Validation study of EuroSCORE II for dialysis patients: A single-center study in Japan

The European System for Cardiac Operative Risk Evaluation (EuroSCORE) II is a predictive model for in-hospital mortality after cardiac surgery. Although it has good performance among the general population undergoing cardiac surgery, it has not been validated among dialysis patients, who have a higher rate of mortality after cardiac surgery. This study aimed to evaluate the performance of the model in predicting in-hospital mortality in maintenance dialysis patients undergoing cardiac surgery.

This retrospective, single-center study included adult patients on maintenance dialysis who underwent open cardiac surgery at our institution. Calibration performance of EuroSCORE II for in-hospital death was determined based on the comparison between expected and observed mortalities for low- (EuroSCORE II <4 %), intermediate- (4-8 %), and high-risk (>8 %) groups. The area under receiver operating characteristic curve (AUROC) was investigated to determine the model's discrimination performance.

A total of 163 patients (male, 73.6 %; median age, 70 years; median dialysis vintage, 9 years; median EuroSCORE II, 3.3 %) were included. The mortality rate was 9.2 %. The observed mortality rates (vs. mean expected mortality) rates were 2.1 % (vs. 2.4 %), 7.5 % (vs. 5.5 %), and 34.5 % (vs. 21.1 %) in the low-, intermediate-, and high-risk groups, respectively. Its AUROC was 0.825 (95 % confidence interval, 0.711-0.940).

Although EuroSCORE II model adequately estimated in-hospital mortality in the low-and intermediate-risk groups (EuroSCORE II <8 %), it underestimated in-hospital mortality in the high-risk group (EuroSCORE II >8 %) among maintenance dialysis patients. The discrimination performance of the model for in-hospital death was good among maintenance dialysis patients.