Sarcopenic obesity versus sarcopenia alone with the use of probable sarcopenia definition for sarcopenia: Associations with frailty and physical performance

Ageing brings alterations in body composition, as skeletal muscle gradually declines and accumulation of adipose tissue accompanies it. Although sarcopenia (S) and obesity (O) were separately reported to be associated with frailty and poor physical performance, whether they bring more detrimental or favorable effect when they coexist (i.e. sarcopenic obesity; SO) is an issue needs clarification. We aimed to study the associations of SO and S alone with frailty and poor physical performance, by using probable S definition.This was a retrospective, cross-sectional study including community dwelling older adults who were ≥60 years old and admitted to the outpatient clinic of a tertiary hospital between 2012 and 2020. We measured handgrip strength via hand dynamometer and defined decreased muscle strength as probable S. We performed bioimpedance analysis to evaluate body composition and used fat percentile method to define obesity. We assessed nutritional status via Mini-Nutritional Assessment-Short Form, frailty via FRAIL scale, and physical performance via Timed Up and Go (TUG) test. We examined the associations of four body phenotypes, i.e. non-S non-O, SO, S alone and O alone with frailty and impaired TUG in univariate and multivariate analyses (Model 1). We further performed a head to head analysis of SO vs S to see if one of them was associated more with frailty and impaired TUG (Model 2).There were 1366 older adults included in the study (mean age: 74.6 ± 6.9; 68.3% female). The prevalences of non-S non-O, S alone, SO and O alone were 53.5, 7.5, 2.8 and 36.2%, respectively. Multivariate analysis adjusted for age, gender and nutritional status revealed that both SO and S alone were independently associated with frailty and impaired TUG, with SO demonstrating lower odds than S alone (OR = 5.9 and 6.05 for frailty, and 3.9 and 4.4 for TUG, respectively). Head-to-head comparison between SO and S alone in Model 2 showed that two groups did not demonstrate significant difference in terms of the frailty and impaired TUG risk.Although SO and S groups demonstrated similar risks, obesity accompanying sarcopenia might show a favorable trend in terms of frailty and poor physical performance, compared to sarcopenia alone. Longitudinal studies are needed to reveal whether an obesity paradox exists for frailty and physical performance in older adults.