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SAN DIEGO -- For a given individual, blood pressure (BP) readings were largely the same coming from a cuffless photoplethysmography (PPG)-based monitor or a traditional cuff-based device -- regardless of the person's sex, BMI, or skin color, a study showed.

Calibrated to a cuffed device and used for cuffless wrist- and chest-based BP measurement, the Biobeats sensor consistently had BP measurements correlate strongly with parallel readings from the cuffed device. This was observed in men and women, across a range of BMI, and in lighter and darker skin tones alike, according to Arik Eisenkraft, MD, of Biobeat Technologies of Petah Tikva, Israel and the Hebrew University in Jerusalem.

Eisenkraft noted that nearly 80% of cuffless measurements differed by less than 5 mmHg from control readings; almost none of measurements went beyond a 10-mmHg difference. This adds evidence of the highly similar results produced by the two BP measurement methods, he said.

The study was prompted by concerns that PPG-based devices give inaccurate readings and may be led astray by subcutaneous fat and darker skin color. "FDA asked us to provide or conduct a comparison study to see whether measurements are in high correlation with cuff-based devices in various populations," he stated in a presentation at the Hypertension meeting hosted by the American Heart Association.

Biobeat's wearable remote patient monitoring device has received for the measurement of respiratory rate, body temperature, BP, blood oxygen saturation, and pulse rate.

During the session Q&A, Michael Lee, MD, of Kaiser Permanente Southern California in Rancho Cucamonga, asked about the impact of a person's position -- lying down or standing up -- on the Biobeat's performance. He cited a study, also presented at this Hypertension meeting, that had found cuffless BP measurements to correlate well with standard ambulatory monitoring during daytime but not nighttime.

Lee commented that cuffless technology has a lot of potential to be used as a 24-hour BP monitor and if it works standing or sitting, "that would be ideal."

Eisenkraft reassured that "this is not an issue" for this particular device but cautioned that there are several cuffless BP monitor companies with different sensors that he cannot comment on.

Speaking of the competition, he said "we share a lot of frustration mainly because there are no clear [regulatory] guidelines when looking at cuffless BP devices ... We have a lot of data and we feel the medical community's still not there looking at the tremendous capabilities of such technologies."

Discussion co-moderator Paul Muntner, PhD, of the University of Alabama at Birmingham, nevertheless pointed out the concern that changing cuffless BP readings over time may be tied more to their dwindling calibration value rather than true BP change.

According to Eisenkraft, the Biobeat sensor currently stands for 3 months of accurate measurements between recalibrations, but there may be upcoming data to show that calibration can occur less frequently. "The long-term aim is not to use calibration at all," he said.

For the study, the authors relied on Israel's infrastructure of widespread BP measurement stations. Investigators had more than 1,500 ambulatory individuals undergo cuff-based and cuffless BP measurement at the same time. Volunteers underwent the process once or twice a month.

Participants averaged age 35, and 42.9% were men. Mean BMI was 24. By skin tone, the cohort was divided between the 60% categorized as Fitzpatrick 1-3 (very fair to medium) and the remaining 40% Fitzpatrick 4-6 (olive to black).

Attendee Gbenga Ogedegbe, MD, of NYU Langone Health in New York City, pressed the issue of skin color. He pointed out the potential spectrum bias arising from an insufficiently wide range of skin color categories in the study.

"We are working intensively with countries such as South Africa, French Congo, and other African countries. This gives us a lot of valuable data looking specifically at darker tones, which are usually considered more challenging for this technology," Eisenkraft noted.

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