Popular blood pressure app inaccurate

A new research has revealed a popular app that measures blood pressure simply by placing a smartphone on the chest with a finger over the built-in camera lens is inaccurate, missing high BP mark in eight out of 10 patients.

Although the app, called Instant Blood Pressure, is no longer available for purchase, it was downloaded more than 100,000 times and is still functional on phones, the Johns Hopkins researchers say.

Researcher Timothy B. Plante said that they 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.

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.

The authors Plante and Seth Martin say that it is unclear how the app arrives at a blood pressure number. They suggest in the study that, rather than attempting to measure true blood pressure, the app gives a population-derived estimate based on the user's age, sex, height, weight and heart rate, the latter of which could be detected by the phone's microphone.

"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."

Martin and Plante note that mobile health smartphone applications are becoming more commonplace and many have the potential to greatly improve health by putting personalized medical resources and information literally in the hands of patients through cellphones.

The study appears in JAMA Internal Medicine.