Hypertension affects an estimated one billion people worldwide. In the United States, it’s estimated that nearly half of those with hypertension aren’t meeting their blood pressure goals. And as we’ve recently highlighted with our reviews of the iHealth, Qardio, Withings blood pressure monitors, self-monitoring can be a useful tool to more effectively manage hypertension.

In addition to these monitors, there are innumerable apps available to help with blood pressure management. We recently did a literature review to identify important features that hypertension self-management apps should include. A group of researchers recently evaluated hypertension apps in the Google Play and iTunes apps stores.1

Methodology

They searched each app store using the terms “hypertension” and “high blood pressure,” and pulled information on the top 50 results for each. They found a total of 107 unique apps and recorded data like ratings, reported downloads (Google Play), and major functional characteristics of the apps.

Results

About 3% of the apps were developed by a healthcare organization and 95% of apps were targeted at patients.

The majority of the apps, 69%, were intended to be used for tracking blood pressure. Somewhat surprisingly, only 2.8% included functionality to track salt intake, 5% to track calories, and 27% to track weight. When it comes to changing behaviors, only 8% of apps included information on diets like the DASH diet. In terms of reminders, 10% included a medication reminder function and 20% a blood pressure check reminder.

As for results, a little less than half of the apps provided “normal or not” feedback. Disappointingly, only 44% of apps included functionality to share the data with a healthcare professional.

And perhaps most strikingly, they found 7 apps for Android that claimed to measure blood pressure directly – none referenced validation data. And these apps have been downloaded an unbelievable 900,000 to 2.4 million times. And when they looked at factors that made apps more popular, the strongest predictor turned out to be this blood pressure measuring functionality.

Discussion

One of the findings that was most striking in this study is how popular apps that claim to measure blood pressure directly, using the phone’s camera/flashlight, are. We highlighted this issue last summer when Dr. Husain wrote a piece on the Instant Blood Pressure app. He highlighted several questionable aspects of that app, including exaggerated claims of affiliation with Johns Hopkins and that they were charging for what they called a beta product that they’d labelled as “for entertainment purposes.”

The concept is being explored by others. Sotera’s popular ViSi Mobile platform claims to measure a continuous, cuffless non-invasive blood pressure. It does that by looking at when the heart beats, using an ECG tracing, and when that pulse arrives in the extremities basically using a pulse oximeter. That device however calibrates to a measurement taken with an wrist-worn blood pressure cuff built into the device. Even with that, Sotera’s own studies highlight problems with the non-invasive, cuffless measurement.

These apps are taking advantage of patients looking for easier ways to manage their health. And at up to 2 million downloads in Google Play alone, these apps are probably bringing in a decent chunk of change.

On the plus side, these were the minority of apps they found. Most seemed to offer useful functionality like tracking blood pressure. There are however clearly opportunities to improve the overall quality in the market if these apps would more consistently enable sharing with physicians, incorporate standard diet recommendations, and so on.

And it’s also important that we remember that our patients are seeking these tools out and that we offer guidance about how we can together use validated, useful tools to improve their blood pressure control.