Contrast-Induced Nephropathy: Evaluation of Preventive Strategies Based on Serum Creatinine and Cystatin C in Patients with Moderate to Severe Chronic Kidney Disease – A Randomized Clinical Trial

Background Contrast-induced acute kidney injury (CI-AKI) remains a clinically relevant complication, with uncertainties regarding its true epidemiology, pathophysiology, optimal diagnostic methods, and preventive strategies. As the global volume of contrast-enhanced imaging procedures continues to rise, there is a critical need to refine early detection and prevention approaches. Methods This prospective, randomized clinical trial included patients with peripheral artery disease requiring contrast-enhanced diagnostic and/or therapeutic procedures at a public hospital from February 2022 to March 2024. Patients were stratified into three groups based on their estimated glomerular filtration rate (eGFR): control group (eGFR > 60 mL/min/1.73m²), Group 1 (eGFR < 30 mL/min/1.73m²), and Group 2 (eGFR 30–59 mL/min/1.73m²). Within each group, patients were randomized into either a standard hydration protocol ( 1 mL/kg/h for 12 hours before and 12 hours after the procedure ) or an intervention protocol , which included atorvastatin (80 mg 12 hours before and 40 mg after the procedure) and oral N-acetylcysteine (600 mg every 12 hours, starting 24 hours before and continuing for 24 hours after the procedure), in addition to intravenous isotonic saline hydration. Serum creatinine (sCr) and cystatin C (sCys C) levels were measured at baseline, 24h, and 72h post-procedure. Results A total of 76 patients were included: 45 in the control group, 23 in Group 2, and 8 in Group 3 . There were no significant differences in baseline clinical or demographic characteristics between groups. Although numerically more CI-AKI cases were identified using sCys C, it did not demonstrate statistically significant superiority over sCr as a diagnostic biomarker (Kappa = 0.07, p = 0.554). In the control group , logistic regression analysis showed that the intervention was associated with a lower incidence of CI-AKI when sCys C was used as the diagnostic criterion (OR 0.81; 95% CI, 0.65–0.98; p = 0.025). However, this effect was not statistically significant in patients with impaired renal function. Factorial ANOVA and dispersion analysis did not confirm a significant effect of the intervention across groups or its interaction with renal function status when evaluating variations in both sCys C and sCr (p > 0.05). Conclusions When using sCys C as a diagnostic criterion, the combination of high-dose atorvastatin and N-acetylcysteine demonstrated a protective effect against CI-AKI in patients with normal renal function . However, this benefit was not observed in patients with moderate or severe chronic kidney disease, regardless of the biomarker used (sCr or sCys C). Furthermore, despite identifying more CI-AKI cases, sCys C did not exhibit statistically significant superiority over sCr for early CI-AKI diagnosis.