Ultrasound-Derived Quadriceps Muscle Measurements Are Independently Associated With Physical Frailty in Patients Undergoing Hemodialysis

OBJECTIVE: Patients undergoing hemodialysis (HD) frequently experience functional decline and a high prevalence of physical frailty. Ultrasound-derived muscle assessment enables objective bedside quantification of muscle mass and composition, while circulating biomarkers may provide additional insight into muscle-related physiology. This study examined the association of quadriceps muscle ultrasound measurements and serum biomarkers with physical frailty in HD patients. DESIGN AND METHODS: This is a subanalysis of a cohort study comprising adult patients on maintenance HD. Physical frailty was classified using the physical frailty phenotype (≥3 criteria). Blood samples were collected to measure serum concentrations of heat shock protein 72 and C-terminal agrin fragment using enzyme-linked immunosorbent assay kits. After the HD session, B-mode ultrasound was performed to assess thickness and echogenicity of the rectus femoris and vastus intermedius (RFVI), and vastus lateralis and vastus intermedius (VLVI). RESULTS: Seventy-six patients were included, 45% with frailty. Multivariate logistic regression model adjusted for body mass index, age, and HD vintage, greater muscle thickness was associated with lower odds of frailty [RFVI (odds ratio [OR]: 0.340; 95% confidence interval [CI]: 0.150-0.774; P = .010); VLVI (OR: 0.244; 95% CI: 0.093-0.642; P = .004)], while higher muscle echogenicity was associated with higher odds [(RFVI (OR: 1.048; 95% CI: 1.007-1.090; P = .021); VLVI (OR: 1.108; 95% CI: 1.043-1.176; P = .001). No significant associations were found between C-terminal agrin fragment and heat shock protein 72 with frailty. CONCLUSION: Quadriceps muscle measurements were associated with physical frailty, reinforcing their use as a practical and clinically relevant tool for muscle assessment in hemodialysis patients.