Association of the TyG index and its body fat distribution composites with CHD and MACE risk in adults with OSAHS: incremental discrimination and exploratory mediation analysis.

INTRODUCTION

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is closely associated with coronary heart disease (CHD) and adverse cardiovascular outcomes, but the comparative value of the triglyceride-glucose (TyG) index and its body fat distribution composites for cardiovascular risk stratification in OSAHS remains unclear.

METHODS

We assessed the associations of TyG, TyG-weight-adjusted waist index (TyG-WWI), TyG-Chinese visceral adiposity index (TyG-CVAI), and TyG-body roundness index (TyG-BRI) with prevalent CHD and incident major adverse cardiovascular events (MACE) in adults with OSAHS. This single-center retrospective observational study included 1,122 adults with OSAHS who underwent both polysomnography and coronary angiography, including 533 patients with CHD and 589 without CHD. TyG-related indices were standardized and analyzed per 1-standard deviation increase. Multivariable logistic regression, restricted cubic spline analysis, Cox proportional hazards models, time-dependent receiver operating characteristic analysis, and exploratory statistical decomposition were performed.

RESULTS

All TyG-related indices were independently associated with prevalent CHD after full adjustment. TyG-WWI showed the strongest association (odds ratio 3.21, 95% confidence interval 2.68-3.89 per 1-standard deviation increase). Adding TyG-WWI to conventional risk factors plus apnea-hypopnea index provided the greatest improvement in CHD discrimination (area under the curve 0.802; integrated discrimination improvement 0.150; continuous net reclassification improvement 0.706; all P<0.001). During a median follow-up of 17 months, 80 MACE occurred, and TyG-WWI showed the strongest association with incident MACE among the evaluated indices(hazard ratio 1.545, 95% confidence interval 1.217-1.961). Exploratory statistical decomposition suggested potential indirect pathway signals involving TyG-WWI and TyG-CVAI.

DISCUSSION: In this selected high-risk cohort of adults with OSAHS undergoing coronary evaluation, TyG and its adiposity-based composites were associated with prevalent CHD and showed supportive associations with follow-up MACE. TyG-WWI showed the most consistent cross-sectional, supportive longitudinal, and incremental discriminative value, suggesting its potential as a candidate marker for cardiovascular risk stratification. Given the limited MACE events and the exploratory nature of the statistical decomposition, these findings should be interpreted cautiously and validated prospectively.