Comparison of the Rapid Emergency Medicine Score and APACHE II in Nonsurgical Emergency Department Patients

OBJECTIVES: To improve the Rapid Acute Physiology Score (RAPS) as a predictor of in-hospital mortality in the nonsurgical emergency department (ED) by including age and oxygen saturation, and to compare this new system, Rapid Emergency Medicine Score (REMS), with the Acute Physiology and Chronic Health Examination (APACHE II) with reference to predictive accuracy. METHODS: This was a prospective cohort study. One hundred sixty-two critically ill patients consecutively admitted to the intensive care unit (ICU) during the period of one year, and 865 nonsurgical patients presenting to an adult emergency department (ED) and admitted to a medical department of a 1200-bed university hospital during two months, were enrolled. For all entries to the ED, RAPS was calculated and developed to include noninvasive peripheral oxygen saturation and patient age (REMS), as well as laboratory tests (APACHE II). These scores were calculated for each patient. RESULTS: REMS was found to be superior to RAPS in predicting in-hospital mortality both in the critically ill patients admitted to the ICU and in the total sample (area under receiver-operating characteristic curve [AUC] 0.910 +/- 0.015 for REMS compared with 0.872 +/- 0.022 for RAPS, p < 0.001). An increase of 1 point in the 26-point REMS scale was associated with an odds ratio of 1.40 for in-hospital death (95% confidence interval = 1.36 to 1.45, p < 0.0001). The more advanced APACHE II was not found to be superior to REMS (AUC: 0.901 +/- 0.015, p = 0.218). CONCLUSIONS: RAPS could be improved as a predictor of in-hospital mortality in the nonsurgical ED by including oxygen saturation and patient age to the system. This new scoring system, REMS, had the same predictive accuracy as the well-established, but more complicated, APACHE II.