Social Frailty Predicts Incident Disability and Mortality Among Community-Dwelling Japanese Older Adults

Objective To determine the prevalence of social frailty and its relation to incident disability and mortality in community-dwelling Japanese older adults. Design Prospective cohort study. Setting and Participants 6603 community-dwelling adults aged 65 years and older who were living independently in a city in Shiga prefecture in 2011. Outcomes The outcomes were incident disability and mortality. We defined incident disability using new long-term care insurance (LTCI) service requirement certifications, and the follow-up period was 6 years after the mailed survey. Measurements The 4-item social frailty screening questionnaire was developed and included general resources, social resources, social behavior, and fulfillment of basic social needs. We categorized the respondents into 3 groups based on the level of social frailty. Additionally, we assessed physical/psychological frailty by the frailty screening index and other demographic variables. Results The prevalences of social frailty, social prefrailty, and social robust were 18.0%, 32.1%, and 50.0%, respectively. During the 6-year follow-up period, 28.1% of those with social robust, 36.9% of those with social prefrailty, and 48.5% of those with social frailty died or experienced incident disability. Those with social prefrailty [adjusted hazard ratio (HR) 1.28, 95% confidence interval (CI) 1.16-1.41] and social frailty (adjusted HR 1.71, 95% CI 1.54-1.90) had significantly elevated risks for incident disability and mortality based on multivariate analyses that used social robust as the reference. Furthermore, the combination of social frailty and physical/psychological frailty is more likely to result in incident disability and mortality compared to social frailty or physical/psychological frailty alone. Conclusions/Implications Community-dwelling older adults with both social frailty and physical/psychological frailty are at higher risk of death or disability over 6 years than are older adults with only one type of frailty or no frailty. Screening and preventive measures for social frailty are suggested for healthy aging.