Abstract
BACKGROUND: Insulin resistance contributes to cognitive dysfunction in patients with coronary heart disease (CHD). We examined the dose-response relationship between the triglyceride-glucose (TyG) index and cognitive status in this population. METHODS: We analyzed data from 839 CHD patients, classifying cognitive function as Normal Cognition, Mild Cognitive Impairment, Severe Cognitive Impairment. Logistic regression and restricted cubic splines modeled the associations. We calculated net reclassification improvement (NRI) and integrated discrimination improvement (IDI) to test the predictive value of TyG beyond standard risk factors. RESULTS: The severity of cognitive impairment increased with increasing TyG levels. In fully adjusted models, compared to the lowest tertile, the highest TyG tertile was associated with mild cognitive impairment (OR: 1.866, 95% CI: 1.268-2.748) and severe cognitive impairment (OR: 3.255, 95% CI: 1.870-5.668). Spline analysis showed a J-shaped curve for severe cognitive impairment (P for non-linearity = 0.029) and a linear trend for mild cognitive impairment (P for non-linearity = 0.619). Adding TyG to baseline models improved risk reclassification for severe cognitive impairment (NRI: 0.405, P < 0.001; IDI: 0.031, P = 0.023) and mild cognitive impairment (NRI: 0.185, P = 0.024). CONCLUSION: In patients with CHD, the TyG index identifies a specific metabolic threshold associated with severe cognitive impairment. The distinct non-linear trajectory and significant reclassification improvement suggest that the TyG index captures residual metabolic-inflammatory risk not addressed by traditional factors, highlighting its utility as a target for neuroprotective strategies.