The Relationship Between Poor Glycemic Control and Diaphragmatic Thickness in Adults with Type 2 Diabetes Mellitus: A...

Diabetes mellitus (DM) is associated with multiple systemic complications, yet its effects on respiratory muscle structure remain insufficiently characterized. This study aimed to evaluate diaphragmatic morphology in patients with type 2 DM and to determine whether glycemic control is associated with diaphragmatic thickness.

A total of 120 participants were enrolled, including 60 patients with type 2 DM and 60 healthy controls. Demographic, biochemical, and diaphragmatic ultrasound parameters were assessed, including right and left diaphragm thickness (DT) during inspiration and expiration, diaphragmatic excursion (DE), and costophrenic angle (CPA). All patients with DM underwent electromyography for evaluation of peripheral neuropathy. Diabetic participants were further stratified according to glycemic control using an HbA1c threshold of 7%. Correlation analyses and multivariable linear regression models adjusted for age and body mass index (BMI) were performed to examine the association between HbA1c and diaphragmatic parameters.

Compared with controls, patients with DM were older and had higher fasting glucose levels but lower total cholesterol, whereas BMI and other biochemical parameters were comparable. Peripheral neuropathy was identified in 28.3% of patients with DM, but was not associated with significant differences in DT, DE, or CPA. In the three-group analysis, right and left DT measured during both inspiration and expiration differed significantly among well-controlled DM, poorly controlled DM, and control groups, whereas DE and CPA remained similar. Within the DM cohort, higher HbA1c levels were significantly associated with lower right and left DT values. These inverse associations remained independent after adjustment for age and BMI, while no independent associations were observed between HbA1c and either DE or CPA.

Poorer glycemic control was associated with reduced diaphragmatic thickness in patients with T2DM. Ultrasonographic assessment may offer a non-invasive approach for detecting early respiratory muscle involvement, although its clinical and functional relevance should be validated in future prospective studies.