CUSTOMIZED PROBABILITY-MODELS FOR EARLY SEVERE SEPSIS IN ADULT INTENSIVE-CARE PATIENTS

Objective.-To develop customized versions of the Simplified Acute Phys iology Score II (SAPS II) and the 24-hour Mortality Probability Model II (MPM II24) to estimate the probability of mortality for intensive c are unit patients with early severe sepsis. Design and Setting.-Logist ic regression models developed for patients with severe sepsis in a da tabase of adult medical and surgical intensive care units in 12 countr ies. Patients.-Of 11 458 patients in the intensive care unit for at le ast 24 hours, 1130 had severe sepsis based on criteria of the American College of Chest Physicians and the Society of Critical Care Medicine (systemic inflammatory response syndrome in response to infection, pl us hypotension, hypoperfusion, or multiple organ dysfunction). Results .-In patients with severe sepsis, mortality was higher (48.0% vs 19.6% among other patients) and 28-day survival was lower. The customized S APS II was well calibrated (P=.92 for the goodness-of-fit test) and di scriminated well (area under the receiver operating characteristic [RO C] curve, 0.78). Performance in the validation sample was equally good (P=.85 for the goodness-of-fit test; area under the ROC curve, 0.79). The customized MPM II24 was well calibrated (P=.92 for the goodness-o f-fit test) and discriminated well (area under the ROC curve, 0.79). P erformance in the validation sample was equally good (P=.52 for the go odness-of-fit test; area under the ROC curve, 0.75). The models are in dependent of each other; either can be used alone to estimate the prob ability of mortality of patients with severe sepsis. Conclusions.-Cust omization provides a simple technique to apply existing models to a su bgroup of patients. Accurately assessing the probability of hospital m ortality is a useful adjunct for clinical trials.