Measuring shear wave velocity: a potential tool for early detection of muscle decline in middle aged and older adults with type 2 diabetes

Assessing muscular alterations is crucial for clinical monitoring of type 2 diabetes (T2D), yet studies evaluating assessment approaches remain limited. We aimed to evaluate the biceps brachii muscle (BBM) using conventional ultrasound and shear wave velocity (SWV) in individuals with and without T2D, exploring correlations between ultrasonic indicators and clinical parameters. Seventy-five T2D patients and forty-one healthy controls (all aged > 45 years) were recruited. The BBM was assessed by ultrasound derived thickness, cross-sectional area (CSA), and SWV at different elbow joint angles (full extension and 90° flexion). Blood tests and diabetes-related comorbidities were recorded for T2D patients. Compared with healthy controls, T2D patients exhibited no differences in grip strength, BBM thickness, or CSA. However, SWV at full extension (SWVfull extension) and the change in SWV between angles (ΔSWVfull extension−90°) were significantly elevated in T2D patients (both p < 0.001). Multivariate analysis identified T2D presence as independently associated with increased SWVfull extension (OR 6.39; 95% CI 2.42–16.83) and decreased grip strength (OR 0.93; 95% CI 0.87–0.99). The T2D patients were then stratified into short diabetes duration group (≤ 10 years) and long diabetes duration group (>10 years). The linear mixed model analysis of SWV at different elbow angles showed that the main effects of patient group, acquisition angle, as well as their interaction, were all statistically significant. The patients with short diabetes duration (≤ 10 years) showed significantly increased BBM thickness, CSA, SWVfull extension and ΔSWVfull extension−90° versus controls, despite comparable grip strength. Notably, patients with long diabetes duration (> 10 years) had significantly reduced grip strength (p = 0.002), thickness (p < 0.001), CSA (p < 0.001), while increased ΔSWVfull extension−90° (p = 0.010) compared with patients with short duration. In addition, Correlation analyses revealed BBM thickness and CSA positively correlated with grip strength but inversely correlated with diabetes duration and HOMA-IR. Conversely, SWVfull extension and ΔSWVfull extension−90° positively correlated with diabetes duration and HbA1c. SWV measurements detected early BBM alterations in middle-aged and older adults with T2D. Patients exhibited significantly higher muscle stiffness than controls, despite equivalent grip strength, thickness, and CSA. Critically, these SWV abnormalities emerged in early-stage T2D (duration ≤ 10 years), preceding measurable declines in grip strength. These findings suggest SWV might be used as a potential tool for identifying incipient muscle decline for T2D patients.