Classification of the Frailty Status of Community-Dwelling Older Adults Using Physical Activity Data Collected through Consumer Activity Trackers

Backgrounds: Engaging in light activity, moderate-to-vigorous physical activity (MVPA), or sedentary behavior can influence the health status of older adults. The purpose of this study was to examine the relationship between frailty and the daily amount of physical activity, as measured by an activity tracker, and to identify frail older adults based on the tracker data. Methods: The participants were community-dwelling older adults (aged ³ 65 years) classified as frail or non-frail. Frailty was defined by the presence of three or more of the following: weight loss, exhaustion, low energy expenditure, slow gait speed, and weak grip strength. Physical activity was monitored using the activity tracker, and the daily durations of MVPA, light activity, and sedentary activity were measured over a 7-day period. Results: The duration of MVPA was significantly associated with frailty status (unadjusted odds ratio = .936, p = .018; adjusted odds ratio = .935, p = .039). There was no significant association between frailty and the duration of light or sedentary activity. However, classification and regression tree analysis generated cutoff points of £ 29.65 min/day and £ 156.93 min/day of MVPA and light activity, respectively, for determining frailty in older adults with an accuracy of 87.7%. Conclusions: Durations of MVPA and light activity, as measured using an activity tracker, differentiated frail and non-frail older adults. The classification and regression tree analysis yielded cutoff points that could inform recommendations regarding the daily amount of physical activity for older people.