A Prognostic Model for COPD Complicated With Sarcopenic Obesity Based on Bioelectrical Impedance Phase Angle Technology

The primary objective of this study is to use multi-segment bioelectrical impedance phase angle technology to explore the diagnosis, impact, and prognostic factors of COPD complicated with sarcopenic obesity. The study aims to clarify the diagnostic value and efficacy of body composition analysis in specific populations, analyze the relationship between phase angle and COPD severity as well as quality of life, investigate its predictive role for adverse outcomes, and reveal the effects of inflammation and metabolic disorders in sarcopenic obesity. The goal is to provide a basis for early screening and precise intervention to improve patient prognosis.

Inclusion criteria

• Age over 65 years;
• Ability to complete physical activity assessments and pulmonary function tests;
• Complete medical records, willingness to adhere to follow-up arrangements, and provision of adverse event reports via telephone or outpatient visits, with signed informed consent;
• COPD diagnosis based on the American Thoracic Society (ATS)/European Respiratory Society (ERS) GOLD definition, with a post-bronchodilator FEV1/FVC ratio < 0.70, current or former smokers with a smoking history of ≥10 pack-years.

Exclusion criteria

• Severe cognitive impairment or hand deformities (e.g., rheumatoid arthritis) preventing body composition measurements;
• Incomplete clinical or follow-up data or unwillingness/inability to undergo regular follow-up;
• Severe systemic edema;
• Presence of cardiac pacemakers or significant metal implants that may interfere with measurements;
• Voluntary withdrawal for any reason, including loss to follow-up.