BP here, there, and everywhere – mobile health applications (apps) and hypertension care

Abstract

High blood pressure (BP) is a life–long condition. People with hypertension need to monitor their BP, take medications every day, and see their doctor periodically. Furthermore, lifestyle behaviors including salt intake, physical activity, diet, and weight influence BP control, but change is difficult, and most people need help. 1 Currently over 90% of American adults own a cell phone, and over half of these adults own smartphones. Thus, mobile health applications (m–health apps) provide hypertension patients with a promising platform for monitoring, tracking and managing their BP. This issue of JASH includes a study by Kumar et al 2 examining the content of m–health hypertension apps. Over a period of 2 days in Spring 2014, they found more than 200 hypertension and BP apps for iPhones on Apple iTunes and for Android smartphones on Google Play. They reviewed 107 from the top search results. Most apps targeted patients: less than 3% targeted doctors, and only 2% targeted both doctors and patients. The most common function was tracking BP and pulse, followed by tracking weight/body mass index, medication adherence (eg, with alarms, medication logs) and, less frequently, salt and/or caloric intake. Other common features included charts and graphics for monitoring BP and pulse trends, tools for text–based feedback about high and low BP readings, and educational materials (eg, information on hypertension or the Dietary Approaches to Stop Hypertension [DASH] diet). Most of the reviewed apps were inexpensive or free. A new, innovative, and popular app feature transforms the smartphone into a BP–measuring device. Kumar et al report that between 1 and 2 million people have downloaded this type of app. After reading this review, I tried out an app that uses the iPhone camera and microphone to capture BP and pulse. Putting my finger on the camera lens and pressing the phone against my chest produced a BP measurement that seemed reasonable for me. Because smartphones can be used anywhere, an app that turns a phone into a BP–measuring device would make it possible for billions of people to regularly check their BP status, making it a potentially important tool for improving BP control globally. In fact, meta–analyses provide evidence that self–BP monitoring alone results in modest reductions in BP. 3 Unfortunately, however, there is no evidence that any of the smartphone–based BP–monitoring apps have been independently validated with an approved protocol, such as the US Association for Advancement of Medical Instrumentation (AAMI). Thus the accuracy of BP measurements taken with smartphones is unknown, and apps that convert mobile phones into BP–measuring devices cannot be promoted at this time. Kumar et al’s review did not include smartphone apps that receive data from an external BP cuff, such as the Withings or iHealth BP monitors. These were not included because the app is downloaded directly from the cuff manufacturer instead of through the iTunes or Google Play stores. A published study found that the Withings BP–800