A comparison of predictive outcomes of APACHE II and SAPS II in a surgicalintensive care unit

The Acute Physiologic Score and Chronic Health Evaluation (APACHE) II and t he Simplified Acute Physiologic Scale (SAPS) II are two of the more commonl y employed predictors of outcome and performance in the intensive care unit setting. However, controversy persists about whether the scores generated by these systems have similar predictive value. This study compared the pre dicted mortalities derived from APACHE II and SAPS II and contrasted them t o the actual mortality in a surgical intensive care unit (SICU). Data for 1 665 patients admitted to the SICU between July 1994 and August 1997 were en tered into an SICU computerized database. From recorded demographic, hemody namic, and laboratory data, APACHE II and SAPS II scores were obtained with corresponding predicted mortalities. Patients were stratified by age into categories of less than and greater than 65 years old. Predicted mortalitie s by APACHE II and SAPS II were compared for each group. An additional anal ysis included a comparison of survivors and nonsurvivors. There was no sign ificant difference in predicted mortality between APACHE II and SAPS II in any of the groups. Actual mortality was 30 of 486 (6.2%) in patients less t han 65 years of age and 73 of II79 (6.2%) in patients 65 years of age or gr eater. The APACHE II and SAPS II predicted mortalities (mean SD) for patien ts less than 65 years of age were 10.5% +/- 10.6% and 10.9% +/- 13.3%, resp ectively (P > .05). The APACHE II and SAPS II predicted mortalities in pati ents 65 years of age or greater were 19.1% +/- 17.8% and 18.7% +/- 21.0%, r espectively (P > .05). Similarly, when patients were stratified by survival status, no significant difference was present between groups. However, in individual patients, a difference between APACHE II and SAPS II scores was often present. We conclude that although disparities between APACHE II and SAPS II predicted mortalities in individual patients may be significant, AP ACHE II and SAPS II have similar predictive value in a large SICU patient p opulation. However, both APACHE II and SAPS II systems overestimate mortali ty in SICU patients. Based on our results, we conclude that either system c an be used to measure quality of care in the SICU; however, neither system can be reliably applied to a single patient.