Popular blood pressure app inaccurate

March 3, 2016

Instant Blood Pressure, a popular smartphone app, gave inaccurate readings for eight out ten patients, according to a John Hopkins study.

The app measures blood pressure by placing the phone a person’s chest and placing a finger over the phone’s camera. The app is no longer available in app stores, but was already downloaded by more than 100,000 times.

“We think there is definitely a role for smartphone technology in health care, but because of the significant risk of harm to users who get inaccurate information, the results of our study speak to the need for scientific validation and regulation of these apps before they reach consumers,” says Timothy B. Plante, M.D., a fellow in the Division of General Internal Medicine at the Johns Hopkins University School of Medicine.

Plante and co-author Seth Martin, M.D., M.H.S. undertook the study because “we were skeptical that even very talented people could design an app that could accurately measure blood pressure in such a different way,” Martin says. “Because of the absence of any rigorous scientific testing, there was no evidence that it worked or didn’t work.”

Results showed that blood pressures measurements from the app were overwhelmingly inaccurate. Close to 80 percent of those with clinically high blood pressure, defined as 140/90 millimeters of mercury or above, measured by the automated blood pressure monitor showed normal blood pressure with the app.

“Because this app does such a terrible job measuring blood pressure,” says Plante, “it could lead to irreparable harm by masking the true risk of heart attacks and strokes in people who rely on the accuracy of this information.”

Though the results of this study were discouraging, they say improvements in the technology could make blood pressure measurement apps accurate and useful. The app studied here, which cost US$4.99 when it was sold, was removed from Apple’s App Store in late August 2015 for reasons that are unclear.

“The next big step in health care is to further engage folks in their own care and motivate them to reduce risks associated with diseases like high blood pressure,” Plante says. “But care must be taken to make sure they get the accurate ways to do that.”

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