Associations of QCT-derived body composition parameters with HOMA-IR-defined metabolic burden in patients with type 2 diabetes mellitus: a retrospective cross-sectional study

Insulin resistance is central to type 2 diabetes mellitus (T2DM) and is linked to abdominal adiposity, ectopic fat deposition, and skeletal muscle metabolism. However, HOMA-IR is a fasting surrogate measure that may be influenced by endogenous insulin secretion and treatment status in established T2DM. This study investigated associations between quantitative computed tomography (QCT)-derived body composition parameters and HOMA-IR-defined metabolic burden. This retrospective cross-sectional study included 245 patients with T2DM who underwent abdominal QCT. Patients were categorized into low, middle, and high HOMA-IR groups by cohort-specific tertiles; high HOMA-IR was defined as the highest tertile (> 3.95). QCT parameters included visceral fat area (VFA), subcutaneous fat area (SFA), VFA/SFA ratio, intermuscular adipose tissue, skeletal muscle area and skeletal muscle index at L3 (SMI-L3), liver fat content, mean pancreatic fat content, and L1–L2 volumetric bone mineral density. Group comparisons, correlation analyses, and multivariable logistic regression were performed. Sensitivity analyses excluded basal insulin users and analyzed log-transformed HOMA-IR as a continuous outcome. Of the 245 patients, 82, 81, and 82 were assigned to the low, middle, and high HOMA-IR groups, respectively. VFA, SFA, VFA/SFA ratio, SMI-L3, and liver fat content differed significantly across tertiles. HOMA-IR was positively correlated with VFA, SFA, skeletal muscle area at L3, SMI-L3, and liver fat content. In the fully adjusted logistic regression model, VFA showed the largest point estimate for high HOMA-IR (odds ratio [OR] 2.450, 95% confidence interval [CI] 1.665–3.604, P < 0.001). Liver fat content (OR 1.618, 95% CI 1.180–2.217, P = 0.003), SMI-L3 (OR 1.659, 95% CI 1.054–2.611, P = 0.029), and VFA/SFA ratio (OR 1.501, 95% CI 1.065–2.115, P = 0.020) were also associated with high HOMA-IR. In sensitivity analyses, only VFA and liver fat content remained consistently significant. VFA and liver fat content were the most consistent QCT-derived correlates of HOMA-IR-defined metabolic burden in patients with T2DM. Findings for VFA/SFA ratio and SMI-L3 were not reproduced in sensitivity analyses and should therefore be considered exploratory.