A recent Stanford University study compared the effectiveness of the Apple Watch in assessing frailty in cardiovascular patients, in comparison with an in-clinic six-minute walk test (6MWT). The study enrolled 110 patients who were scheduled for vascular or cardiac procedures at a Veterans Administration facility, supplied them with an iPhone and Apple Watch running the VascTrack research application, and followed them for six months. Periodic in-clinic 6MWT results were compared with in-home 6MWT performed using the app, and passive step information collected by the Apple Watch. The tests assessed frailty, defined as walking fewer than 300 meters on an in-clinic 6MWT. The Apple Watch was nearly as effective in assessing frailty via the 6MWT in the home setting as in the clinic setting (83% sensitive and 60% specific in assessing frailty in the home setting, versus 90% sensitive and 85% sensitivity in the clinic setting). Passive data collected at home was nearly as accurate as the 6MWT in-home assessment.