Association between frailty and subsequent disability trajectories among older adults: a growth curve longitudinal analysis from the Survey of Health, Ageing and Retirement in Europe (2004-19).

Frailty is associated with adverse health outcomes in ageing populations, yet its long-term effect on the development of disability is not well defined. The study examines to what extent frailty affects disability trajectories over 15 years in older adults aged 50+. Using seven waves of data from the Survey of Health, Ageing and Retirement in Europe (SHARE), the study estimates the effect of baseline frailty on subsequent disability trajectories by multilevel growth curve models. The sample included 94 360 individuals from 28 European countries. Baseline frailty was assessed at baseline, using the sex-specific SHARE-Frailty-Instrument (SHARE-FI), including weight loss, exhaustion, muscle weakness, slowness, and low physical activity. Disability outcomes were the sum score of limitations in activities of daily living (ADL) and Instrumental ADL (IADL). Analyses were stratified by sex. Over 15 years, baseline frailty score was positively associated with disability trajectories in men [βADL = 0.074, 95% confidence interval (CI) = 0.064; P = .083; βIADL = 0.094, 95% CI = 0.080; P = 0.107] and women (βADL = 0.097, 95% CI = 0.089; P = .105; βIADL = 0.108, 95% CI = 0.097; P = .118). Frail participants showed higher ADL and IADL disability levels, independent of baseline disability, compared with prefrail and robust participants across all age groups. Overall, participants displayed higher levels of IADL disability than ADL disability. Study findings indicate the importance of early frailty assessment using the SHARE-FI in individuals 50 and older as it provides valuable insight into future disability outcomes.