Hundreds of cuffless blood pressure devices are available to consumers worldwide right now. Accessible on phones, watches, rings and patches, they’ve grown in popularity due to their convenience to patients.
While they’re easily accessible on Amazon, most of these devices have not undergone any type of regulatory evaluation. They need further testing and validation, an international panel of researchers recommended in a paper published in JAMA Cardiology.
The technologies are promising and exciting, but the rapid pace of their development is making it challenging to appropriately test them for accuracy, cautioned Eugene Yang, MD, MS, a cardiologist and professor of medicine in Seattle, Washington, and the paper’s lead author.
Many of these devices haven’t undergone appropriate validation because those validation protocols don't exist, Dr. Yang said in an interview.
“Whether you're a consumer or a clinician, the key point is that we should not rely on data from these devices,” he said. “We need to focus on using validated cuff devices until more research is done and appropriate validation protocols have been established.”
Hypertension experts—including the AMA—began meeting in 2015 to design a set of criteria for what would be required for BP measurement devices to be considered validated and accurate for clinical use. What emerged is now the US Blood Pressure Validated Device Listing (VDL™), a free resource available at validatebp.org that administrators, physicians and care teams can use to identify BP devices that have been validated for clinical accuracy, ensuring that patients are using validated devices to share reliable readings back to them.
Accurate BP measurement is a critical part of treating hypertension. But getting patients to take their BP is challenging from the clinician’s standpoint, noted Dr. Yang. It requires people to sit quietly for five minutes and use a cuff device that insufflates and causes some discomfort to the arm.
“If there was an easier way to do it, it would become more attractive because then we would be able to get the information and patients would have more ease and convenience of doing the blood pressure measurement,” he said.
Dr. Yang and his coauthors completed a comprehensive review to arrive at their recommendations about cuffless BP devices. Despite their appeal, validation of cuffless devices should be the chief priority before deploying them for public use. Accuracy with risk of undertreatment or overtreatment remain key concerns, the authors write.
Validation protocols needed
Only a handful of cuffless devices have received regulatory clearance from the Food and Drug Administration (FDA) or European CE Mark, the JAMA Cardiology investigators reported.
There are hundreds of other devices that regulatory bodies haven’t evaluated or validated, said Dr. Yang.
A key issue is current validation protocols are designed only for cuff devices, he explained. Cuffless devices represent a wide range of technologies that are very different from the oscillometric cuffs normally used for home measurement.
“The devices have not had specific protocols developed for them. As a result, companies who are developing the technologies are relying on validation protocols that are not appropriate,” he explained.
Getting FDA clearance or CE mark for some devices requires calibration with a cuff device, but not all of them. This means taking a measurement with a cuff device first, then pairing it with the device the patient is using, such as a ring or a watch. The device isn’t actually measuring the blood pressure, he clarified. They’re estimating changes relative to the baseline measurement from the cuff device.
Bottom line is these cuffless technologies are very complicated. This is why it’s imperative that they’re appropriately validated, he emphasized.
Cuffless options may be less expensive than traditional, validated cuff options, which could improve out-of-office accessibility of BP monitoring. However, those cheaper devices need an infrastructure to support them, noted Dr. Yang. “If you don't have access to the tools that allow you to use the devices, then it may worsen disparities that already exist.”
Security and privacy pose other concerns.
“How do you ensure the security of information that may go directly into somebody's electronic health record? There's always going to be security and data privacy issues for any kind of technology like this,” he added.
The elusive “one protocol for all”
Some international societies are interested in measurement technology to create specific standards for cuffless devices. The European Society for Hypertension in 2023 published validation protocols for intermittent cuffless devices, as well as recommendations for testing the devices. Other organizations are also stepping forward to create standardized protocols.
One potential barrier is there’s lack of consensus on how to create them.
The diversity of cuffless technology also makes it difficult to establish one protocol for all devices. Because cuffless technologies use different algorithms to estimate BP, there might need to be tailored protocols that are specific to the technologies incorporated into these devices, he added.
Whatever the outcome, a regulatory body or agency needs to establish these standards—not just for patients, but for clinicians, said Dr. Yang.
Whenever he asks a patient to measure their BP at home, Dr. Yang advises them to use a validated BP cuff device.
“They just need to understand that these devices have undergone appropriate validation protocols and feel confident that the blood pressure measurements are accurate,” he said.
Focus on validation
AMA, in the meantime, is closely monitoring the cuffless BP measurement device landscape. While there has been exciting innovation in this area, “the authors have it right in concluding that clinicians and patients should only use validated BP cuff devices until cuffless BP measurement devices are appropriately tested and validated,” said Kate Kirley, MD, MS, AMA’s vice president for prevention solutions.
In overseeing the US Blood Pressure Validated Device Listing (VDL™), available at validatebp.org, the AMA would need to see several gaps addressed before considering the inclusion of cuffless devices on the listing, said Dr. Kirley.
“These unresolved issues include the development of appropriate validation protocols, establishment of a defined regulatory approach, and clear guidance to clinicians regarding how to interpret and utilize cuffless device readings in their care,” she said.
To address and manage hypertension for now, physicians and other health professionals should use either validatebp.org or its European counterpart, Stride BP, to find validated BP measurement devices for their patients, advised Dr. Yang.
Only about 20% of U.S. BP devices used at home are validated and “we need to change that,” he said.
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