PREDICTIVE VALUE OF SEVERITY SCORING SYSTEMS - COMPARISON OF 4 MODELSIN TUNISIAN ADULT INTENSIVE-CARE UNITS

Objectives: To compare the performance of four severity scoring system s: the Acute Physiology and Chronic Health Evaluation (APACHE) II, the new versions of the Mortality Prediction Model (MPM0 and MPM24), and the Simplified Acute Physiology Score (SAPS) II. Design: A prospective cohort study. Setting: Three Tunisian intensive care units (ICUs). Pa tients: Consecutive, unselected adult patients (n = 1325). Interventio ns: None. Measurements and Main Results: Overall, observed death rates were higher than predicted by all models except MPM0. All the evaluat ed scoring systems had good discrimination power as expressed by area under the receiver operating characteristics curve, but their calibrat ion was less perfect when compared with original validation reports. T here were no major differences between the models with regard either t o discrimination or calibration performance. Conclusion: Despite an ov erall good discrimination, APACHE II, MPM0, MPM24, and SAPS II showed a less satisfactory calibration in our Tunisian sample of ICU patients . Part of the models inaccuracy could be related to quality of care pr oblems in our ICUs, but this issue needs further analysis.