One in three or 29 percent of Americans currently have high blood pressure. Unchecked, this condition can lead to heart disease, stroke and kidney disease. But is high blood pressure so prevalent because it’s over diagnosed? A new study says yes.
But how does this happen?
“Blood pressure is often determined using the wrong techniques under the wrong circumstances,” explains Scott Renshaw, MD, physician at Indiana University Health. “For instance, blood pressure might be taken immediately when a patient is put in the exam room, but for an accurate reading one should wait at least five minutes first.”
Dr. Renshaw explains that patients need to sit quietly for at least five minutes, feet flat on the floor, before blood pressure is taken. But because doctors’ schedules are so rushed, patients’ blood pressure often is taken more quickly than is recommended. Another problem is that people often are nervous and anxious in doctor’s offices, which can cause falsely high blood pressure readings; doctors call this phenomenon “White Coat Syndrome.” Putting the wrong size arm cuff on a patient is another common mistake, Dr. Renshaw adds.
All in all, the study authors concluded that 20 percent of the people they studied who were being treated for hypertension didn’t actually have a problem. One potential reason for the misdiagnoses? The study authors stated that about half of the doctors used manual blood pressure measurements, which are thought to be less accurate than automated blood pressure machines.
Dr. Renshaw disagrees: The accuracy of digital measurement tools depend on how well machines are maintained and calibrated, he says. So many doctors still stand by the old-school manual method as the best way to get accurate blood pressure readings.
Other experts agree: “Measuring blood pressure manually is the most accurate way, but you have to do it well,” says Dr. Elisabeth von der Lohe, MD, a cardiologist at Indiana University Health.
Training patients how to take their own blood pressure at home can also give physicians a much more accurate picture, she says. “I have my patients take their own blood pressures at home three times a day and call in with their numbers every two to three weeks,” Dr. von der Lohe says. “That’s much more accurate than taking blood pressure one time in my office.”
Although many patients can learn how to take their own blood pressure with an arm cuff, it can be difficult for seniors, Dr. von der Lohe says, who might have trouble adjusting the cuff correctly or might not have good enough hearing to pick up the heart beats via stethoscope. It’s easier for them to put on a wrist cuff and push a button, she says.
The good news: many at-home blood pressure monitors are capable of rendering accurate readings, as long as you take the proper steps to get them, such as sitting quietly for 10 minutes with your feet flat on the floor and with your arm at the level of your heart, Dr. von der Lohe says. And some of the most basic wrist cuff devices are actually the most accurate, she adds.
Still, this study highlights the difficulty in diagnosing hypertension, and Dr. von der Lohe agrees that it’s difficult to diagnose well. Taking medication for hypertension when you don’t need it can cause blood pressure to drop to dangerously low levels, which could make a person dizzy and even lead to stroke, she says
That said, both experts agree that frequent at-home blood pressure monitoring, in conjunction with checks at the doctor’s office, is the best way to make sure hypertension is properly treated.
-- By Virginia Pelley