WASHINGTON (AP) - Millions of people who thought they had healthy blood pressure are about to get a surprise: The government says levels once considered normal or borderline actually signal "prehypertension," and those people must take care to stave off full-blown high blood pressure.
It's a major change, in new federal guidelines being released Wednesday, that affects people with blood pressure as low as 120 over 80 - once thought to be a good level but now considered not good enough.
About 45 million Americans are in this prehypertensive range, says the National Heart, Lung and Blood Institute, which issued the new recommendations. The change comes from recent scientific studies showing the risk of heart disease begins at blood pressures lower than previously thought.
Also in the guidelines:
-Most people who already have high blood pressure will need at least two medications to control the dangerous disorder.
-For the majority of patients, one of those drugs should be a cheap, old-fashioned diuretic.
-Blood pressure is measured as two values and the first, or top, number in the reading is the most important for anyone over age 50 - something too few doctors and patients understand. If nothing else, that number should be below 140.
The guidelines overall urge doctors to be far more aggressive in treating hypertension, noting that almost a third of people with high blood pressure don't even know it. Plus, two-thirds of diagnosed patients don't have the disease under control - too often because doctors hesitate to prescribe a second or third medication, said Dr. Daniel W. Jones of the American Heart Association, a co-author of the guidelines.
An estimated 50 million Americans have high blood pressure, often called the silent killer because it may not cause symptoms until the patient has suffered damage. It raises the risk of heart attacks, strokes, heart failure, kidney damage, blindness and dementia.
High blood pressure measures 140 over 90 or more. That level hasn't changed.
Until now, optimal blood pressure was considered 120 over 80 or lower; normal was up to 130 over 85; and levels above that were called borderline until patients reached the hypertension range.
But the new guidelines classify normal blood pressure as below 120 over 80 - and readings anywhere from 120 over 80 up to 140 over 90 as prehypertensive.
"We hope it's going to catch people's attention," Jones said of the new prehypertension category. "This is not to alarm people but simply deliver the message that ... they are at higher risk for going on to develop hypertension and they need to take action."
That doesn't mean medication. Instead, people with prehypertension should lose weight if they're overweight, get regular physical activity, avoid a salty diet and consume no more than two alcoholic drinks a day. All those factors increase blood pressure, the guidelines say.
Recent scientific studies show that risk of heart disease actually begins rising once blood pressure creeps above 115 over 75, said guideline co-author Ed Roccella, a hypertension specialist at the heart institute.
There's a doubling of risk for each 20-point rise in the top number, called the systolic pressure, or 10-point rise in the bottom number, the diastolic pressure.
"Most of us will have hypertension if we live long enough," said Roccella. The hope is that if people know they're prehypertensive - even if they're a skinny 20-something with 120 over 80 readings today - they'll make wiser lifestyle choices and thus stave off the blood-pressure creep that comes with age.
The guidelines will be published in next week's Journal of the American Medical Association, but because of their importance are being released early online Wednesday.
On the Net:
Federal hypertension info: http://www.nhlbi.nih.gov/hbp