Threshold effects of insulin resistance on cognitive function in coronary heart disease: the non-linear diagnostic value of the triglyceride-glucose index

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: = 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.