When the Pressure’s On, This App May Not Be So Smart

Blood pressure smartphone app failed to measure blood pressure accurately

(RxWiki News) Smartphone apps can do some amazing things — deposit checks, manage stocks and teach French, to name a few. But they may have trouble measuring blood pressure.

A new study tested an app that claimed to accurately measure blood pressure and found that it missed high blood pressure in most patients.

The app “measured” blood pressure by asking people to place the smartphone on their chests with a finger over the built-in camera.

Though the app, called Instant Blood Pressure, is no longer being sold, it was downloaded more than 100,000 times and is still functional on phones, the authors of this study said.

High blood pressure often displays no visible warning signs, according to the Centers for Disease Control and Prevention. Because there is no symptomatic evidence to contradict the app, its users may be prone to believe its findings, these researchers noted.

"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," said study co-author Timothy B. Plante, MD, a fellow in the Division of General Internal Medicine at Johns Hopkins University School of Medicine, in a press release.

Dr. Plante conducted this study with co-author Seth Martin, MD, an assistant professor in the Division of Cardiology at the Johns Hopkins.

Drs. Plante and Martin said they decided to conduct this study because they were skeptical that even a very talented app designer could make this app functional. They said blood pressure is best measured by the well-known inflated-cuff-around-the-arm technique, which measures the force of blood flow when the heart is beating and at rest.

To conduct this study, Drs. Plante and Martin recruited 85 adults who were either patients or staff members at clinics associated with Johns Hopkins. The participants ranged in body mass measurements, races and ethnicities.

All participants had their resting blood pressure measured twice by an automated blood pressure monitor. The participants also used the app to measure their blood pressure twice on the same day.

The app was extremely inaccurate, Drs. Plante and Martin found. The app read nearly 80 percent of participants with high blood pressure — 140/90 millimeters of mercury or above — as being within the normal blood pressure range.

This app may be inaccurate because it simply makes a population-derived estimate, based on its user’s age, sex, height, weight and heart rate. It doesn't appear to actually measure blood pressure, these researchers said.

"Because this app does such a terrible job measuring blood pressure, 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," Dr. Plante said.

Instant Blood Pressure, which cost $4.99, was removed from Apple’s App Store in August 2015 for unknown reasons. Though this particular app was unsuccessful, the study’s authors said they have hope that improvements in technology will make blood pressure apps accurate, useful and accessible to many people.

This study was published in the March issue of JAMA Internal Medicine. It was supported in part by a P.J. Schafer Cardiovascular Research Grant and by the Institutional National Research Service Award-National Institutes of Health training grant.

Dr. Martin received grants from the P.J. Schafer Cardiovascular Research Fund.

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Review Date: 
March 3, 2016