Linking probable respiratory sarcopenia to frailty in older adults: A cross-sectional and longitudinal analysis

Frailty is a common geriatric syndrome linked to disability and mortality. Respiratory sarcopenia (RS), recently conceptualized as concurrent decline in muscle and respiratory function, may contribute to frailty, but evidence is scarce. We analyzed data from the nationally representative China Health and Retirement Longitudinal Study. Probable RS was defined, following the 2023 consensus, as low peak expiratory flow rate (PEFR) plus low appendicular skeletal muscle (ASM) mass. Frailty was assessed using the Fried frailty phenotype. Cross-sectional associations were assessed using logistic regression among 2107 adults aged ≥60 years in 2011; incident frailty was assessed using Cox proportional hazards models among 1599 participants followed through 2015. In 2011, the frailty prevalence was 8.4%, and probable RS affected 28.0%. Cross-sectionally, low ASM mass (odds ratio [OR] = 2.17; 95% confidence interval [CI] = 1.55-3.05; P < .001), low PEFR (OR = 2.23; 95% CI = 1.31-3.79; P = .003), and probable RS (OR = 2.53; 95% CI = 1.81-3.52; P < .001) were all linked to frailty. Over 5746 person-years, the frailty incidence was 13.9 per 1000 person-years. Probable RS predicted incident frailty (hazard ratio [HR] = 3.26; 95% CI = 2.08-5.10; P < .001), as did low ASM mass (HR = 3.78; 95% CI = 2.37-6.04; P < .001), whereas low PEFR alone (HR = 1.47; 95% CI = 0.77-2.79; P = .243) was not statistically significant. Probable RS was associated with incident frailty in Chinese older adults. Its reliance on simple, low-cost measures highlights potential utility for early risk stratification, and interventions addressing both muscle and respiratory function may help delay frailty progression.