ANAHEIM — New guidelines lower the threshold for high blood pressure, adding 30 million Americans to those who have the condition, which now plagues nearly half of U.S. adults.
High pressure, which for decades has been a top reading of at least 140 or a bottom one of 90, drops to 130 over 80 in advice announced Monday by a dozen medical groups.
The change means an additional 14 percent of U.S. adults have the problem, but only 2 percent of these newly added people need medication right away; the rest should try healthier lifestyles, which get much stronger emphasis in the new advice. Poor diets, lack of exercise and other bad habits cause 90 percent of high blood pressure.
"I have no doubt there will be controversy. I'm sure there will be people saying 'We have a hard enough time getting to 140,'" said Dr. Paul Whelton, a Tulane University physician who led the guidelines panel.
But the risk for heart disease, stroke and other problems drops as blood pressure improves, and the new advice "is more honest" about how many people have a problem, he said.
Currently, only half of Americans with high blood pressure have it under control.
The upper threshold for high blood pressure has been 140 since 1993, but a major study two years ago found heart risks were much lower in people who aimed for 120. Canada and Australia lowered their cutoff to that; Europe is still at 140 but is due to revise its guidance next year.
The guidelines were announced Monday at an American Heart Association conference in Anaheim.
WHAT THE CHANGES MEAN
The guidelines set new categories and get rid of "prehypertension":
—Normal: Under 120 over 80
—Elevated: Top number 120-129 and bottom less than 80
—Stage 1: Top of 130-139 or bottom of 80-89
—Stage 2: Top at least 140 or bottom at least 90
That means 46 percent of U.S. adults have high pressure (stages 1 or 2) versus 32 percent under the old levels.
How common it is will roughly triple in men under 45, to 30 percent, and double in women of that age, to 19 percent.
For people over 65, the guidelines undo a controversial tweak made three years ago to relax standards and not start medicines unless the top number was over 150. Now, everyone that old should be treated if the top number is over 130 unless they're too frail or have conditions that make it unwise.
"The evidence with this is so solid, so convincing, that it's hard to argue with the targets," said Dr. Jackson Wright, a guidelines panel member from University Hospitals Cleveland Medical Center. Older people "have a 35-to-50-fold higher risk of dying of a heart attack or stroke compared to younger people."
But the Cleveland Clinic's Dr. Steven Nissen said he's worried.
"Some more vulnerable patients who get treated very aggressively may have trouble with falls" because too-low pressure can make them faint, he said.
WHO NEEDS TREATMENT
Certain groups, such as those with diabetes, should be treated if their top number is over 130, the guidelines say. For the rest, whether to start medication will no longer be based just on the blood pressure numbers. The decision also should consider the overall risk of having a heart problem or stroke in the next 10 years, including factors such as age, gender and cholesterol, using a simple formula to estimate those odds.