New research suggests that home monitoring may help some people control high blood pressure
More than 100 million Americans have high blood pressure, according to the American Heart Association (AHA), but only about half of them have it under control.
Now preliminary research suggests that adopting a simple step—home blood pressure monitoring—can improve that outlook, helping many more people with uncontrolled hypertension get it under control.
When high blood pressure is not controlled, patients are at a high risk for heart attack, brain aneurysm, or stroke. And although previous studies have shown that a home blood pressure monitor can be very effective, only about a third of people with hypertension check their blood pressure at home at least once a month, according to the Centers for Disease Control and Prevention.
“The average physician is trying to see a patient every 10 to 15 minutes, so there’s barely time to go over medication, let alone talk about home blood pressure monitoring,” explains Roy Champion, M.Sc., B.S.N., a clinical quality nurse at Scott and White Health Plan in Temple, Texas, who presented the new research at an AHA conference.
Here, what you need to know about the new findings, and what to consider if you’re thinking about trying to monitor your own blood pressure at home.
What the New Research Found
The researchers provided free home blood pressure monitors—along with monitoring reminders and resources for taking and tracking readings—to 2,550 adults with uncontrolled hypertension, and followed the patients’ progress between December 2016 and June 2017.
By the third office visit, more than two-thirds (which was nearly 67 percent) of patients had their blood pressure under control. An even larger share of patients still had their blood pressure under control by the end of 2017.
“Physicians were able to adjust patients’ blood pressure medications either up or down based on the information from home monitoring, so that they were at the most appropriate dose,” says Champion.
By the end of the study, study subjects’ systolic blood pressure (the top number) had decreased an average 16.9 mmHg and diastolic blood pressure (the bottom number) fell an average 6.5 mmHg.
But while the results were dramatic, this was an observational pilot study that has not yet undergone peer review, and there wasn’t a control group. All of that means it’s too soon to say whether the results would apply in the wider population.
“Patients who agreed to be in this study and do the home monitoring may have been more motivated and would have had better outcomes anyway,” explains Swapnil Hiremath, M.D., M.P.H., a hypertension specialist and assistant professor of medicine at the University of Ottawa.
Still, “empowering patients and allowing them to access their own blood pressure numbers is very likely more effective than a five to 10-minute doctor visit,” he says. “Many patients are reluctant to take blood pressure medications—and to stick with them—because hypertension is such a silent disease. They feel fine, so in their minds they are fine. But when they see that those numbers go back up when they miss a dose, or eat a high fat, salty meal, then it’s a powerful incentive for them to stick to their drug regimen and adopt healthy lifestyle changes.”
(For more on who needs blood pressure medication and why you should try lifestyle changes first, see our previous coverage.)
Who Needs a Blood Pressure Monitor?
Although groups like the AHA and the American College of Cardiology have long recommended home blood pressure monitoring for patients with hypertension, it hasn’t caught on the way other simple self-testing strategies, like checking blood sugar at home for type 2 diabetes, have, notes Luke Laffin, M.D., a preventative cardiologist at the Cleveland Clinic.
This may be because it’s time consuming, and the monitors themselves, which aren’t covered by insurance, can be expensive. They don’t have to be: Consumer Reports has recommended models for as little as $29. Participants in the new study also had fewer doctor’s visits and lower ER and medication costs after regularly using a home monitor, according to Champion.
While anyone who has hypertension should consider a home monitor, says Laffin, it’s particularly important for the following groups of patients:
- Anyone starting high blood pressure medications, to make sure that they are on the right dose.
- Patients with other, coexisting conditions such as type 2 diabetes or kidney disease.
- Pregnant women who are developing signs of pregnancy-induced hypertension or pre-eclampsia.
- People who have had high or borderline readings in the doctor’s office, but need to confirm that they have true hypertension.
- People who may have “white-coat hypertension,” a condition where their blood pressure is normal at home but elevated when they’re nervous at a doctor’s office.
About 12 percent of American adults have a condition called masked hypertension, where their blood pressure is normal at the doctor’s office but elevated at home. So if you don’t have diagnosed high blood pressure, but your results are borderline at the doctor’s office, you may want to consider investing in a home monitor anyway.
Checking a home monitor periodically for a few weeks can be helpful in those cases, says Hiremath.
How to Choose a Blood Pressure Monitor
Consumer Reports has a buying guide that explains the different types of home blood pressure monitors and what you should know before buying one.
Home blood pressure monitors come in arm cuff, wrist cuff, and finger models. Of all three, the arm cuff models are the most reliable, says Laffin. (Finger models should be avoided completely, since they calculate your blood pressure by looking at the blood flow in your finger, which can be very inaccurate.)
You can pick a top scoring model using our blood pressure monitor ratings. It’s important to make sure that the blood pressure monitor is the right size for you: the cuff (most have two) should fit the circumference of your upper arm. If it’s too large or too small, it can result in inaccurate readings.
When you do purchase one, it’s important to choose one that gets high marks for accuracy—CR testers compare the BP reading from each model to the BP reading on a machine long considered the gold standard. You should also test your new machine in your doctor’s office, to make sure you’re using it correctly and getting consistent results.
A 2016 study done by Hiremath found that almost a third of home blood pressure monitors were off by at least 5 points. Another study, published in 2017, suggested problems with inaccuracy may be even more widespread.
Inaccurate readings can lead to dangerous miscalculations, cautions Champion. Plan to bring your monitor into the doctor’s office at least once a year to make sure it’s still working correctly, and never adjust your medication or treatment plan without consulting your physician.
How to Check Your Own Blood Pressure
A few precautions can help ensure that you’re getting the most accurate reading:
- Try to take your blood pressure at the same time every day. Levels are usually lowest first thing in the morning and rise steadily throughout the day.
- Don’t exercise, smoke, or consume caffeine for at least an hour before.
- Stay quiet. Talking can raise your blood pressure.
- Go to the bathroom right before, since a full bladder can raise your systolic pressure by as much as 15 points and your diastolic by 10 points.
- Make sure your feet are flat on the floor, legs uncrossed, and cuff at heart level.
- Put the cuff on bare skin, since putting it over clothes can raise your systolic pressure by up to 50 mmHg.
If you get a high reading, don’t panic, says Hiremath. Wait five minutes, then test again.
If the reading is only slightly higher than normal, take your blood pressure a few more times throughout the day and let your doctor know if it’s still elevated.
But if your blood pressure readings are over 180/120 mmHg, call your physician immediately, since that could mean a hypertensive crisis. (If you’re also experiencing symptoms such as chest pain, shortness of breath, or back pain, call 9-1-1.)
Likewise, if your blood pressure is unusually low, call your doctor, especially if you’re having symptoms such as feeling weak and dizzy. It can be a sign that you need to lower your medication dose.
Regardless, each time you take your blood pressure, make sure you record your results, either on paper or using an online tracker (some monitors also have built-in memory to store readings). Then share what you’ve recorded with your doctor at your next appointment.
Those results from home can help your doctor make the most informed decisions about your medications and the necessary treatment plan, says Hiremath, and can help determine whether an elevated reading in the office is a case of white-coat hypertension or a consistent problem.