Tens of millions more Americans will qualify for a diagnosis of high blood pressure, and will need to change their lifestyles or take medicines for the condition, under new medical guidelines released on Monday.
The guidelines, formulated by the American Heart Association and the American College of Cardiology, sharply lower the threshold for normal blood pressure, in effect moving the goal posts for patients nationwide.
The new criteria, the first official diagnostic revision since 2003, result from growing evidence that blood pressure far lower than once was considered normal reduces the chances of heart attack and stroke, and lowers the risk of death.
New research indicates this is true even among older people for whom intensive treatment had been thought too risky.
Now, high blood pressure, or hypertension, will be defined as 130/80 millimeters of mercury or greater for anyone with a significant risk of heart attack or stroke. By those criteria, nearly half of all American adults, and nearly 80 percent of those aged 65 and older, will need to take steps to reduce their blood pressure.
The number of Americans with high blood pressure, or hypertension, will rise to 103 million from 72 million under the previous standard, according to Dr. Robert M. Carey, professor of medicine at the University of Virginia and co-chair of the committee writing the new guidelines.
The number of men under age 45 with a diagnosis of high blood pressure will triple. The prevalence of high blood pressure among women under age 45 will double.
Only those at highest risk, an additional 4.2 million people, will need drug therapy, said Dr. Carey.
“Those numbers are scary, except we recommend lifestyle changes for the vast majority,” he said.
The previous guidelines defined high blood pressure as 140/90. (The first number describes the pressure on blood vessels when the heart contracts, and the second refers to the pressure as the heart relaxes between beats.)
Even under that relatively more lenient standard, close to half of patients did not meet blood pressure goals, said Dr. Eric Peterson, a professor of medicine at Duke University.
“A lot of it is inertia,” he said. “We accept higher blood pressures way more than we should.”
But few risk factors are as important to health. High blood pressure is second only to smoking as a preventable cause of heart attacks and strokes, and heart disease remains the leading killer of Americans.
“If the guidelines are implemented, they will have a big impact,” said Dr. David Goff, director of the division of cardiovascular sciences at the National Heart, Lung and Blood Institute.
The guidelines suggest starting drug treatment with the aim of getting blood pressure below 130/80 for anyone with at least a 10 percent risk of a heart attack or stroke in the next decade. Simply being age 65 or older qualifies as such a risk if their blood pressure is higher than the new standard.
Younger patients at risk include those with conditions like established heart disease or diabetes. The new standard will apply to them, as well.
People whose risk of heart attack or stroke is less than 10 percent will be told to aim for blood pressure below 140/90, and to take medications if necessary to do so.
If there is any good news for patients here, it is that nearly all the drugs used to treat high blood pressure are generic now. Many cost pennies a day, and most people can take them without incident.