THE 6TH VITAL SIGN: A MOBILE APP FOR POPULATION HEALTH SURVEILLANCE OF WALKING SPEED

Smartphone applications (apps) are a novel technique to directly reach people for research and health promotion. The 6th Vital Sign is an iPhone app designed using Apple’s Researchkit to enroll and consent adults in a study that measures a 2-minute walk test using the phone’s accelerometer, self-reported health, and demographics. On April 11, 2016 the app was uploaded into the iTunes store and was viewed in iTunes by 1,111 people during the first 50 days. There were 771 downloads, with 398 adults consenting to participate; 90.7% completed the walk test and 63.1% completed the health assessment. Median age of participants was 54 years, 25% were over 65 years, 58% were female, 89.2% White, and 76.1% were living with a chronic health condition. Participants spanned 27 states. This early phase of the 6th Vital Sign study demonstrates the feasibility of designing and disseminating a smartphone-based app to assess population health.