Sarcopenia (SAR) has a high prevalence in patients with type 2 diabetes mellitus (T2DM) and is closely associated with body composition (BC), bone mineral density (BMD), and insulin resistance (IR). Data on elderly T2DM patients in Northwest China are still lacking.

This work was aimed at investigating the characteristics of body composition and bone density in T2DM patients with SAR, analyzing their independent influencing factors, and providing a basis for precise clinical prevention and treatment.

A total of 126 elderly T2DM patients were retrospectively enrolled and divided into a disease group (DG, n = 57) and a control group (CG, n = 69) based on the presence of SAR. Independent samples t-tests and χ2 tests were used to compare clinical indicators between the two groups. Multivariate logistic regression analysis was performed to screen for influencing factors of T2DM combined with SAR.

Compared with the CG, the DG showed significantly lower calf circumference (CC) (34.1 ± 3.3 cm vs. 38.4 ± 2.8 cm, p < 0.001), muscle mass (MM) (25.1 ± 4.7 kg vs. 32.3 ± 5.2 kg, p < 0.001), and hip BMD (0.81 ± 0.10 g/cm2 vs. 0.86 ± 0.08 g/cm2, p = 0.001); and significantly higher homeostasis model assessment of insulin resistance (HOMA-IR) (3.8 ± 1.5 vs. 2.9 ± 1.3, p = 0.001). Multivariate logistic regression analysis indicated that CC (OR = 0.73, 95% CI 0.58–0.91, p = 0.012), MM (OR = 0.68, 95% CI 0.56–0.83, p = 0.002), and hip BMD (OR = 0.30, 95% CI 0.17–0.55, p = 0.001) were protective factors against T2DM combined with SAR, while HOMA-IR (OR = 1.44, 95% CI 1.10–1.89, p = 0.013) was a risk factor.

The occurrence of SAR in T2DM patients is closely associated with reduced CC, MM, hip BMD, and increased IR. These indicators can serve as key targets for clinical risk assessment and intervention.