High-sensitivity C-reactive protein-triglyceride glucose index (CTI) has demonstrated superior clinical utility as a dual-parameter indicator integrating both insulin resistance (IR) and systemic inflammatory status. However, the association between CTI and the risk of obstructive sleep apnea (OSA) remains unclear. Therefore, this study aimed to investigate this association utilizing data from the National Health and Nutrition Examination Survey (NHANES) database.

The analysis was based on data from the 2015–2018 NHANES. Multivariate logistic regression analyses were used to investigate the association between CTI and OSA, with additional exploration of the consistency of the results through restricted cubic spline (RCS) regression, receiver operating characteristic (ROC), and subgroup analyses.

This cross-sectional study (n = 3512) identified a robust positive association between CTI and the risk of OSA. Full adjustment revealed 14 % increased OSA odds per CTI unit (OR = 1.14, 95 %CI 1.05–1.24), with the highest quartile demonstrating 1.35–fold elevated risk versus the lowest (95 %CI 1.08–2.70). Threshold analysis revealed nonlinear dynamics: CTI <8.755 showed 78 % OSA risk increase per unit (p < 0.001), versus 19 % increase above this threshold (p = 0.024). Subgroup analyses confirmed consistent associations across demographics. CTI outperformed hs-CRP and TyG in OSA discrimination (AUC = 0.597, 95 %CI 0.578–0.615).

This study demonstrates that elevated levels of the CTI are correlated with risk for OSA, indicating its potential utility as a biomarker for OSA.