External validation and comparison of two risk scores for predicting post-contrast acute kidney injury in patients undergoing coronary intervention

Objective To screen out the more suitable risk score on the prediction of post-contrast acute kidney injury(PC-AKI)for Chinese people,by comparing the accuracy values of the Mehran risk score and the domestic risk score for prediction of PC-AKI through external verification.Methods We consecutively enrolled 594 patients who underwent coronary angiography(CAG)or percutaneous coronary intervention(PCI)in our hospital.The correction ability of the two risk scoring systems was assessed by the Hosmer-Lemeshow goodness-of-fit test.The discrimination for PC-AKI was measured for the two scoring systems by area under the receiver operating characteristic(ROC)curve.Furthermore,the incidence of PC-AKI and the correlation with hospital adverse events were statistically analyzed with the stratification scores of two risk scoring systems.Results The incidence of PC-AKI was 5.2%(31/594)in our hospital.Both the Mehran risk score and domestic risk score showed good correction ability(Hosmer-Lemeshow statistic test,Mehran risk score,χ²=2.42,P=0.88;and domestic risk score,χ²=5.98,P=0.43,respectively).However,the domestic risk score had a higher predictive accuracy for PC-AKI compared with the Mehran risk score.The area under the ROC curve for the Mehran risk score was 0.56(95%CI 0.48~0.63),while the area under the ROC curve for the domestic risk score was 0.71(95%CI 0.61~0.80).In addition,the rate of PC-AKI was 2.1%,6.2%,18.4%,and 33.3% with the risk categories of low-,moderate-,high-and very high-risk in the domestic risk scoring system,respectively(P<0.01).But the trend was not obviously found for the Mehran risk score,and the incidences of PC-AKI were 10.1%,13.2%,24.0% and 25.0%(P=0.125),respectively,with the risk categories of low-,moderate-,high-and very high-risk.Furthermore,the domestic risk score was highly positively correlated with the incidence of in-hospital adverse event(OR=1.20,95%CI 1.09~1.32,P<0.01).However,this relation did not hold true for the Mehran risk score(OR=1.06 95% CI 0.99~1.14,P=0.061).Conclusion Both the Mehran risk score and domestic risk score have a high goodness of fit.But the domestic risk score tends to be more accurate for prediction of PC-AKI.Therefore,the domestic risk score may be more suitable for the Chinese patients undergoing coronary intervention.