Phase Angle and Functional Mobility in Sarcopenic Obesity

INTRODUCTION Sarcopenic obesity (SO) is characterized by the coexistence of excess adiposity and impaired muscle mass, strength, and function [1], with systemic inflammation and insulin resistance being among the pathogenic factors [2]. While quantitative bioelectrical impedance analysis (BIA) is part of SO diagnosis, raw BIA parameters like phase angle (PhA) remain largely unexplored in their ability to identify altered muscle mass and function [3] METHODS This cross-sectional study included individuals with obesity (BMI ≥ 30 kg/m2). Body composition was assessed via BIA; metabolic status was evaluated through baseline glucose and insulin, glycosylated hemoglobin, HOMA-IR, and 25-OH vitamin D, while inflammation status by C-reactive protein and erythrocyte sedimentation rate. Physical function was assessed via handgrip strength test, 5-repetition and 30-s sit-to-stand test, 6-minute walk test (6MWT), Timed Up and Go (TUG), and one-leg Stand Balance (OLSB). SO was diagnosed based on the EASO-ESPEN criteria (1). One-way ANCOVA and Spearman's rho (rs) were used to explore between-group differences and correlation between continuous variables, respectively, while controlling for the confounding effect of age. RESULTS A total of 72 subjects (73.6% female) were enrolled [age: 54.0 (45.8-61.5); BMI: 37.1 (33.5-41.8) kg/m2; median (IQR)]. Among these, n=27 (74.1% female) were affected by SO, while n= 45 (73.3% female) by obesity alone. The correlation between PhA and TUG approached the threshold of statistical significance (rs = -0.27, p = 0.068, whole sample). While no significant between-group differences emerged for metabolic status variables and inflammatory biomarkers (all p > 0.1), the SO group exhibited a medium-sized, significant reduction in left limb maximum OLSB time (Cohen’s d= -0.68, p = 0.043) compared to the obesity-only group. CONCLUSION PhA and TUG displayed a negatively correlation which, in light of its trend towards significance despite our small sample size, potentially reflects the value of PhA as an indicator of functional mobility. On the back of a moderate reduction in left limb maximum OLSB time observed in the SO group, future studies are warranted to integrate the use of raw BIA parameters with functional tests in the diagnostic framework of SO. REFERENCES [1 Donini LM , et al. Definition and Diagnostic Criteria for Sarcopenic Obesity: ESPEN and EASO Consensus Statement. Obes Facts 2022;15:321-35. https://doi.org/10.1159/000521241. [2] Choi KM. Sarcopenia and sarcopenic obesity. Korean J Intern Med 2016;31:1054-60. https://doi.org/10.3904/kjim.2016.193. [3] Cappellari GG, , et al. Sarcopenic obesity research perspectives outlined by the sarcopenic obesity global leadership initiative (SOGLI)-proceedings from the SOGLI consortium meeting in Rome, November 2022. Clin Nutr 2023;42:687-99. presentation: oral