SAPS 3 admission score: an external validation in a general intensive care population

Abstract

Objectives: To validate the SAPS 3 admission score in an independent general intensive care case mix and to compare its performances with the APACHE II and the SAPS II scores.

Design: Cohort observational study.

Setting: A 26-bed general ICU from a Tertiary University Hospital.

Patients and participants: Eight hundred and fifty-one consecutive patients admitted to the ICU over an 8-month period. Of these patients, 49 were readmissions, leaving 802 patients for further analysis.

Intervention: None.

Measurements and results: APACHE II, SAPS II and SAPS 3 variables were prospectively collected; scores and their derived probability of death were calculated according to their original manuscript description. The discriminative power was assessed using the area under the ROC curve (AUROC) and calibration was verified with the Hosmer-Lemeshow goodness-of-fit test. The AUROC of the APACHE II model (AUROC = 0.823) was significantly lower than those of the SAPS II (AUROC = 0.850) and SAPS 3 models (AUROC = 0.854) (P = 0.038). The calibration of the APACHE II model (P = 0.037) and of the SAPS 3 global model (P = 0.035) appeared unsatisfactory. On the contrary, both SAPS II model and SAPS 3 model customised for Central and Western Europe had a good calibration. However, in our study case mix, SAPS II model tended to overestimate the probability of death.

Conclusion: In this study, the SAPS 3 admission score and its prediction model customised for Central and Western Europe was more discriminative and better calibrated than APACHE II, but it was not significantly better than the SAPS II.