Abstract
BACKGROUND: Obstructive sleep apnea (OSA) affects nearly one billion adults globally and significantly increases cardiovascular and metabolic risks, largely due to insulin resistance (IR). The triglyceride-glucose (TyG) index is a validated, cost-effective surrogate for IR. However, studies report conflicting associations between the TyG index and the presence or severity of OSA, possibly due to confounding factors such as age, gender, and obesity (BMI). This study aimed to clarify the independent TyG-OSA relationship by adjusting for confounders using propensity score matching (PSM). METHODS: This cross-sectional study included 394 patients with OSA (apnea-hypopnea index [AHI] ≥5 events/hour) and 285 controls (AHI <5 events/hour). PSM (1:1) balanced groups for age, gender, height, weight, and BMI. Differences in the TyG index between groups and across OSA severity (mild, moderate, severe) were analyzed pre- and post-PSM. Predictive performance was assessed using receiver operating characteristic (ROC) curves. RESULTS: Pre-PSM, the TyG index was significantly higher in patients with OSA than in controls (p < 0.001) and increased with severity (p < 0.001). Post-PSM (185 matched pairs), the TyG index remained significantly higher in moderate or severe OSA versus matched controls (p < 0.05) but not in mild OSA. ROC analysis demonstrated that PSM reduced the area under the curve (AUC) for predicting any OSA (from 0.709 to 0.628; p < 0.001) but substantially increased the AUC for predicting severe OSA (from 0.752 to 0.843; p < 0.001), improving sensitivity (0.754 to 0.796) and specificity (0.796 to 0.843). CONCLUSION: This PSM analysis provides robust evidence of an independent association between the TyG index and OSA, particularly in moderate-to-severe cases. The TyG index demonstrates strong predictive value for severe OSA, supporting its utility for risk stratification and monitoring in clinical practice.