Validation of Phase Angle Cutoff Values Derived From Bioelectrical Impedance Analysis for Sarcopenia Screening in Community-Dwelling Older Korean Adults

Objectives Sarcopenia, characterized by progressive loss of skeletal muscle mass and function, poses a significant risk to the aging population. This study aimed to validate the efficacy of phase angle (PhA) derived from bioelectrical impedance analysis (BIA) as a screening tool for sarcopenia in community-dwelling middle-aged and older Korean adults. Design The study employed a cross-sectional design to assess the association between PhA and sarcopenia. Setting and Participants The study was conducted in Busan, South Korea, and included 699 community-dwelling participants aged 50 years and older using a purposive sampling method. Methods Sarcopenia was classified based on the Asian Working Group for Sarcopenia 2019 criteria. Participants completed the SARC-F questionnaire, a self-assessment tool for sarcopenia risk. BIA was used to measure PhA, a parameter reflecting body composition. Statistical analyses, including analysis of variance, χ² tests, and receiver operating characteristic curve analysis, were used to compare PhA values between groups and determine optimal cutoff points. Results Among 699 participants (78.5% female, mean age 75.7 years), 97 had sarcopenia and 77 had severe sarcopenia. Mean PhA values were lower in those with sarcopenia (men: 5.1, women: 4.6) and severe sarcopenia (men: 4.8, women: 4.3) compared with those without (men: 6.0, women: 5.2). PhA demonstrated superior screening capability for sarcopenia compared with SARC-F scores in both men and women. Optimal PhA cutoff values for detecting severe sarcopenia were 5.35 for men [area under the curve (AUC): 0.767] and 4.75 for women (AUC: 0.816), indicating strong potential for clinical application. Conclusions and Implications The established PhA cutoff values can be integrated into routine health assessments, enabling early detection and targeted interventions that could improve the quality of life of this population.