Independent and combined effects of sarcopenia and physical frailty on the incident functional disabilities in community-dwelling older adults: A 6-year prospective study.

BACKGROUND: Sarcopenia and physical frailty are interrelated conditions that frequently co-occur in older adults; however, it remains unclear whether each condition independently or in combination contributes to the risk of functional disabilities. We aimed to examine independent and combined associations of sarcopenia and physical frailty with functional disabilities among community-dwelling older adults over a 6-year follow-up period. METHODS: In total, 2067 older adults were enrolled in Korean Frailty and Aging Cohort Study. Functional disabilities-activities of daily living (ADL) disability, instrumental ADL (IADL) disabilities, falls, and severe mobility limitation-were assessed biennially over 6 years. Sarcopenia and frailty were defined by Asian Working Group for Sarcopenia 2025 criteria and the Fried frailty phenotype, respectively. Competing risk regression models estimated the 6-year incidence of functional disabilities across groups. RESULTS: IADL disability risk was higher in both frailty only (sub-distribution hazard ratio [sHR] 1.70, 95% CI 1.20-2.42) and coexistent frailty and sarcopenia (sHR 1.58, 95% CI 1.06-2.36). Frailty only was associated with increased risks of ADL disability (sHR 1.54, 95% CI 1.03-2.32), falls (sHR 1.60, 95% CI 1.10-2.33), and severe mobility limitation (sHR 1.92, 95% CI 1.14-3.24); however, coexistent frailty and sarcopenia group was not associated with these outcomes. Similarly, sarcopenia alone showed no significant association with any outcome. CONCLUSIONS: Both frailty alone and coexisting frailty and sarcopenia can increase the IADL disability risk, whereas ADL disability, falls, and severe mobility limitation were associated primarily with frailty alone. These findings underscore clinical importance of prioritizing frailty assessment for detecting functional disability in older adults.