Association between morphological and mechanical properties of lower limb muscles and metabolic syndrome in type 2 diabetes

Metabolic syndrome (MS), a group of metabolic disorders including obesity, elevated blood pressure, abnormal blood lipid and blood glucose, is closely related to insulin resistance. Skeletal muscle is one of the important target organs of insulin, and is closely related to glucose uptake. In diabetic patients, weakened insulin signaling and elevated insulin resistance will accelerate muscle catabolism, while a high glucose state can also increase insulin resistance, thus leading to skeletal muscle atrophy and resulting in reduced skeletal muscle content or hardness. The study aims to explore the correlation between morphological and mechanical properties of lower limb muscles assessed by ultrasonic elastography and MS in populations with type 2 diabetes, and to evaluate its predictive value for MS. 516 patients with type 2 diabetes who were hospitalized in Zhongda Hospital Southeast University from December 2021 to August 2023 were included in this cross-sectional study, with a mean age of 61.87 ± 11.68 years. The median duration of diabetes in the general population was 8.0 years. Muscle thickness (MT) in MS group was significantly higher than that in non-MS group (P < 0.001), while shear wave velocity (SWV) and SWV/MT in MS group were significantly lower than those in non-MS group (P < 0.001). MT was a risk factor for MS, SWV and SWV/MT were protective factors for MS. SWV/MT in the straight position (SWV/MT_straight) had the highest predictive value with the optimum cut-off value of 1.96 100 s^-1, followed by SWV_straight with the optimum cut-off value of 3.57 m/s, which could indicate skeletal muscle ultrasound parameters were significantly correlated with MS in T2DM patients.Article Highlights 1. It is the first study to evaluate the correlation between the morphological and mechanical parameters of lower limb muscles measured by skeletal muscle ultrasound and metabolic syndrome in type 2 diabetes. 2. It is also the first study to use SWV/MT to comprehensively evaluate the morphological and mechanical properties of lower limb muscles.