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 (HSP72) and C-terminal agrin fragment (CAF) using ELISA 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 (OR: 0.340; 95%CI: 0.150-0.774; p = 0.010); VLVI (OR: 0.244; 95% CI: 0.093-0.642; p = 0.004)], while higher muscle echogenicity was associated with higher odds [(RFVI (OR: 1.048; 95% CI: 1.007-1.090; p = 0.021); VLVI (OR: 1.108; 95% CI: 1.043-1.176; p = 0.001). No significant associations were found between CAF and Hsp72 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.