Joint trajectories of physical frailty and social frailty and associations with adverse outcomes: A prospective cohort study

We examined joint trajectories of physical frailty and social frailty as well as their associations with adverse outcomes. We conducted a prospective cohort study by using five waves of national data from China Health and Retirement Longitudinal Study (CHARLS 2011-2020), involving 4531 participants aged ≥60 years. We identified 4-year trajectories at three examinations from 2011 to 2015 using parallel process latent class growth analysis. Adverse outcomes were obtained from 2015 to 2020 across two subsequent waves. We calculated hazard ratios (HR) using Cox proportional hazard models. We also conducted analyses by gender. Three joint trajectories were identified, including persistent absence of physical and social frailty (58.5%), no physical frailty but social frailty (28.1%), and persistent combination of physical and social frailty (13.4%). Compared with persistent absence of physical and social frailty, no physical frailty but social frailty and persistent combination of physical and social frailty were associated with higher risk of instrumental activities of daily living (IADL) disability (HR=1.182-2.020, 95% CI: 1.014-2.416) and all-cause mortality (HR=1.440-2.486, 95% CI: 1.211-3.009). The persistent combination of physical and social frailty was also associated with ADL disability (HR=2.412, 95% CI: 1.999-2.911) and falls (HR=1.410, 95% CI: 1.196-1.662). Gender differences were observed in relationships between joint trajectories and adverse outcomes. Community-dwelling older adults exhibit distinct joint trajectories and those with persistent combination of physical and social frailty experience greatest risk of incident adverse outcomes. Clinical and public health measures targeting physical or social frailty should account for both and be gender-specific.