Association of glycemic variability and ultrasound muscle assessment with pre-sarcopenia in older adults with type 2 diabetes: A cross-sectional study.

Glycemic variability (GV) contributes to metabolic complications in type 2 diabetes mellitus (T2DM). Pre-sarcopenia is common in older adults with T2DM, but its link with GV remains unclear. Muscle ultrasound provides a noninvasive means to assess muscle status. This study aimed to investigate the association between GV and pre-sarcopenia in older adults with T2DM, evaluating key GV parameters as potential predictors of muscle health deterioration. This cross-sectional study was conducted in the Department of Endocrinology, Nanjing Central Hospital, from January 2023 to March 2024. A total of 292 hospitalized adults aged ≥65 years with T2DM were screened, and 260 eligible participants were included after applying predefined inclusion and exclusion criteria. Each participant underwent continuous glucose monitoring, handgrip strength testing, short physical performance battery assessment, and high-resolution muscle ultrasound evaluation. Pre-sarcopenia was defined according to the Asian Working Group for Sarcopenia 2019 criteria. GV metrics, including mean amplitude of glycemic excursions, coefficient of variation (CV), and standard deviation of blood glucose (SDBG), were analyzed. Correlation and multiple logistic regression analyses were performed to evaluate the associations between GV, ultrasound parameters, and pre-sarcopenia after adjustment for potential confounders. The pre-sarcopenia group was older, had higher systolic blood pressure and creatinine, and lower prealbumin and free triiodothyronine levels. GV was significantly worse in the pre-sarcopenia group. Postprandial glucose levels peaked earlier and reached higher levels in pre-sarcopenic individuals. After adjustment, higher SDBG (odds ratio [OR]: 12.16, 95% confidence interval [CI]: 2.12-69.74, P = .005) and CV (OR: 1.44, 95% CI: 1.10-1.88, P = .008) independently predicted pre-sarcopenia. Ultrasound showed reduced biceps brachii thickness (OR: 0.81, 95% CI: 0.67-0.98, P = .026), increased gastrocnemius thickness (OR: 1.21, 95% CI: 1.03-1.42, P = .018), and higher echogenicity (OR: 0.86, 95% CI: 0.76-0.97, P = .015) were significantly associated with risk. Pre-sarcopenic older adults with T2DM exhibited greater GV instability, lower muscle thickness, and higher echogenicity. GV parameters, particularly SDBG and CV, were strong predictors of pre-sarcopenia risk.