Serum Myonectin Levels Are Positively Associated With Physical Function and Lower Frailty‐Related Limitation in Maintenance Hemodialysis Patients: A Cross‐Sectional Study

BACKGROUND: Maintenance hemodialysis (MHD) patients frequently suffer from frailty, characterized by reduced physical function and poor prognosis. Myokines, such as myonectin, secreted by muscle, are emerging regulators of systemic health. This study investigated the relationship between serum myonectin, adipokines (adiponectin, omentin), and objective measures of physical function in MHD patients, excluding previously planned cardiac data. METHODS: This cross-sectional study included 23 MHD outpatients. We assessed physical function using the Short Physical Performance Battery (SPPB) score and the 5-Sit-to-Stand Test (5-SST). We also measured body composition, physical activity (accelerometer-derived step count), and serum concentrations of myonectin, adiponectin, and omentin. Correlation analysis and comparison between high (≧ median) and low (< median) myonectin groups were performed. RESULTS: Serum myonectin was positively correlated with Body Mass Index (BMI) and the SPPB score. No significant correlations were observed between myonectin and other physical function or physical activity indicators. Furthermore, the high myonectin group showed significantly better performance compared to the low group, completing the 5-SST in a shorter time and achieving a higher SPPB score. Adiponectin showed significant inverse correlations with BMI, muscle mass, and fat mass. CONCLUSION: Serum myonectin levels are positively associated with superior physical function (SPPB) and faster lower-extremity performance (5-SST) in MHD patients. Myonectin may serve as a simple, novel biomarker to identify MHD patients with better preserved functional capacity and potentially less frailty-related limitation. These findings underscore the critical role of muscle health in maintaining function in this vulnerable population.