Association of insulin resistance indices with major adverse cardiovascular events in patients with acute myocardial infarction and chronic Kidney disease: a retrospective cohort study.

BACKGROUND: Patients with both acute myocardial infarction (AMI) and chronic kidney disease (CKD) face a markedly poor prognosis, a key driver of which is insulin resistance (IR). This study aims to systematically evaluate and compare the predictive performance of four commonly used IR indices for major adverse cardiovascular events (MACE), and to assess their incremental value over the GRACE score in this patient group. METHODS: This retrospective cohort study analyzed 1,803 patients with AMI and CKD. Multivariable Cox regression determined associations between IR indices and MACE. Predictive performance was evaluated using C-statistics, continuous net reclassification improvement (cNRI), and integrated discrimination improvement (IDI). RESULTS: During a median follow-up of 28.2 months, 462 MACE occurred. Patients with MACE were older, had higher female proportion, elevated GRACE score, and increased diabetes prevalence (all p < 0.05). the triglyceride-glucose (TyG) index and the atherogenic index of plasma (AIP) demonstrated linear associations with MACE risk, whereas TyG-body mass index (TyG-BMI) and metabolic score for insulin resistance (METS-IR) exhibited U-shaped nonlinear relationships (p < 0.001). The Area Under the Curve (AUCs) for MACE prediction were: TyG index 0.62, AIP 0.57, TyG-BMI 0.58, and METS-IR 0.56. Incorporating IR indices significantly enhanced the GRACE score's predictive capacity, with TyG index providing the greatest incremental improvement (cNRI = 0.137, IDI = 0.03). CONCLUSION: IR indices predict outcomes in patients with AMI and CKD and enhance GRACE score prediction, with TyG index demonstrating superior performance.