When shopping for a blood-pressure cuff to use at home, most patients will buy the cheapest model without giving much thought to the fit. But four of the top selling devices on Amazon aren’t even approved by the Food and Drug Administration. This can lead to bad data and suboptimal treatment of hypertension.
The results of a study presented at the Hypertension Scientific Sessions and published in the journal Hypertension underscore the problems associated with over-the-counter BP devices and incorrect cuff size. Many people with hypertension have arm sizes too large to ensure accurate readings with commonly used devices, the researchers found.
“Device companies and retailers should improve the availability and access to larger cuffs for those individuals with large arm circumferences,” Kunihiro Matsushita, MD, PhD, the study’s corresponding author, said in an interview.
Amassing some of the most popular home BP devices on Amazon, investigators used National Health and Nutrition Examination Survey data from 2015 to 2020 to quantify the number of U.S. adults whose arm circumference rendered them ineligible for these devices. The study included 13,826 adults without concurrent pregnancy and missing information on arm circumference.
“We applied the prevalence estimates to the 2023 U.S. census and obtained our estimates on relevant numbers in millions,” explained Dr. Matsushita.
Among 10 devices selected, nine offered cuff sizes covering arm circumferences from 22 to 42 centimeters. Based on the federal survey data, 6.7%—or roughly 17 million U.S. adults—were ineligible for these devices. About 0.3% had an arm circumference of less than 22 centimeters, including 32.3% with hypertension.
Larger cuff sizes are needed
The vast majority—6.4%, or 16.5 million—had an arm circumference of more than 42 centimeters while 67.3% of these individuals had hypertension.
“There are two major components that make one’s arm circumference large: muscle and fat. Thus, overweight and obesity are likely to play a role at least partially,” said Dr. Matsushita, a cardiologist and professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health in Baltimore.
Another unsettling finding is that one in eight Black adults weren’t eligible for devices without an extra optional cuff—higher than any other race or ethnicity. Most devices come with a single cuff, so consumers with a large arm circumference need to purchase a larger cuff, if available, to make the device work for their arm size.
“Our observation indicates that Black adults are more likely to have arm circumference exceeding the limits of cuffs in those popular devices, and that is likely due to muscle or fat mass,” said Dr. Matsushita, citing data.
Regardless of the reasons, the investigators urged that manufacturers develop affordable BP measuring devices with arm circumferences of greater than 42 centimeters.
How cuff size affects BP readings
“Using the incorrect cuff size can lead to both under and overstating blood pressures,” said AMA member Samuel “Le” Church, MD, MPH, a family physician who champions education on self-measured BP (SMBP) monitoring in Georgia.
Cuff sizes that are too small mistakenly lead to higher BP readings nearly 40% of the time, added Dr. Church, citing a study in JAMA Internal Medicine.
Cuff selection is more about the arm size and shape rather than the underlying demographic, he explained. People with a mid-upper arm circumference exceeding 34 centimeters may need large or extra-large cuffs. Patients with arms smaller than 26 centimeters should use a small cuff.
“Generally, upper-arm cuffs are preferred, but if the arm is irregularly shaped, a wrist cuff may be appropriate,” Dr. Church advised.
People who are pregnant also represent a high-risk demographic that needs better BP monitoring and may struggle with cuff sizes. But Medicare populations represent the largest concentration of patients at elevated risk for atherosclerotic cardiovascular disease.
“Currently, BP cuffs aren't covered. Maybe that will change in the future given the significant return on investment in terms of health and resources,” said Dr. Church.
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Progress at the state level
SMBP can be an effective tool for blood-pressure management, Dr. Church said. Although BP monitors are relatively inexpensive, their cost is a significant barrier for socially and economically marginalized patients, he added. The AMA has been working to increase payer coverage for more cuff sizes and ensure patients are using the right cuff size.
The US Blood Pressure Validated Device Listing (VDL™) can be used to find blood pressure-measurement devices that have been validated for clinical accuracy and are available in the U.S. In 2020, 16 BP measurement devices met the requirements to be listed as clinically accurate after the testing data was submitted by their manufacturers for review.
Now that number has grown to 102 and includes home and in-office upper arm devices, wrist cuff devices, community kiosks and 24-hour ambulatory monitors. Discover why a validated device listing is important for BP control.
Part of this work included the AMA working with the Medical Association of Georgia to get regulatory language passed that covers devices listed on the VDL under Medicaid. While Dr. Church wasn't personally involved in that work, he remarked that “working to reduce cardiovascular disease events with low-cost interventions is a unifying topic.”
The AMA also collaborated with the Michigan State Medical Society to develop guidance to assist physicians and care teams in ordering SMBP and validated devices for their patients. Additionally, the AMA worked with the Medical Association of Georgia for specific guidance for the state.
Setting a culture for BP checks
“Given the overwhelming impact of proper blood-pressure control in reducing cardiovascular disease, this topic should be a high priority for every patient,” said Dr. Church.
But physicians can't do this alone, he stressed. Physician leadership is essential for the team to set a prioritized tone and culture for the clinic and health system. That means workflow for the team should be adjusted as well. This might include encouraging repeat BP checks in the office and developing processes to educate and encourage SMBP for patients.
“The loop still needs to be closed though. How your team manages blood pressure logs and interacts with the provider for interpretation is critical,” Dr. Church said. “As part of that workflow, working knowledge of related billing codes should be integrated to support the associated work.”
Code 99473, for example, covers sizing and education regarding use of BP cuffs and monitors, he said. Meanwhile, code 99474 covers the interpretation and communication of treatment plans related to BP logs. Other codes may be more appropriate in some settings such as remote monitoring and care management.
AMA MAP™ Hypertension, an evidence-based quality improvement program that provides a clear path to significant, sustained improvements in BP control. With the AMA MAP program, health care organizations can increase BP-control rates quickly. The program has demonstrated a 10% increase in BP control in six months with sustained results at one year.
