertension will go on to develop high blood pressure, but many will. And, according to the study, prehypertension alone increases the risk of stroke and heart attack.
However, there are no current guidelines that recommend drug treatment for prehypertension. The current treatment is lifestyle changes, such as quitting smoking, losing weight and getting regular physical activity. Sipahi said that lifestyle changes can be effective when they're implemented consistently.
The current meta-analysis looked at the effect that blood pressure-lowering medications might have on the risk of stroke, heart attack and cardiovascular death.
The researchers found 16 randomized controlled trials involving people with prehypertension taking a form of blood pressure-lowering drug, such as an ACE inhibitor, beta blocker or angiotensin receptor blocker. These studies had a total of nearly 71,000 people enrolled in them.
For people receiving active treatment with an antihypertensive, the risk of stroke dropped by 22 percent.
The researchers also found that to prevent one stroke from occurring, 169 people would have to be treated with a blood pressure medication for an average of 4.3 years.
The risk of heart attack wasn't reduced, but the researcher said there was a trend toward fewer cardiovascular deaths, though the trend didn't reach statistical significance.
"Now that we know the risk of stroke can be reduced, perhaps we need to do risk stratification. If you're someone at particularly high risk, maybe we should pull the trigger on treatment earlier, and not necessarily wait until they reach that magic number of 140/90," Sipahi said. He said that lifestyle changes should be tried first. If those changes fail, then it might be time to consider medication to lower blood pressure, he said.
"This is a big study that adds to the argument of shifting to earlier intervention. When to initiate treatment for something that is 'pre' disease is challenging, and more studies are needed," said Dr. Robert Graham, an internist at Lenox Hill Hospital in New York City.
"I'd still recommend that people work on known risk factors. Don't give up on lifestyle changes," he added.
Learn more about high blood pressure and prehypertension from the U.S. National Heart, Lung, and Blood Institute.
Posted: December 2011