External validation of the CA-AKI score in patients with acute coronary syndrome: A real-world cohort analysis from Asia

Abstract Background Contrast-associated acute kidney injury (CA-AKI) is associated with long-term impairment of kidney function, the need for renal replacement therapy, and subsequent all-cause deaths. A practical risk score, the CA-AKI risk score is derived for the prediction of contrast-associated acute kidney injury. However, this novel score has not received sufficient evidence of external validation in real-world studies, especially in Asian individuals. Methods Short-term endpoints and long-term endpoints were assessed in 8,816 patients with acute coronary syndrome enrolled in a large Asia registry. Discrimination was assessed by Harrell’s C statistic, and calibration was assessed by calibration plots. The ability of the CA-AKI score to predict short-term and long-term prognosis was assessed. Results CA-AKI occurred in 5.3% of the patients, with a stepwise increase of CA-AKI rates from the lowest to the highest of the 4 risk categories. When predicting the risk of CA-AKI, both discrimination and calibration were helpful in model 2 (C-index: 0.72; slope: 0.97) and in model 1(C-index: 0.69; slope: 1.02). The risks of 1-year all-cause mortality and 1-year bleeding were higher in CA-AKI patients (HR: 2.70 [95% CI: 2.22-3.30] and HR: 1.76 [95% CI: 1.41-2.46]; respectively). Conclusion The updated CA-AKI risk score could accurately identify patients with contrast-associated acute kidney injury, the occurrence of which is strongly associated with long-term mortality and bleeding.