Agreement between different eGFR equations in diagnosing contrast-induced acute kidney injury in patients undergoing elective coronary or peripheral angiography

Abstract Background In the present study, we aimed to compare CKD-EPI, MDRD, CKD-EPI creatinine-cystatin C equations and serum cystatin C and NGAL levels changes in assessing the occurrence of contrast-induced acute kidney injury (CI-AKI) in patients undergoing coronary and peripheral angiography and to evaluate the agreement between the CKD-EPI formula and the other parameters. Methods A cross-sectional study was performed in patients hospitalized with stable coronary artery disease and/or peripheral vascular disease, who underwent diagnostic and/or therapeutic invasive angiography using iodinated contrast agents. Standard laboratory parameters, NGAL, cystatin C levels, and eGFR were evaluated at admission and 48 hours after contrast substances exposure. Results Per different proposed definitions for CI-AKI, 7 patients (17.5 %) had a more than > 0.3 mg/dl increase in serum creati-nine, 1 (2.5 %) had a > 25 % increase in serum cystatin C and 9 (22.5 %) had a > 25% increase in serum NGAL. The agreement between attributions based on CKD-EPI was excellent with MDRD (K coefficient 0.875), and modest with CKD-EPI creatinine-cystatin, which had also a modest agreement with MDRD (K coefficient 0.285). An increase in cystatinc C of more than 25% from baseline was not in concordance with a significant decrease in eGFR calculated with any equation, and the same was observed for NGAL. Conclusions In the present study, the performance of the CKD-EPI equation in diagnosing CI-AKI was not significantly better or worse than MDRD, CKD-EPI creatinine-cystatin, serum creatinine, NGAL or cystatin C increase.