Is the EuroSCORE II reliable to estimate operative mortality among octogenarians?

OBJECTIVES: Concerns have been raised about the predictive performance (PP) of the EuroSCORE I (ES I) to estimate operative mortality (OM) of patients aged ≥80. The EuroSCORE II (ES II) has been described to have better PP of OM but external validations are scarce. Furthermore, the PP of ES II has not been investigated among the octogenarians. The goal of the study was to compare the PP of ES II and ES I among the overall population and patients ≥ 80.

METHODS: The ES I and ES II were computed for 7161 consecutive patients who underwent major cardiac surgery in a 7-year period. Discrimination was assessed by using the c- index and calibration with the Hosmer-Lemeshow (HL) and calibration plot by comparing predicted and observed mortality.

RESULTS: From the global cohort of 7161 patients, 832 (12%) were ≥80. The mean values of ES I and ES II were 7.4±9.4 and 5.2±9.1 respectively for the whole cohort, 6.3±8.6 and 4.7±8.5 for the patients <80, 15.1±11.8 and 8.5±11.0 for the patients ≥80. The mortality was 9.38% (≥80) versus 5.18% (<80). The discriminatory power was good for the two algorithms among the whole population and the <80 but less satisfying among the ≥80 (AUC 0.64 [0.58-0.71] for ES I and 0.67 [0.60-0.73] for the ES II without significant differences (p = 0.35) between the two scores. For the octogenarians, the ES II had a fair calibration until 10%-predicted values and over-predicted beyond.

CONCLUSIONS: The ES II has a better PP than the ES I among patients <80. Its discrimination and calibration are less satisfying in patients ≥80, showing an overestimation in the elderly at very high-surgical risk. Nevertheless, it shows an acceptable calibration until 10%- predicted mortality.