ORIGINAL RESEARCH article
Front. Med.
Sec. Pulmonary Medicine
Lower Bioelectrical impedance phase angle is associated with COPD and is a marker for increased risks in elderly COPD patients
Provisionally accepted
- Peking University, Beijing, China
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The phase angle (PhA), derived from bioelectrical impedance analysis (BIA), serves as an indicator of cellular health and body composition. While associated with muscle strength and exercise capacity in various conditions, its clinical relevance in chronic obstructive pulmonary disease (COPD) requires further characterization. This study aimed to evaluate the relationship between PhA, muscle strength, and physical function in individuals with COPD. Methods Between March 2021 and March 2024, 112 male patients with COPD and 20 male healthy controls were enrolled in this cross-sectional study. Assessments included pulmonary function, body composition via BIA, handgrip strength, knee extension strength, walking speed, and other clinical indicators. Relationships were analyzed using multivariable linear and LASSO regression models. Results PhA values were significantly lower in COPD patients than in healthy controls. Stratification of COPD patients by PhA revealed that a lower PhA was associated with progressively worse muscle strength, exercise capacity, and other clinical markers. Multivariable linear regression analyses demonstrated that a lower PhA was independently associated with slower walking speed (β = 0.061, p < 0.001) and reduced knee extension strength (β = 1.15, p = 0.002). Furthermore, PhA was selected as a key predictor in a prognostic model for severe physical impairment derived from LASSO regression. Conclusion In this cross-sectional study, a lower PhA is independently associated with muscle weakness and impaired physical performance in men with COPD. These findings suggest that PhA may serve as a useful biomarker for assessing nutritional and functional status in this population. However, the cross-sectional design precludes causal inference, and the diagnostic utility of PhA for COPD itself is not established.
Keywords: PHA, COPD, Grip strength, Knee extension strength, BIA
Received: 11 Sep 2025; Accepted: 12 Nov 2025.
Copyright: © 2025 Fan, Qian, Xu, Zhang, Wu and Wang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Xiaoyun Fan, fanxiaoyun201822@163.com
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