Study warns against ‘inaccurate’ blood pressure mobile app

A popular smartphone app that claims to measure blood pressure is highly inaccurate, and may mislead users about their health, said a US study on Wednesday.

The app - known as Instant Blood Pressure - has been downloaded more than 100,000 times, and is still operational despite being made unavailable for purchase, said the study by researchers at the Johns Hopkins University School of Medicine. The app, earlier available for $4.99, was removed from the Apple store in August 2015 for unspecified reasons.

The study said that the mobile application, which requires the cellphone to be placed on the chest with a finger over the built-in camera lens for measuring blood pressure, claims to be accurate in its readings. However, it "misses high blood pressure in eight out of 10 patients, potentially putting users' health at risk", it added.

"Because this app does such a terrible job of 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," said Timothy Plante, a fellow in the Division of General Internal Medicine at the Johns Hopkins University School of Medicine.

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The study, which was published in the Journal of the American Medical Association (JAMA) Internal Medicine, used 85 volunteers to arrive at its conclusion. It said that the best way to measure blood pressure is by "inflating a cuff, attached around the brachial artery in the arm, to detect the force of blood flowing when the heart is beating and at rest".

The measurement based on the cuff reading should be taken by either a machine or a medical professional, it added.

"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 highlight the need for scientific validation and regulation of these apps before they reach consumers," said Plante.