Research Article: Differential predictive value of phase angle for malnutrition and physical impairment in respiratory patients: the moderating role of sarcopenia
Abstract:
Phase angle (PhA) is a vital indicator of nutritional and physical performance, yet its utility may vary across different clinical phenotypes. This study aimed to determine the associations between PhA, malnutrition, and physical performance, and to evaluate whether these relationships are contingent upon sarcopenia status.
This study enrolled patients from the Department of Respiratory Medicine from March to September 2025. PhA was assessed using bioelectrical impedance analysis. Malnutrition and sarcopenia were diagnosed based on the Global Leadership Initiative on Malnutrition criteria and the Asian Working Group for Sarcopenia 2025, respectively. Physical performance was evaluated using the Short Physical Performance Battery score. The association between PhA and clinical outcomes, and potential moderating effect of sarcopenia, were analyzed using multivariable regression and interaction analysis.
A total of 235 patients were analyzed (mean PhA: 4.51?±?0.9°), including 114 with sarcopenia. Prevalence of malnutrition and impaired physical performance was 43.4 and 40.9%, respectively. After adjusting for potential confounders, interaction analysis revealed that the association between PhA and malnutrition was significantly modulated by the presence of sarcopenia ( P interaction =?0.035). Subgroup analysis revealed that a significant decrease in PhA was associated with an increased risk of malnutrition in the sarcopenia group (OR?=?3.11, 95% CI: 1.52–6.33, p <?0.001), whereas no such association was observed in the non-sarcopenia group (OR?=?1.35, 95% CI: 0.52–3.52, p =?0.52). Conversely, each 1°PhA decrease was associated with an increased risk of impaired physical function (OR?=?4.59, 95% CI: 2.44–8.62, p <?0.001), regardless of sarcopenia status ( P interaction =?0.561).
The association between PhA and malnutrition is primarily driven and amplified by sarcopenia. However, PhA remains a robust, independent predictor of impaired physical performance across all respiratory patients regardless of sarcopenia status.
Introduction:
Phase angle (PhA) is a vital indicator of nutritional and physical performance, yet its utility may vary across different clinical phenotypes. This study aimed to determine the associations between PhA, malnutrition, and physical performance, and to evaluate whether these relationships are contingent upon sarcopenia status.
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