Physical Indicators and Cutoff Values Associated with Improvement in Sarcopenia in Older Adults Undergoing Rehabilitation

IntroductionSarcopenia is a skeletal muscle disorder characterized by a decline in both skeletal muscle mass and function 1,2 .Consequently, it is associated with adverse health outcomes, such as falls and fractures 3,4 , functional decline 4,5 , long-term care dependency 6 , and mortality 4,[7][8][9][10] .Recent studies have shown that the prevalence of sarcopenia is particularly high in rehabilitation settings 11 , which is linked to delayed recovery in independence in activities of daily living (ADLs) and poorer prognosis [12][13][14] .Yet many of these studies focus on specific disease populations, such as stroke patients, or relatively homogeneous clinical cohorts.Conversely, improvement in sarcopenia (IS) during hospitalization has been associated with better ADL outcomes and increased rates of discharge to home 15 , underscoring the clinical importance of addressing sarcopenia in the rehabilitation settings.Despite its relevance, although previous studies have examined sarcopenia-related physical indicators and functional outcomes in rehabilitation settings, the physical indicators associated with IS-defined as a change in sarcopenia diagnostic status among diverse Abstract Objectives: This study aimed to determine baseline physical indicators and their cutoff values associated with improvement in sarcopenia (IS) in older individuals undergoing rehabilitation.Methods: We retrospectively reviewed 343 older individuals with sarcopenia (median age = 81 years) admitted to a rehabilitation hospital between January 2020 and September 2023 after discharge from acute care hospitals.Sarcopenia was diagnosed using the 2019 Asian Working Group for Sarcopenia criteria; IS was defined as no longer meeting the diagnostic criteria at discharge.Baseline assessments included handgrip strength (HGS), gait speed (GS), skeletal muscle mass index (SMI), and the Short Physical Performance Battery.We used sex-wise multivariate logistic regression analyses to identify factors associated with IS and receiver operating characteristic curve analyses to determine cutoff values.Results: IS was seen in 16 males (17%) and 46 females (18%).Associated indicators were GS (p = 0.019; cutoff: 0.78 m/s) and SMI (p = 0.004; cutoff: 6.7 kg/m 2 ) in males, and HGS (p < 0.001; cutoff: 15.0 kg) and SMI (p < 0.001; cutoff: 5.1 kg/m 2 ) in females.Conclusions: Baseline SMI, plus GS in males and HGS in females, was associated with IS.These cutoff values may help to characterize individuals with different likelihoods of diagnostic improvement.