A Prospective Comparison of Serum Cystatin C and Creatinine in the Early Diagnosis of Contrast-Induced Nephropathy in North-Eastern Nigeria

Aims: We aimed to compare the diagnostic efficacy of serum cystatin C (sCyC) for contrast induced nephropathy (CIN) in north-eastern Nigerians undergoing investigations requiring the administration of iodinated contrast media. Methods: In this prospective study of 150 patients undergoing investigations requiring the administration of iodinated contrast. The demographic, levels of sCr and cystatin c at baseline, 24, 48, 72hours and 3 months after the procedure were noted. Increase of 0.5 mg/dl or 25% from baseline sCr was used to define CIN and optimum cut off of sCyC for CIN diagnosis was obtained using Receiver Operating Characteristic (ROC) curve analysis. Sensitivity and specificity of sCyC for diagnosis of CIN was obtained using Receiver Operating Characteristic (ROC) curve analysis. Results: At 24 hours of contrast media (CM) exposure, Cystatin C at 24 hours had maximum sensitivity and specificity of 86.2% and 81.0% respectively indicating a good diagnostic efficacy for CIN, however, a rise in serum creatinine was not significant. The optimum cut off of sCyC for diagnosing CIN was found to be a rise of 10% from baseline (AUC – 0.867; sensitivity – 86.2%, specificity – 81.0%). Conclusion: We may conclude that a rise of 10% in sCyC at 24 h has a good sensitivity and specificity and is reliable in the early diagnosis of CIN.