An app that measures your blood pressure through your smartphone is "highly inaccurate," according to a research letter published Wednesday in JAMA Internal Medicine. The app, Instant Blood Pressure, missed high blood pressure levels in nearly four out of five people, the researchers found.
The app's manufacturer fired back on Wednesday, arguing that the study was based on faulty methodology and thus invalid. The lead researcher defended the findings.
"This isn't something I want my patients using," says Dr. Tim Plante, a general internal medicine fellow at Johns Hopkins University and lead author of the letter.
The app is no longer available for sale, but it was popular between 2014 and 2015, with people buying 148,000 units, according to Plante and his colleagues. He's concerned that those who bought it will keep using it.
"If you have people who are using an inaccurate device like Instant Blood Pressure at home, and telling their doctor, 'my blood pressure is OK,' you could miss a risky high reading and develop complications from that down the road," Plante says.