How accurate is your home blood pressure monitor? Readings can determine whether someone is put on medicine or not. How would you even begin to determine whether your measurements are accurate? Because we are told that hypertension affects half the adult population (over 100 million people) it is crucial that blood pressure readings are trustworthy. This article in JAMA (May 2, 2023) raises some some disturbing questions about the validity of many home units.
Why is Home Blood Pressure Monitor Validation Important?
When you buy a watch you expect it to keep accurate time. Ditto for other monitoring or measuring devices. You want the temperature gauge on your dashboard to let you know immediately if your engine is overheating.
The same thing is true for your home blood pressure monitor. A device that reads consistently above or below the true value could lead to over or under treatment of hypertension. That could have important health consequences.
Researchers writing in JAMA describe their methodology regarding home blood pressure monitor validation:
“A prospective analysis of the 100 best-selling lists of BP devices sold by Amazon was undertaken every 8 weeks for a year, beginning February 2020, across 10 countries with available data (Australia, Canada, France, Germany, India, Italy, Mexico, Spain, United Kingdom, and United States). The best-selling lists are the ‘most popular products based on sales.’
“Validation status of devices was determined from international listings STRIDE-BP and Medaval and country-specific listings where relevant (eg, US Blood Pressure Validated Device Listing for data from the United States only). Devices were considered validated if reported as such on any validation listings and nonvalidated if they were not on any lists.”
What The Researchers Discovered:
In the US, 84% of the upper arm devices were nonvalidated and 100% of the wrist monitors were nonvalidated. The nonvalidated products were almost always cheaper than the validated ones.
The authors conclude:
“Among the top 100 best-selling BP devices on a popular online site, 79% of upper arm and 83% of wrist cuff devices were nonvalidated. The predominance of nonvalidated devices may have adverse consequences for management of hypertension; therefore, clinicians should ensure they are recommending validated devices to their patients.”
The authors warn that consumers purchasing such blood pressure monitors online cannot be confident that they are accurate and recommend that:
“Policies should be implemented to require clinical validation of devices.”
We could not agree more! The Food and Drug Administration is responsible for medical devices. It should be requiring that all BP monitors sold in the US be validated.
Seeking An Accurate Home Blood Pressure Monitor:
This reader asks a relevant question:
Q. Are home blood pressure monitoring machines accurate? I have had some trouble with mine over the years. My readings fluctuate quite a lot. I know variability is normal, based on activity level, stress or whether one just drank coffee. My average with random readings over the last week: 133/87.
My resting heart rate is in the high 80s or low 90s. When I was taking a low dose of atenolol last year, my heart rate was usually in the 60s. What should I make of this? I am a 63-year-old woman with no known heart disease.
Assessing the Accuracy of a Home Blood Pressure Monitor:
A small study conducted in Canada has concluded that too many home monitors do not measure blood pressure well enough (American Journal of Hypertension, July, 2017). The investigators had 85 patients bring in their home blood pressure monitor. Each one was used to measure that person’s blood pressure in the clinic.
This was compared to blood pressure taken at the same time with a mercury sphygmomanometer, the gold standard device for blood pressure measurement. Two people were listening for the sounds and paying attention to the pressure measured with the sphygmomanometer.
Was There a Difference in Blood Pressure?
About 70 percent of the time, there was a 5 mm difference between the two measurements. Even more worrisome, the scientists found a 10 mm or greater difference for about 30 percent of the devices.
A home blood pressure monitor was most likely to diverge on its readings for systolic pressure. That is the higher number, and the one that is stated first in a standard report of blood pressure. In other words, when you say blood pressure is 120/80, the systolic pressure is 120.
The discrepancies were seen most frequently in men with large arms. Since arm size is known to affect the accuracy of blood pressure readings unless the cuff is well-matched to the arm size, this is not a big surprise. It does suggest that people should have more guidance when they are purchasing a home blood pressure monitor for themselves.
A recent review in the Journal of Human Hypertension (Feb. 2023) reported that:
“Unfortunately, most BPMDs [blood pressure measuring devices] sold on the global market have not been clinically validated.”
Some Blood Pressure Monitors that Are Accurate:
Consumer Reports has evaluated many different models over the decades. The Omron brand consistently ranks very highly for ease of use and accuracy. Prices range from roughly $50 to $100. They have also created cuffs that accommodate a variety of arms and are easy to put on and.
We recommend checking your device by taking it with you to your next in-person doctor’s visit. Have the nurse measure your blood pressure several times in the same arm with both devices to compare the readings.
HOW You Take Your Blood Pressure is REALLY Important!
Even when your blood pressure monitor is perfect, you can still screw up your readings by taking your blood pressure incorrectly. You will be surprised to learn how often health care professionals make mistakes when it comes to measuring blood pressure. Here is an article that we have written on this topic:
Seven Mistakes to Avoid When Measuring Blood Pressure!
Do you avoid mistakes when measuring blood pressure? We are constantly amazed at how many technicians incorrectly take blood pressure readings. Here are tips to help you eliminate errors.
What About Atenolol?
The reader who asked the question above about a home blood pressure monitor also wanted to know about atenolol for treating hypertension.
Atenolol is a beta blocker that can lower blood pressure and slow heart rate. Beta blockers are no longer considered first-line treatment for hypertension by most cardiologists.
Your resting heart rate is a bit higher than usual, however, so your physician may want to reconsider whether a beta blocker might be appropriate. Your blood pressure is slightly above the current target of 130/80.
You can read more about proper blood pressure measuring technique and a variety of ways to manage hypertension in our eGuide to Blood Pressure Solutions. There are also specific Omron models to choose from. It is in our Health eGuides section of this website.
Please share your own experience with blood pressure measurement either in the doctor’s office or at home in the comment section below.
