In the U.S., the state of blood pressure monitoring is changing. Recommendations published in February by the U.S. Preventive Services Task Force suggest the use of 24-hour ambulatory, home or automated blood pressure monitoring instead of conventional office measurements for the diagnosis of hypertension. This should allow physicians to better separate the wheat from the chaff: true hypertension from what’s known as white coat or masked hypertension.
One in three Americans has high blood pressure (Ann Intern Med 2015; 162:192-204). An estimated 20 to 35 percent of patients who register with high or hypertensive blood pressure in the office may be reacting instead to how the test is performed, the professional giving the test or to the office setting in general (Curr Cardiol Rep 2015; 17:2). In addition, human errors can be made when taking measurements. Blood pressure cuffs can be deflated too quickly. A physician or nurse may be less likely to hear the breaking points when he or she or a patient talks. Numbers can be rounded. Too much time might pass between multiple visits to accurately see trends.
This has led to a movement away from traditional auscultatory measurements by clinicians and professional groups globally. But, the question remains: How best to diagnose high blood pressure?
“There is a lot of debate in the literature,” says Lyne Cloutier, RN, PhD, professor with the University of Quebec at Trois-Rivières. She and her colleagues developed an algorithm to diagnose hypertension in Canada. “Which one is best, home or ABPM (ambulatory blood pressure monitoring)?”
The long view
Cloutier’s team considers ambulatory to be the best choice to allow physicians to separate true hypertension from white-coat syndrome. “ABPM certainly has the net advantage in that it gives us night measurements,” she says. Providing a physician with an average of 70 readings over a 24-hour span, it allows physicians to see daily trends.
Cloutier’s group emphasizes that outside-of-office blood pressure measurements are necessary between the first and second visit. This does not preclude the use of other methods, she says. In some areas, ambulatory blood pressure monitoring may not be available. Some patients, like those who are obese, may not easily use ABPM cuffs as currently designed. This is why, while 24-hour monitoring may be what she and her team noted as the preferred option, the algorithm does allow for other methods.
“[ABPM] is really a great tool but home blood pressure is not far behind,” she says. “When ABPM is not tolerated we certainly want to get the patient involved. And patients want to get involved.”
As an alternative, home blood pressure monitoring provides some advantages. While it doesn’t take readings overnight or when a patient is away from home, it does allow the patient to have blood pressure taken in a more comfortable, familiar setting. It gets patients involved in their own care which in turn has its own rewards.
“There’s some evidence that if people have the device at home they will improve their blood pressure level,” says Alejandro Arrieta, PhD, an assistant professor at Florida International University in Miami who conducts economic analyses of various approaches. “They’ll probably adhere better to their medication. From different channels they will control their hypertension better.”
Arrieta supports the use of home blood pressure monitoring. He and his team looked at the costs of using home blood pressure monitoring from an insurer’s perspective. In his analysis, “It makes decent sense to a payer to reimburse for home blood pressure monitoring [because] the return on investment is positive.”
However, with the rate of turnover experienced by U.S. insurers, Arrieta adds, “It’s very difficult to think that in a model like the U.S. that ambulatory blood pressure monitoring could be adopted—at least not now for the high price. We think that home blood pressure monitoring is the most feasible.”
Home monitoring is subject to some of the same pitfalls found in taking manual readings in the office, notes Martin G. Myers, MD, professor at the University of Toronto and a cardiologist at Sunnybrook Health Sciences, also in Toronto. By making the patient responsible for pushing a button three times to start readings, he says, patients’ registered measurement can rise a little bit.
He also notes that patients can misread or falsely report blood pressure findings. For accuracy, he recommends whatever device used be automated. He says leaving a patient in an exam or waiting room alone “anywhere without talking to them, just undisturbed and have a device that takes several readings, between three and five readings say every minute over four or five minutes, you get a better estimate of their blood pressure status than if a human being is taking it.”
Decisions to make
Whichever method, improving diagnosis is important. Myers notes that for the U.S., this means using validated automated devices. “The U.S. is dated behind Europe and Canada, Australia and Japan in adopting automated technology and risk measurements devices,” he says. “In Canada about one-third of primary care physicians are using this method before it was recommended. I’m sure that next year’s guidelines are going [toward] measurements without anybody in the room.”
Training and accurate devices also make a difference, says Cloutier. “We could treat [patients] better and save them from cardiovascular events or even death. We believe that by using an algorithm where we encompass or take into account ABPM will do patients good.”