WASHINGTON - Some 45 million Americans with blood pressure levels once considered normal or borderline actually have "prehypertension," say new government guidelines that urge them to exercise, avoid salt and make other changes to stave off full-blown high blood pressure.
It's a major change 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.
Scientists now say that damage to arteries from the pressure of blood pounding through them begins to increase at levels as low as 115 over 75. Even a small jump from that low - to 130 over 85, a level previously considered in the normal range - means a doubling of the risk of later death from heart disease, say the guidelines by the National Heart, Lung and Blood Institute.
Hence the new emphasis on at least delaying the gradual rise in blood pressure that so many Americans see with age. Still, the report promises to be a shock for people told for years their blood pressure was healthy, only to learn they're now considered "prehypertensive" unless their level is below 120 over 80.
"We don't want to frighten the public, we want to get action," said Dr. Aram Chobanian, dean of Boston University's medical school who chaired the government-appointed committee that drafted the guidelines. "Even small changes in blood pressure are important."
Other recommendations in the broad report, published in a special online edition of the Journal of the American Medical Association on Wednesday, are generating controversy, as doctors debate just which medication is best once hypertension hits.
The guidelines say most people who already have high blood pressure will need at least two medications to control the dangerous disorder - and most should at least try a cheap, old-fashioned diuretic as initial therapy.
At a major meeting of hypertension experts, doctors argued Wednesday that that was the wrong advice for many people.
"They haven't justified those steps," said Dr. John Laragh of New York Hospital/Cornell University Medical Center, who contends only 35 percent of people with hypertension have the type that responds to diuretics. Many of the rest, he said, could do fine with one other drug, such as an ACE inhibitor or beta blocker.
The authors responded that the guidelines say diuretics aren't the only option - and that patients with additional diseases, such as heart-attack survivors, may do better with other medications.
"Nobody's advocating some kind of cookbook medicine," said Dr. Claude Lenfant, director of the federal heart institute.
The guidelines also say that:
- Blood pressure is measured as two values and the first number, the systolic pressure, is the most important for anyone over 50 - something too few doctors and patients understand. If nothing else, that number should be below 140.
- Doctors should be far more aggressive in treating hypertension. Almost a third of people with high blood pressure don't know it and two-thirds of the diagnosed don't have the disease under control - too often because doctors hesitate to prescribe a second or third medication, said co-author Dr. Daniel W. Jones of the American Heart Association.
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.
They 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 factors that increase blood pressure, the guidelines say.
"We hope it's going to catch people's attention," Jones said of the new prehypertension category. "They are at higher risk for going on to develop hypertension and they need to take action."