Abstract: Background Myocardial injury after noncardiac surgery (MINS) is a common cardiovascular complication following noncardiac surgery. The metabolic score for insulin resistance (METS-IR), as a novel surrogate marker of insulin resistance, its association with perioperative myocardial injury and the relationship with cardiovascular-kidney-metabolic (CKM) syndrome staging remain unclear. Objective To investigate the association between METS-IR index and MINS in patients undergoing noncardiac surgery, and to analyze its relationship with CKM syndrome staging. Methods We retrospectively analyzed 12, 086 patients who underwent noncardiac surgery at the First Medical Center of Chinese PLA General Hospital from January 2020 to December 2022. Patients were categorized into tertiles (T1-T3) based on METS-IR index. Multivariable logistic regression was used to assess the association between METS-IR and MINS. Subgroup analyses were performed by age, sex, diabetes, hypertension, BMI, and CKM syndrome stage, with interaction tests to evaluate consistency of associations across subgroups.Results The incidence of MINS was 7.1% (853/12, 086). In the fully adjusted model, compared with T1, T3 showed significantly elevated MINS risk (OR=1.45, 95%CI 1.14-1.85, P=0.002), while T2 showed no significant difference (OR=1.09, 95%CI 0.86-1.39, P=0.463). A positive dose-response relationship was observed between METS-IR and MINS (P for trend <0.001). Subgroup analyses demonstrated that the association between METS-IR and MINS remained consistent across different age groups (<65 vs ≥65 years), sex, diabetes, hypertension, BMI, and CKM stages (all P for interaction >0.05). For secondary outcomes, T3 group also showed increased acute kidney injury risk (OR=1.28, 95%CI 1.00-1.63, P=0.048). Conclusion METS-IR index demonstrates a positive association with MINS risk in patients undergoing noncardiac surgery. Patients with high METS-IR (T3 group) had 45% increased MINS risk. METS-IR may serve as a convenient tool for perioperative cardiovascular risk assessment.