Correlation of phase angle with sarcopenia and its diagnostic value in elderly men with cancer

The aims of this study was to investigate the association of phase angle (PA) with sarcopenia and its components and to evaluate the effectiveness of PA in sarcopenia diagnosis in older men (>65 y of age) with cancer. The study included older men with non–small cell lung cancer and digestive tract cancer who were hospitalized in the past 3 y. General characteristics such as age, body mass index, and tumor stage were gathered. Mid-upper arm muscle circumstance, calf circumstance, and handgrip strength (HGS) were measured. PA and appendicular skeletal muscle mass were examined by bioelectrical impedance analysis. According to the diagnostic criteria of the 2019 consensus of Asian Sarcopenia Working Group, the patients were divided into two groups: non-sarcopenia and sarcopenia. The study included 445 patients with a 22.2% prevalence of sarcopenia. PA was different between the non-sarcopenia and sarcopenia groups (5.02° versus 4.18°; P < 0.001). Pearson correlation showed that PA was related to diagnostic and confounding factors of sarcopenia. After adjusting for all potential confounding factors, multiple linear regression analysis showed diagnostic components of sarcopenia (HGS and skeletal muscle mass index [SMI]) could predict 25.3% of PA variation and logistic regression analysis showed PA (odds ratio, 0.309; P < 0.001) were related to sarcopenia. Then receiver operating characteristic curve showed the cutoff value of 4.25° with area under the curve of 0.785 for PA. PA is related to diagnostic components of sarcopenia, HGS and SMI. PA can be useful in the diagnosis of sarcopenia in older male patients with cancer. The cutoff value proposed in this study was 4.25°.