An Inflammation–Renal Composite Approach to Predict Contrast-Induced Nephropathy in Acute Myocardial Infarction

Background Contrast-induced nephropathy (CIN) remains an important complication in patients with acute myocardial infarction (MI) undergoing percutaneous coronary intervention (PCI) and is associated with adverse clinical outcomes. Both systemic inflammation and baseline renal dysfunction may contribute to susceptibility to contrast-related renal injury. We aimed to develop and internally validate an inflammation–renal composite score for predicting CIN and to examine the association between CIN and in-hospital mortality. Methods In this retrospective cohort study, 1,286 consecutive patients with STEMI or NSTEMI undergoing PCI were included. CIN was defined as an increase in serum creatinine ≥0.5 mg/dL or ≥25% within 48–72 hours after contrast exposure. An inflammation–renal composite (IRIS) score integrating inflammatory and renal parameters was derived using penalized regression. Model discrimination and calibration were evaluated, and the incremental predictive value beyond a clinical model was assessed. Results CIN occurred in 427 patients (33.2%). In multivariable analysis, age (OR 1.03 per year, 95% CI 1.02–1.04), chronic kidney disease (OR 5.05, 95% CI 2.64–9.63), and the IRIS score (OR 2.72 per standard deviation increase, 95% CI 2.16–3.42) were independently associated with CIN. Incorporation of the IRIS score resulted in a modest improvement in model discrimination (AUC 0.686 vs. 0.698). CIN was independently associated with increased in-hospital mortality (OR 3.35, 95% CI 1.58–7.11). Conclusion In patients with acute MI undergoing PCI, CIN was common and independently associated with in-hospital mortality. The IRIS score, derived from routinely available inflammatory and renal parameters, was independently associated with CIN and may represent a practical bedside tool for risk stratification before PCI. Prospective multicenter studies are warranted to externally validate its clinical utility.