Impact of physical frailty on disability in community-dwelling older adults: a prospective cohort study

OBJECTIVE To examine the relationship between physical frailty and risk of disability, and to identify the component(s) of frailty with the most impact on disability in community-dwelling older adults. DESIGN Prospective cohort study. SETTING A Japanese community. PARTICIPANTS 4341 older adults aged ≥65 living in the community participated in a baseline assessment from 2011 to 2012 and were followed for 2 years. MAIN OUTCOME MEASURES Care-needs certification in the national long-term care insurance (LTCI) system of Japan, type of physical frailty (robust, prefrail, frail) and subitems (slowness, weakness, exhaustion, low activity, weight loss), adjusted for several potential confounders such as demographic characteristics, analysed with Kaplan-Meier survival curves for incidence of disability by frailty phenotype. RESULTS During the 2-year follow-up period, 168 participants (3.9%) began using the LTCI system for incidence of disability. Participants classified as frail (HR 4.65, 95% CI 2.63 to 8.22) or prefrail (2.52, 1.56 to 4.07) at the baseline assessment had an increased risk of disability incidence compared with robust participants. Analyses for subitems of frailty showed that slowness (2.32, 1.62 to 3.33), weakness (1.90, 1.35 to 2.68) and weight loss (1.61, 1.13 to 2.31) were related to increased risk of disability incidence. In stratified analyses, participants who were classified as frail and who had lower cognitive function had the highest percentage (30.3%) of disability incidence during the 2 years after baseline assessment. CONCLUSIONS Physical frailty, even being prefrail, had a strong impact on the risk of future disability. Some components of frailty, such as slowness, weakness and weight loss, are strongly associated with incident disability in community-dwelling older adults.