Dive Brief:
- Apple Watch’s hypertension notification feature may miss some cases across different patient demographics, according to a research letter published last week in JAMA.
- Researchers at the University of Pennsylvania and University of Utah applied performance metrics for the feature to U.S. population statistics to estimate its impact. They found about 69% of people who received an alert have hypertension, and about 79% of people who don’t receive an alert do not have hypertension. The feature’s performance varied by age, race and ethnicity.
- Jordana Cohen, the study’s lead author and an associate professor of medicine and epidemiology at the University of Pennsylvania School of Medicine, wrote in an email that the analysis suggests an alert meaningfully increases the likelihood that a person has hypertension. “However, the absence of an alert provides limited reassurance, particularly in older and higher-risk adults, and routine blood pressure measurement with validated cuff-based devices remains essential,” Cohen wrote.
Dive Insight:
Apple’s smartwatch feature, cleared by the Food and Drug Administration last year, is not intended to diagnose hypertension. It notifies users of patterns from the device’s optical heart sensor that could indicate potential high blood pressure.
Apple provided results of a validation study to the FDA showing that about 41% of people with undiagnosed hypertension received an alert, and nearly 59% did not. Among people without hypertension, 7.7% received an inappropriate alert.
The feature could help a large proportion of individuals who were unaware of their hypertension, the researchers wrote. “However, an even larger proportion of individuals with undiagnosed hypertension could receive no alert at all.”
Researchers applied these results to a cross-sectional survey of the U.S. population. They found disparities in how accurate the feature is across different patient demographics.
In groups where undiagnosed hypertension is more prevalent, alerts are more likely to represent true hypertension, while the absence of an alert is less reassuring.
For example, for adults 60 and older, an alert increases the probability from 45% to 81%. People in this group who don’t receive an alert still have a 34% probability of having undiagnosed hypertension, according to the study.
The performance of the alerts also varied by race and ethnicity, reflecting disparities in cardiovascular health driven by social determinants. Among non-Hispanic Black adults, the researchers found an alert increases the probability of having hypertension from 36% to 75%, and the absence of an alert lowers it to 26%.
The researchers cautioned that false reassurance may lead to missed opportunities for early detection and treatment. They added, “Rigorous validation, strategies to improve cuffless device accuracy, and thoughtful integration into population screening will be essential if cuffless technologies are to contribute meaningfully to hypertension detection.”
