Revised Blood Pressure Guidelines Put Millions in New Category

For years, Americans with blood pressure readings below 140 over 90 typically considered their levels safely in the normal range; so did their physicians. Then in mid-May the National Heart, Lung, and Blood Institute (NHLBI) issued revised guidelines, including a new "prehypertension" category affecting about 22% of American adults – that’s about 45 million of us. Under the new guidelines, readings are regarded as normal and optimal only if they are lower than 120 over 80. Blood pressures of 120-139 over 80-89 are considered prehypertensive.

“This is important,” says Theodore A. Kotchen, MD, Professor of Medicine in the Department of Endocrinology, Metabolism and Clinical Nutrition at the Medical College of Wisconsin. “It alerts people in the prehypertensive range that they are at increased risk of developing cardiovascular disease,” he says, “and the report recommends they institute modifications in their lifestyles, including diets, to lower their blood pressure levels.”

Dr. Kotchen was one of the physician-researchers invited to review the new guidelines before they were published, and he has been involved in writing earlier guidelines released by NHLBI’s Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.

Dr. Kotchen, who also is Associate Dean for Clinical Research at the Medical College, is the co-author of an article in the July 9, 2003, issue of the Journal of the American Medical Association (JAMA) titled “Trends in Prevalence, Awareness, Treatment, and Control of Hypertension in the United States, 1988-2000.” The study was based on research done here at the Medical College and at the University of South Carolina. Researchers found that the prevalence of hypertension (also called high blood pressure) had increased in the United States during the 1990s, due in part to a tremendous rise in the incidence of obesity in the country.

Serious Consequences
According to NHLBI – which is part of the National Institutes of Health – high blood pressure increases the risk of people developing stroke, heart attack and heart failure, as well as kidney disease. It is especially dangerous because it often has no warning signs or symptoms.

Blood pressure is the force of blood pushing against the walls of arteries – the blood vessels that carry blood away from the heart to other parts of the body. Blood pressure can rise and fall depending on a person’s general health, their level of physical activity, the time of day and many other factors. High blood pressure, or hypertension, is dangerous because it makes the heart work too hard and contributes to atherosclerosis (hardening of the arteries).

The upper number in a blood pressure reading is called the systolic blood pressure, which measures the force of blood in the arteries as the heart beats. A systolic reading of between 120 and 139 is now regarded as prehypertensive; a reading of 140 or more is considered high. The lower number measures diastolic pressure, or the force of blood in the arteries as the heart relaxes between beats. Diastolic pressure ranging from 80 to 89 is now classified as prehypertensive, and a reading above 90 is considered high. Both numbers are important, but for people who are 50 or older, systolic pressure is a stronger predictor of hypertension-related complications.

Diet, Exercise Can Prevent Damage
What should you do if you’re suddenly in the new prehypertensive category? In a phrase, start shaping up now, the NHLBI report says. The JAMA article by Dr. Kotchen has the same advice: “Programs targeting hypertension prevention and treatment are of utmost importance,” it concludes.

“The new report recommends people adopt a healthy diet that is high in fruits and vegetables, fiber and low-fat dairy products,” Dr. Kotchen says. “They should limit their intake of salt and other sodium, lose weight if they are overweight, reduce alcohol consumption and increase their physical activity.”

For most people classified as prehypertensive, these measures alone could lower their blood pressure readings to normal levels. If that’s not possible, they will become part of the 29% of Americans (about 58 million people) living with high blood pressure, and they will require daily medications to control their disease.

The new guidelines also streamline the steps by which doctors diagnose and treat patients. It recommends the use of diuretics (often called “water pills”) as part of the drug treatment plan for high blood pressure in most patients, either alone or in combination with another drug class. The report notes that even though many studies have found diuretics to be effective in preventing hypertension's cardiovascular complications, they are currently not being sufficiently used.

Getting the right combination of medications for individual patients can be a matter of trial and error, Dr. Kotchen says, adding: “Most primary-care physicians are perfectly capable of managing most cases of hypertension.” A small percentage of patients have hypertension that is difficult to control, and they might be referred to a specialist such as a nephrologist (kidney specialist), cardiologist (heart specialist) or endocrinologist, who specializes in glands and hormones.

Prehypertensive patients with complicating factors such as diabetes or kidney disease are encouraged to keep their blood pressure levels even lower than those recommended for the general population.

Children Can Have Hypertension, Too
Although the incidence of hypertension increases as we age, it’s beginning to appear in younger and younger patients, reflecting the rise in obesity among Americans. “We’re seeing more children and adolescents with Type 2 diabetes and elevated blood pressure,” Dr. Kotchen says.

In addition, there is evidence that hypertension runs in families. Dr. Kotchen and his colleagues at the Medical College are conducting research on both people and animals to identify specific genes that may predispose certain individuals to high blood pressure. The study reported in JAMA notes that 30% of Americans with hypertension were not aware of their condition. Of the remaining 70%, more than half (42%) were not being treated for it, and 70% did not have their hypertension under control.

“Have your blood pressure checked every time you visit your doctor,” Dr. Kotchen advises. If it’s in the new prehypertensive category, take that as a warning to start exercising more and eating a more healthful diet. And if it’s too high, expect to take daily medication to prevent serious complications.

Barbara Abel
HealthLink Contributing Writer

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.