Objective To systematic investigate whether phase angle of bioelectrical impedance is associated with the functionality, severity, and prognosis of individuals afflicted with chronic obstructive pulmonary disease (COPD). Methods Relevant literature from the PubMed, Embase, Web of Science, Scopus, CNKI, and WanFang databases was retrieved, and literature screening and data extraction in accordance with standardized methods were conducted. Literature quality was assessed by utilizing Mixed Methods Appraisal Tool. Subsequently, data pertaining to the results was extracted for summarization and induction, and descriptive analyzed through qualitative synthesis. Results A total of 11 studies, encompassing 2189 subjects, were included in this review, and the overall quality of the literature was deemed relatively high. Of these studies, three examined the correlation between phase angle and the severity of COPD, eight studies examined the correlation between phase angle and pulmonary and physical function in COPD, and seven studies reported the association between phase angle and adverse outcomes such as hospitalization time, nutritional risk, acute exacerbation and mortality in COPD. The collective findings suggestted that reduced levels of phase angle are linked to severe illness, diminished function, and unfavorable prognosis among individuals with COPD. Phase angle emerged as an independent predictor of lung function, physical exercise endurance, acute exacerbation and mortality in COPD patients. Conclusion The phase angle level of COPD patients is associated with their disease severity, function, and prognosis, and is an potential available indicator for clinical management of COPD patients.
Objective To investigate the mediating effect of phase angle between muscle strength and muscle function in maintenance hemodialysis (MHD) patients, aiming to provide a reference basis for clinical improvement of muscle strength and muscle function in MHD patients. Methods Random sampling was used to collect patients undergoing outpatient MHD in the Wenjiang Hemodialysis Room of the Department of Nephrology, West China Hospital, Sichuan University between September and December 2023 as the subjects of this study. Muscle strength was assessed by handgrip strength, muscle function was assessed by Short Physical Performance Battery (SPPB), and phase angle was measured by bioelectrical impedance analysis. The mediating effect of phase angle between muscle strength and muscle function was analyzed. Results A total of 239 MHD patients were included, including 125 males (52.3%) and 114 females (47.7%). The mean phase angle of MHD patients was (5.77±1.17)°, 89 patients (37.2%) showed decreased muscle strength, and 109 patients (45.6%) showed muscle hypoplasia. Spearman’s correlation analyses showed that phase angle was significantly and positively correlated with both handgrip strength and SPPB in MHD patients (P<0.001). The results of mediation effect analysis showed that handgrip strength was able to positively predict phase angle (β=0.535, P<0.001); handgrip strength was able to positively predict SPPB (β=0.481, P<0.001); phase angle was able to positively predict SPPB (β=0.296, P<0.001); and when both handgrip strength and phase angle entered in the regression equation, both handgrip strength (β=0.392, P<0.001) and phase angle (β=0.165, P<0.05) could positively predict SPPB. Phase angle in MHD patients partially mediated the association between muscle strength and muscle function, with the mediating effect accounting for 32.5% of the total effect. Conclusions There is a close relationship between phase angle, muscle strength and muscle function in MHD patients, and muscle strength can affect muscle function directly or indirectly through phase angle. Medical professionals should pay attention to the muscle function of MHD patients and further improve their muscle function by improving their phase angle and muscle strength.
