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Taking Blood Pressure at Home Makes Sense

Combining it with office readings gives best picture of hypertension risk

TUESDAY, Feb 24, 2004 (HealthDayNews) -- Monitoring blood pressure at home can save money and give doctors valuable insight into a patient's hypertension risk, a new study says.

The researchers note that mixing readings at home and at the doctor's office can spot true cases of high blood pressure.

"Don't base this treatment on one blood pressure reading in the office, because people are living the rest of the day -- the other 23 hours and 45 minutes -- and they've obviously still got a blood pressure. It's important to know the average blood pressure over time," explains Dr. Dennis Goodman, chief of cardiology at Scripps Memorial Hospital in La Jolla, Calif.

Sales of in-home portable blood pressure monitors have increased dramatically as patients play a greater role in their own health care. But few studies have examined whether self-monitoring actually saves money or improves patient care.

In their study, a research team led by Dr. Jan A. Staessen of the University of Leuven in Belgium divided 400 hypertensive patients into two groups. Half of the patients received blood pressure readings during regularly scheduled visits to their doctors, while the other half measured their blood pressure on a daily basis at home. One physician, blinded as to whether blood pressure readings were taken in the office or home, then made all decisions as to each patient's treatment over a six-month period. The study appears in the Feb. 25 issue of the Journal of the American Medical Association.

According to the researchers, health-care costs for patients in the home-monitoring group were slightly lower -- just under $5 per month less per patient on average when compared to those tested in doctors' offices. Most of these savings were the result of home monitoring spotting patients with what's known as "white-coat hypertension."

"White-coat hypertension is the transient rise in a patient's blood pressure caused by stress in a medical environment, such as when his or her blood pressure is being measured by a doctor or nurse," Staessen explains. In the absence of outside readings, white-coat hypertension can easily lead to a misdiagnosis of chronic high blood pressure.

The problem is not a small one: Staessen estimates that about "30 percent of hypertensive patients have this condition." Measuring blood pressure in the more relaxed environment of the home can produce lower readings and spare some patients misdiagnosis and unnecessary, expensive drug therapy.

However, the study found that relying solely on home monitoring might not be a good idea, either. Patients in the home monitoring group had less long-term therapeutic control over their blood pressure than patients tested in the clinical environment, the researchers found.

Commenting on the study, Goodman says part of the problem is that what's "normal" in an office-based reading may not be normal at home, because of the influence of white-coat hypertension.

"All of these studies that we do that show a benefit with drug therapy are based on blood pressure measurements in the office," he says. "We really don't have studies based on what blood pressure is doing at home. So what is a normal blood pressure at home?"

Both Goodman and Staessen agree that more studies need to be done to help doctors make better treatment decisions.

The dubious quality of many home-monitoring kits is also troubling to experts. "The public is a victim to the lack of regulation in this field," Staessen says. "Most devices for blood pressure self-measurement are being sold without adequate instructions, [and] have not been properly validated according to current standards."

Goodman agrees. In fact, he asks his patients bring their monitors to his office for testing before he approves them for in-home use. "The first thing I do is tell them to go buy it, and tell the pharmacist or whoever you're buying it from that 'I'm taking this to my doctor, because I want him to verify that it's accurate. If not, I'm bringing it back.'"

Many of the devices prove inaccurate, especially those that measure blood pressure on either the finger or the wrist. "I've seen some of them that come in, they are 30 points different from what I get," Goodman says. "This is not the time you want to get a cheap machine." He advises patients to stick to standard upper-arm monitors and to always take their pressure on the same arm in the same position each day.

Once he's satisfied with his patients' choice of monitor, Goodman will instruct them on its proper use and give them a personal schedule for taking at-home readings. "What's so helpful about home monitoring is that patients get to see that it's not just what you're doing in the office, they can take it themselves," he says. "The more blood pressure readings you can get over the course of a day, the better."

According to the American Heart Association, 50 million American adults now suffer from high blood pressure, a risk factor for heart attack and stroke. Expert guidelines released last year define normal, healthy blood pressure as at or below 120 over 80 (millimeters of mercury). Readings between 120 and 139 (systolic, or the upper figure) and 80 to 89 (diastolic, or the lower figure) are considered pre-hypertensive. Readings of 140 over 90 and above point to high blood pressure, which may require changes in diet, exercise and stress-management, as well as drug therapy if deemed necessary.

In a second study appearing in the same journal, researchers at the Technical University in Munich, Germany, conclude that less may be more when it comes to providing lifesaving drugs to patients with heart attack. In heart attack, restoring blood flow to the damaged heart is key to recovery and long-term survival.

One drug, abciximab (brand name ReoPro), has been shown to help reduce heart attack damage, and is especially crucial when patients don't have immediate access to surgical interventions such as artery-opening angioplasty. In their study, the German team compared the six-month survival of 235 heart attack patients given either abciximab alone or abciximab plus another powerful drug, reteplase, as they underwent emergency care.

They found no significant differences in either the amount of damage to the heart or six-month survival whether patients received abciximab or the combo therapy. In fact, reteplase-abciximab given together appeared to raise risks for bleeding compared to abciximab alone. Commenting on the study, Dr. A. Michael Lincoff of the Cleveland Clinic concludes that "abciximab alone is at least as effective, with less bleeding risk, than the combination [therapy]."

More information

Learn more about blood pressure and how to keep it under control from the Illinois Department of Public Health or the National Heart, Lung, and Blood Institute.

SOURCES: Jan A. Staessen, M.D., Ph.D., cardiologist, University of Leuven, Leuven, Belgium; Dennis Goodman, M.D., chief, cardiology, Scripps Memorial Hospital, La Jolla, Calif.; Feb. 25, 2004, Journal of the American Medical Association
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