One-fifth of Canadians diagnosed with hypertension don’t actually have it: study

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About 20 per cent of people being treated for high blood pressure don't have it, researchers say – Mar 20, 2017

More than half of family doctors in Canada use outdated methods to measure blood pressure and it’s leading to a misdiagnoses in a number of patients, a Canadian study found.

According to researchers at the University of Montreal Hospital Research Centre (CRCHUM), about 20 per cent of people getting treatment for hypertension don’t actually have it, and it’s mainly due to improperly measured blood pressure with older instruments.

“This study is a culmination of research that has been done in Canada throughout the years and it has to do with improving the way that blood pressure is measured in routine clinical practices,” says Dr. Janusz Kaczorowski, lead author of the study. “[In our study] it became quite apparent that manual — or traditional — ways of measuring blood pressure is probably not the best option for Canadian patients.”
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READ MORE: ‘Masked’ hypertension: You may have high blood pressure and not even know, docs warn

In 2016, Kaczorowski’s team conducted a survey among 769 Canadian family physicians. They discovered that 52 per cent of physicians are still using a manual tensiometer to measure patients’ blood pressure instead of the automatic device, which has been the recommended method in the Canadian Hypertension Education Program (CHEP) Guidelines since 2016.

Kaczorowski acknowledges that while the new automatic electronic measuring devices (called oscillometric devices) are expensive, they’re more precise and consistent in their measurements. He also says that manual measurement is acceptable if it’s done properly, but it’s often not the case.

In fact, automated devices eliminate something called white-coat syndrome, an artificially high blood pressure often caused by the stress of being in doctor’s offices and human interaction.

There may be a number of reasons why more physicians haven’t transitioned over to the automated device – among them being the cost and awareness.

To do proper blood pressure, it must be measured in a 12 to 15 minute window. However, most visits don’t last that long, Kaczorowski says, thus resulting in misleading results.

“A lot of people were taught in medical school how to measure blood pressure using a stethoscope and the manual approach and that’s what they’ve always been doing so they are comfortable with the technique,” Kaczorowski says. “It’s one of those situations where everybody believes that the way that they are measuring is accurate and valid and it’s everybody else who has a problem.”

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And when a misdiagnoses of hypertension occurs, there is potential for harm to the patient, Kaczorowski points out.

READ MORE: Reality check: Does eating potatoes four times a week really put you at risk of hypertension?

One study done by researchers at New York University’s School of Medicine in 2008 concluded that white-coat hypertension was an important clinical problem that may lead to inappropriate drug treatments.

According to a 2015 University of Calgary study, healthcare costs associated with hypertension were pegged at $13.9 billion in 2010 and is projected to rise to $20.5 billion by 2020.

Should a patient notice their physician isn’t using an automated device and is concerned with accurate tracking, Kaczorowski suggests to monitor one’s own blood pressure at home using an at-home machine.

“Hypertension is a silent killer,” Kaczorowski says. “So now we really want doctors to really start improving their technique and monitoring blood pressure, as well as using automated devices to monitor their patients. I think that would greatly enhance the quality for both diagnosis and the subsequent treatment that Canadian patients receive from their patients.”

Almost 18 per cent of Canadians 12 years of age and older (5.3 million people) reported being diagnosed with high blood pressure, a 2014 Statistics Canada report says. The number of reported cases has been steadily increasing since 2001, when almost 13 per cent of Canadians reported a hypertension diagnosis.

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