Nearly half of adults in the United States have high blood pressure—and many don’t have their hypertension under control. But when patients measure their blood pressure regularly at home, and share those measurements with their doctors, they are playing an important role in their care.
The AMA’s What Doctors Wish Patients Knew™ series gives physicians a platform to share what they want patients to understand about today’s health care headlines and how to take charge of their health through preventive care.
In this installment, two physicians took time to discuss what patients need to know about taking their own blood pressure measurements outside of the clinical setting, also commonly referred to as self-measured BP (SMBP). They are:
- Kenny Cole, MD, MHCDS an internist in New Orleans, medical director for Ochsner Digital Medicine and system vice president of clinical improvement for Ochsner Health.
- Michael Rakotz, MD, a family physician and group vice president of health outcomes at the AMA.
Ochsner Health is part of the AMA Health System Member Program, which provides enterprise solutions to equip leadership, physicians and care teams with resources to help drive the future of medicine.
It’s measuring your blood pressure at home
“Home BP monitoring has also been called ambulatory blood pressure monitoring. It’s essentially monitoring blood pressure from the comfort of your own home where you can do it more regularly with greater frequency,” Dr. Cole said. “It’s less sporadic than getting your blood pressure checked only when you go to a doctor’s office.”
“Having the ability to monitor blood pressure at home on more regular intervals and with higher frequency gets you a more accurate picture of how your blood pressure is doing,” he said. "The more readings you have, the greater accuracy you’re going to have in terms of what is significant from a cardiovascular standpoint.”
At-home BP identifies white coat hypertension
“White coat hypertension happens when someone’s blood pressure is elevated in the office, but it’s normal at home,” said Dr. Cole. “That’s why Home BP monitoring allows for a more accurate representation of what a person’s blood pressure is truly doing.”
“Interestingly, you may have heard of white coat hypertension, but you may not have heard of masked hypertension. Masked hypertension is the opposite,” he said. “It’s when your blood pressure is normal in a doctor’s office and yet you get readings at home and they’re elevated."
“That one is probably even more significant because you get lulled into a sense of complacency if blood pressure is normal every time you go to the doctor’s office--when the reality, is it’s high at home,” Dr. Cole explained. “That is associated with higher cardiovascular risk.”
Who should measure BP at home
“It’s so important to partner with patients on improving their blood pressure,” said Dr. Rakotz. “Having patients take their own BP measurements is a way to do that and engage patients in self-management of their blood pressure.”
“Anyone who already has a diagnosis of high blood pressure can use SMBP to track their BP over time,” he said. “The measurements can help physicians assess the effectiveness of treatments being used.”
Expanding on that, Dr. Cole says at-home blood pressure monitoring is for “anybody who has had an elevated blood pressure reading, especially if there has been more than one in the past--because these are individuals who very well could have high blood pressure.”
This includes people, for example, who have white coat hypertension.
"The only way we’re going to know if it is truly white coat hypertension is to get those ambulatory readings from home,” he said, noting those are the ones that correlate with long-term outcomes.
“If a patient doesn’t have a diagnosis of high blood pressure, home measurements can be used to make an accurate diagnosis,” Dr. Rakotz said. “But it’s also important to understand that if a patient does have high blood pressure, taking home measurements alone is not an effective form of treatment.
“SMBP is something that can be used by a physician and care team to make sure that the treatment plan a patient is following is working and should be accompanied by clinical support,” he added.
Taking your blood pressure at home is important
“It’s important because they call it the silent killer for a reason. There are chronic conditions that a person can have and be completely unaware of, and hypertension is one of those,” said Dr. Cole. “It’s a bit of a myth to think that the only time you can feel your pressure is high is because you have a headache or something like that.
“The answer is, ‘No.’ Your pressure can be high, and you can be thoroughly and completely asymptomatic. That’s one of the reasons why they call it the silent killer because you can be unaware of it,” he added. “It is better to have those multiple readings, especially at home, that actually tell you if it is really controlled or not.”
“If it’s not, it’s important to get that blood pressure as tightly controlled as possible,” Dr. Cole said. “It is just so incredibly important to get an accurate diagnosis and readings that correlate with the ability to manage your blood pressure in such a way that you’re decreasing the risk of things like heart attack, stroke and chronic kidney disease.”
Not all BP measurement devices are equal
“In terms of how accurate the blood pressure monitors at home are, there is some variability there,” Dr. Cole said. “What I would advise people to do is to make sure they have an FDA-approved or validated blood pressure cuff. When I say validated, I mean that scientific evidence has validated that it’s accurate.”
“There’s one place that they can go to get the list of validated blood pressure devices, and that’s targetBP.org https://www.validatebp.org/,” he said. “You can go to the website to check and see if your individual blood pressure monitor is a validated monitor.”
“Make sure that a home BP measurement device has been validated for clinical accuracy, which means it has been tested to make sure that it will give accurate measurements,” said Dr. Rakotz. Patients “can either look at a validated device list or they can ask their doctor for a recommendation.”
“At Ochsner, we have our digital medicine programs where the wireless blood pressure cuffs that we use are FDA approved,” Dr. Cole said. “The beauty of what we do is that not only do our patients get a device, but they wirelessly send their reading into the cloud.
“Then from the cloud it goes into our electronic medical records so that we have a list of all their blood pressures over time that helps us manage that condition,” he added.
Also, patients can use the US Blood Pressure Validated Device Listing™ to find blood pressure measurement devices that have been validated for clinical accuracy and are available in the U.S.
Use an upper arm, automated device
“Home blood pressure measurement devices should have upper arm cuffs and automatically inflate,” said Dr. Rakotz. “This means that you push a button to take the measurement so you don’t have to squeeze a bulb to manually inflate the cuff and use a stethoscope to obtain readings.”
“Patients also should use an upper arm cuff that is appropriately sized for their arm to get accurate measurements,” he said, adding that “home BP measurement devices typically come with a standard-sized cuff, so it’s helpful to make sure that the standard cuff fits a patient’s mid-upper arm appropriately. If the standard cuff does not fit, the device will not provide accurate measurements.”
“If you use too big of a cuff on a small arm, you could get a falsely low readings,” said Dr. Cole, noting it is important that a person measures their arm and then matches the size of the cuff to the size of their arm.
Prepare and position yourself properly
“Patients should rest quietly for five minutes while sitting in a comfortable position before measuring their blood pressure,” said Dr. Rakotz. “When taking a BP measurement, patients should sit with their legs uncrossed, feet supported on the floor or a firm surface, back supported and arm supported on a firm surface with the cuff at the level of the heart—which is about mid-chest.”
“A person should also not be talking when their blood pressure is getting checked. They should not have had any caffeine or cigarettes at least 30 minutes prior to getting their blood pressure checked because caffeine and cigarettes can falsely elevate blood pressure.”
“You should also empty your bladder because a full bladder can raise blood pressure. The details matter. The circumstances under how that blood pressure is measured matter,” he said.
“Most measurement-related errors increase blood pressure temporarily,” Dr. Rakotz said. “This can be a real problem if a physician is trying to diagnose or treat blood high blood pressure based on home readings.”
“If a person can get into the habit of taking their blood pressure at home and they learn that proper technique, then they can make sure they're getting us good, reliable, accurate blood pressures,” said Dr. Cole.
How often to measure BP
“Two blood pressure measurements, one minute apart, should be taken each time home measurements are performed. Measurements should be taken in the morning and evening,” said Dr. Rakotz. “Again, that’s two blood pressure readings, one minute apart, twice daily for seven days. If all of these measurements are taken, that will add up to 28 readings in a one-week period.”
“Make sure all measurement results are shared with the physician and care team,” he said, adding that “based on the results the physician will make treatment decisions and recommendations.”
How to communicate BP readings
“There are several options for communicating blood pressure results back to a physician or care team,” said Dr. Rakotz. “Patients can write their readings down on a blood pressure measurement log, or if the device has memory, they can bring it to the office to be reviewed.”
“Some devices can be connected to mobile phones or apps and the BPs can be securely transmitted to the physician and care team,” he said. Additionally, “some apps have the ability to transfer readings directly to the physician and care team, and some apps have secure portals where measurements can be viewed.”
“In our program at Ochsner, it’s automatic. It’s a wireless remote blood pressure cuff that’s connected to the internet that then sends it to the cloud and the cloud sends it into our electronic medical record,” said Dr. Cole. “For those health systems and physicians who don’t have that automated way of getting a blood pressure into the electronic medical record, patients may call in their readings or bring in their sheet of paper with their blood pressure numbers.”
“It can also be electronically sent through the portal where a patient can either send in their readings or screenshots of an app they use to monitor their readings,” he said. “But by far the best is when it’s just automatic, and the patient doesn’t have to do anything. It comes right to the doctor.”
“I also always suggest writing all the measurements down to have a backup on paper,” Dr. Rakotz added.
What to do if your BP is high
“Make sure there are clear instructions so patients know what to do if the blood pressures taken at home are higher or lower than expected” said Dr. Rakotz, emphasizing that “patients and physicians should make a plan together.”
For example, “if your blood pressure was much higher than usual and you have symptoms, your doctor might want you to call right away to discuss, or have you go to an emergency room, but if it's only slightly higher than usual your doctor might want you to recheck it again after five minutes, or even the next day,” he said. “Every patient has different levels of risk so instructions and plans will vary and your doctor will have a plan just for you.”
Why wearables aren’t recommended
Many people choose to wear smartwatches, fitness bands or other devices to track their exercise or monitor other aspects of their health.
But while “the technology is advancing rapidly, we still don’t have enough evidence to recommend regular use of these direct-to-consumer wearable devices for the diagnosis or clinical management of high blood pressure,” said Dr. Rakotz.
These wearable devices are not accurate enough for blood pressure yet, says Dr. Cole.
“I would imagine that day will come within our lifetime, but it’s not here yet,” said Dr. Cole. When Apple received Food and Drug Administration (FDA) approval for blood pressure measurement with the Apple Watch, “it was not based on accuracy of the readings. It was based on comparability to other devices that may not necessarily be validated devices.
“They just had to prove that they could be as good as some of the other devices. But some of these other devices weren’t good,” he added, noting he personally would not rely on blood pressure readings from an Apple Watch. “The most it would do for me as a physician is signal to a person that they should at least come in and get their blood pressure checked,” he said.
“It gets us to be able to talk about it and now I can get a plan in place to build more readings with at-home blood pressure monitoring with an upper arm cuff that is validated,” Dr. Cole said. “Then we’ll make our determination based on those readings.”
High BP treatment goals have changed
“When I finished my medical training, 140/90 mm Hg or higher was considered high blood pressure. Now it’s 130/80 or higher,” said Dr. Cole. “We used to have designations such as mild, moderate and severe hypertension. We no longer have those designations.”
“Part of the reason is because we would never want to give the impression that any degree of hypertension is mild,” he explained. “Instead, we call it stage 1 hypertension and stage 2 hypertension. When a person has stage 2 hypertension—which means their blood pressure is higher than 140/90 mmHg — then two blood pressure medicines are indicated rather than one.”
“For the majority of people with high blood pressure, it takes two to three blood pressure medicines to control the blood pressure,” Dr. Cole said. “It is incredibly important to get the blood pressure controlled, and we aim to get systolic down for most patients in the low 120s or even below 120.”
Don’t be afraid of BP medications
Dr. Cole says that we’ve come a long way in terms of the medications that are available to treat high blood pressure.
“We have lots of really good, well tolerated blood pressure medicines,” he said. “So, don’t be afraid of the medications. You should be more afraid of the disease of high blood pressure than you should be afraid of the medicines.”
