Abstract
<title>Abstract</title> <p>Background Contrast-Induced Nephropathy (CIN) is a serious complication of primary percutaneous coronary intervention (PPCI) for ST-segment elevation myocardial infarction (STEMI), increasing morbidity and mortality. This study aimed to determine CIN prevalence, identify independent risk factors, and develop a predictive model. Methods This retrospective cohort substudy of the Mashhad STEMI Registry analyzed 916 consecutive STEMI patients undergoing PPCI. CIN was defined as post-procedural creatinine increase ≥ 0.5 mg/dL or ≥ 25% from baseline. Univariable and multivariable logistic regression identified predictors. Model performance was evaluated using ROC curve analysis. Results CIN prevalence was 16.6% (152/916). Univariable analysis identified significant predictors: higher systolic BP (OR 1.013), diastolic BP (OR 1.019), heart rate (OR 1.019), neutrophil percentage (OR 1.037), NLR (OR 1.126), urea (OR 1.019), CK-MB (OR 1.004), sodium (OR 1.081), and calcium (OR 2.397). Higher baseline creatinine (OR 0.320) and lymphocyte percentage (OR 0.957) were inversely associated. Multivariable analysis revealed independent predictors: lower baseline creatinine (aOR 0.206, p = 0.002), higher systolic BP (aOR 1.016, p = 0.004), and higher peak CK-MB (aOR 1.002, p = 0.004). The risk score showed good discriminatory power (AUC 0.718, 95% CI 0.644–0.792, p < 0.001). Risk stratification identified five groups with CIN rates from 7.3% to 39.4%. Conclusions CIN affects one in six STEMI patients post-PPCI. A simple model using lower baseline creatinine, higher systolic BP, and higher peak CK-MB effectively stratified risk. This tool may aid in identifying high-risk patients for targeted prevention.</p>