Prevalence, associated factors, and bioelectrical impedance phase angle measurement for sarcopenia in patients undergoing cardiac rehabilitation

This study aimed to determine the prevalence and associated risk factors of sarcopenia among patients with cardiovascular diseases (CVD) undergoing cardiac rehabilitation (CR) and to evaluate the diagnostic accuracy of phase angle (PhA) in identifying sarcopenia. This cross-sectional study included 100 patients with ischemic heart disease undergoing outpatient CR. Sarcopenia was diagnosed based on the criteria of the Asian Working Group for Sarcopenia 2019, which utilized measurements of muscle mass, handgrip strength, and gait speed. PhA was measured using bioelectrical impedance analysis. Multivariable logistic regression was used to identify factors associated with sarcopenia, and receiver operating characteristic (ROC) curve analysis was conducted to evaluate the diagnostic performance of PhA. The prevalence of sarcopenia in the study population was 35%, with 23% classified as having severe sarcopenia. Female sex [adjusted odds ratio (aOR) 5.9, P = 0.004] and lower BMI (aOR 0.71, P = 0.005) were significantly associated with sarcopenia. Mean PhA values were significantly lower in patients with sarcopenia compared to those without (3.61 vs. 4.47 °, P < 0.001). ROC curve analysis demonstrated good diagnostic accuracy of PhA for identifying sarcopenia, with an area under the curve of 0.83 (95% confidence intervals: 0.75-0.91). The optimal PhA cutoff value to distinguish sarcopenia was 4.01 °, yielding both sensitivity and specificity of 80%. Sarcopenia was prevalent among CVD patients undergoing CR, with female gender and lower BMI as significant risk factors. PhA demonstrated high diagnostic accuracy for detecting sarcopenia and may serve as a useful, noninvasive tool in clinical settings.