Enhanced echo intensity of skeletal muscle is associated with poor physical function in hemodialysis patients: a cross-sectional study

Background Patients on hemodialysis often suffer from reduced muscle strength and exercise capacity due to the decreased quantity and quality of muscle. Cumulative studies showed ultrasound echo intensity (EI) had great potential in evaluating muscle quality. The objective of this study was to evaluate the relationship between EI of skeletal muscle and physical function of patients on maintenance hemodialysis. Methods Cross-sectional area (CSA) and mean EI of the right rectus femoris were measured by ultrasound to evaluate the quantity and quality of the muscle, respectively. Physical function was measured by handgrip strength (HGS), gait speed, sit-to-stand 60 s (STS-60) test, and instrumental activities of daily living (IADL) scale. Results A total of 107 patients on hemodialysis were included, with women accounting for 37.3% (n = 40), and a mean age of 53.53 +/- 12.52 years. Among the patients on hemodialysis, EI was moderately and negatively correlated with HGS (r = - 0.467, P < 0.001), gait speed (r = - 0.285, P = 0.003), and STS-60 (r = - 0.313, P = 0.001). Multiple regression analyses adjusted for CSA showed that the enhanced EI of patients on hemodialysis remained associated with worse HGS (beta = - 0.207, P = 0.047), lower gait speed (beta = - 0.002, P = 0.001), less STS-60 (beta = - 0.136, P = 0.049), and a higher likelihood of dependency in IADL (Odds Ratio: 1.070, 95% CI: [1.033-1.111], P = 0.001). Conclusions In patients on hemodialysis, enhanced EI in the skeletal muscle measured via ultrasound was correlated with poor physical performance. The combined muscle quality and muscle quantity evaluation provide more information for assessing the level of physical function of the patients.