Popular Blood Pressure App Unreliable for Hypertension Readings

March 15th 2016

When it comes to accurately checking a patient’s blood pressure, retail clinicians are a safer bet than a mobile app.

When it comes to accurately checking a patient’s blood pressure, retail clinicians are a safer bet than a mobile app.

A research letter recently published inJAMA Internal Medicinefound that the popular Instant Blood Pressure app is “highly inaccurate.” In fact, the mobile app misclassified hypertensive-range blood pressures as nonhypertensive 77.5% of the time, author Tim Plante, MD, a clinical fellow in general internal medicine at Johns Hopkins University, toldContemporary Clinic.

On average, the app was about 12 mm Hg off for systolic blood pressure measurements and 10 mm Hg off for diastolic blood pressure measurements.

“Screening for hypertension is best done in the clinical setting, though I think there is a role for folks to check their own blood pressures at home, as long as they are using a validated, accurate device and they follow up with a provider if the result is consistent with hypertension,” Dr. Plante said.

Dr. Plante and his fellow researchers decided to examine the app after hearing concerns about patients relying on it to assess their blood pressure and titrate therapy.

To study how the app worked, the researchers enrolled patients and staff from 5 ambulatory Johns Hopkins sites from August to September 2015. Of the 85 participants, 52% were female, about 53% of self-reported hypertension, and 91% took antihypertensive medications.

The research staff was trained on how to use the blood pressure app on iPhone 5s and 6. For a standard blood pressure measurement, the staff followed standard protocol using calibrated, validated automated sphygmomanometers. (The standard blood pressure measurement was an average of 2 measurements by sphygmomanometry.)

After the subjects sat quietly for 5 minutes, the research staff took blood pressure readings from both devices, 60 seconds apart. They found that the Instant Blood Pressure app underestimated higher blood pressures and overestimated lower blood pressures.

“The low sensitivity for hypertensive measurements means that approximately four-fifths of individuals with hypertensive blood pressure levels will be falsely reassured that their blood pressure is in the nonhypertensive range,” the researchers wrote.

Although the app is no longer available “for unclear reasons,” it may still be downloaded on patients’ phones. In addition, research on the reliability of similar iPhone apps such as Blood Pressure Pocket and Quick Blood Pressure Measure and Monitor has not yet been conducted.

The Instant Blood Pressure app was available from June 5, 2014, to July 30, 2015, and was one of the 50 best-selling iPhone apps for 156 days. In addition, at least 950 copies of the $5 app were sold on each of those days, according to the authors of the research letter.

To take a blood pressure reading with the app, users were instructed to place the edge of their smartphone against the left side of the chest while placing their index finger over the phone’s camera.

The researchers suggested that app developers, distributors, and regulatory bodies partner to follow standards for safe and validated mobile health technologies.

Related Content