Jan. 5, 2000 (Atlanta) -- Risk of death from heart disease is high for people whose blood pressure goes up -- even people not usually thought to be at risk. The finding, published in this week's The New England Journal of Medicine, comes from a 25-year, seven-country study showing that, at all blood-pressure levels, small increases in blood pressure greatly increase the risk that a person will die of heart disease.
In an editorial accompanying the study, Stephen MacMahon, PhD, MPH, says the study findings mean that there should be major changes in the way doctors manage blood-pressure-related diseases such as stroke and heart failure. The biggest change, he argues, is that people with high blood pressure -- a condition known as hypertension -- are far from the only people at risk of dying.
"These data from the 'Seven Countries' study now indicate without a shadow of a doubt that an individual's level of blood pressure is a major indicator of his or her risk of coronary heart disease," MacMahon, of the University of Sydney, Australia, tells WebMD. "It's not just hypertensive people, but the whole community."
The study regularly measured the blood pressure of more than 12,000 men 40-59 years old. The men were grouped into six populations: the U.S., northern Europe, Mediterranean southern Europe, inland southern Europe, rural Serbia, and Japan. None of the men had heart problems at the beginning of the study, but during the 25-year study nearly 1,300 died of heart disease.
At the same level of blood pressure, Peggy C.W. van den Hoogen, MSc, and co-workers found, U.S. and northern European men were more than three times as likely to die of heart disease as men in Japan and Mediterranean southern Europe. But when the researchers examined the effect of small increases in blood pressure, they found the same 28% increased risk of death for all populations.
"We found there is a large difference in the risk of death from coronary heart disease between men in different parts of the world," van den Hoogen tells WebMD. "Independent of baseline [that is, the beginning] blood pressure level, a given increase in blood-pressure level means a certain increase of risk."
MacMahon notes that small changes in blood pressure across an entire population -- such as those that could be achieved by reducing salt or calorie intake -- would save a very large number of lives.
Laurence Sperling, MD, FACC, FACP, director of preventive cardiology at Emory University Medical Center in Atlanta, agrees. "To me, it's not a surprise that a small difference in blood pressure can make a big difference in risk of cardiovascular disease," Sperling tells WebMD in an interview to provide objective comment. "A lot of people have felt, 'If my blood pressure is not super-high, I'm not at risk of stroke today.' But we know there is a cumulative effect of walking around with high blood pressure for a long time. We should work toward optimal blood pressure. Optimizing blood pressure is a difficult thing to achieve. It takes a lot of hard work and diligence on the part of both physician and patient. It is something everyone has to work at very hard."
MacMahon stresses the need to recognize that blood-pressure-related disease affects many more people than previously thought. "Lifestyle changes should be considered across the board for individuals at risk," he says. In regard to medications, he states that most blood pressure-lowering drugs are still limited to those with diagnosed hypertension. More clinical trials are needed to investigate the use of blood-pressure lowering drugs on others at risk for blood-pressure-related diseases.
Such studies should begin as soon as possible, MacMahon argues. He notes that single-drug treatment with most available agents lowers blood pressure by only 5-10%. Although drug combinations or new drugs can increase this action by about half, new drugs urgently are needed.
"There is the potential to avoid millions of unnecessary deaths, heart attacks, and strokes each year by the development of more effective treatments for blood-pressure reduction," he says.
- Small increases in blood pressure raise the risk of death from coronary heart disease, even in those who are not diagnosed with high blood pressure.
- To lower blood pressure, experts advise medical treatment, sodium restriction, weight loss, and limited alcohol consumption.
- Blood pressure medications are currently approved only for those who have diagnosed high blood pressure, but further study is needed for others who are at risk for blood pressure-related diseases.