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Why doctors are excited about mobile blood pressure monitoring

In the first decade of this century, deaths attributed to high blood pressure have increased nearly 40 percent – roughly one in three adults in the US now suffer from the condition, according to the U.S. Centers for Disease Control and Prevention. Also called hypertension, high blood pressure has a strong comorbid association with diabetes, meaning if you have one you’re far more likely to have the other. Complications are wide-ranging, including coronary artery disease, myocardial infarction, stroke, congestive heart failure, and peripheral vascular disease. There’s a reason it’s called the “silent killer.”

“We need to get on top of this now,” Dr. Elliott Antman, an associate dean of clinical and translational research at Harvard Medical School and president of the American Heart Association, recently told HealthDay.

An obvious place to start: make sure that blood pressure monitoring, and thus diagnosis, is accurate, but a large new study published in the Annals of Internal Medicine is calling into question whether we’re going about it the best way possible.

In a review of 19,309 abstracts and 1171 articles, researchers from the US Preventive Service Task Force found that “ambulatory” monitors worn during a person’s daily routine were as much as 40 percent more accurate predicting heart attacks, strokes, and heart disease than single checks taken at the doc’s.

There are a few reasons. For one, there is quite simply more data being gathered when a cuff worn around one’s arm checks blood pressure at regular intervals throughout a day. But this kind of mobile monitoring also helps catch two types of people who are easily misdiagnosed – those with “white coat” syndrome, who get nervous in doctor’s offices and experience artificially high blood pressure at precisely the time of monitoring (a condition that may affect as many as 30 percent of people thought to be hypertensive), and those who react oppositely, with lower readings either because they take their meds before going to the doctor’s or because they experience more stress in their home environment.

There are also those who are near the threshold of high blood pressure and difficult to diagnose, as well as those with a single bad test – outliers that can result in unnecessary medicating.

“[Ambulatory monitoring] is going to refine the initial screen performed in a doctor’s office, and give you more accurate results,” said Margaret Piper, a senior investigator at the Kaiser Permanente Center for Health Research and lead author of the review.

If Piper’s task force recommendation to switch to ambulatory monitoring becomes final, health insurers would have to pay for it because preventive procedures that are approved by the task force must be covered under the Affordable Care Act.

Another recent study in the same journal found that blood pressure-lowering drugs help people with even mild hypertension, lending further support to the notion that catching subtleties and getting more accurate readings is important. (In fact, people whose high blood pressure was spotted early and medicated were able to lower their risk of stroke by almost 30 percent, heart-related death by 25 percent, and heart failure by 20 percent.)

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Unfortunately, the ambulatory monitoring recommendation comes at a tricky time – when there are more home monitoring apps than ever, but they appear to be inferior to the ones used in doctor’s offices.

“This technology is really in its nascent stages, and it’s not quite ready for prime time,” Dr. Nilay Kumar, lead author of a new study reviewing 107 apps available on the Google Play store and Apple iTunes, told Reuters Health.

Kumar, who “was surprised” to find that these apps have been downloaded as many as 2.4 million times, added: “It’s not ready for clinical use. For now, we need to be careful that we are not using things that are inaccurate and could be potentially dangerous.”

Piper stressed that the ambulatory devices her task force is recommending are not the same – they still involve wearing an arm cuff as opposed to simply pressing one’s finger on a smartphone screen – while the newest ones can now wirelessly connect to smartphones to easily track the readings. They also take readings at regular intervals, as opposed to whenever a user thinks of it.

“We had data for self-monitoring that seemed to follow the same pattern as ambulatory monitoring, but there were far fewer studies, so we didn’t feel we had enough data to draw conclusions,” she said.

If you’re set on buying your own monitor, the American Heart Association recommends cuff-style upper-arm monitors that has been tested and approved and that fits, while it specifically recommends against finger and wrist monitors. The Dabl Education Trust has compiled a list of validated monitors.

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