EFFECT OF PREINJURY ILLNESS ON TRAUMA PATIENT SURVIVAL OUTCOME

Data from 11,156 patients treated at the four Major Trauma Outcome Stu dy controlled sites were used to estimate the effect on survival of ea ch APACHE II preinjury illness condition (PIC). A case-control methodo logy was applied; 544 patients (4.8%) had one or more PICs. For each p atient with a specific PIC we identified a set of matching patients wi th no PICs. A patient matches a PIC patient if both have the same mech anism of injury, the same coding of Revised Trauma Score variables (Gl ascow Coma Scale score, systolic blood pressure, respiratory rate), th e same coded age per A Severity Characterization of Trauma) (ASCOT), a nd if they differ by no more than 0.5 for A, B, and C (the ASCOT compo nents for serious injuries). The estimated survival probability for a PIC patient is either the survival rate for the patient's matched set or, if there are no matches, the patient's ASCOT survival probability. The survival probabilities were used to compare the actual and predic ted numbers of survivors for each PIC, using z and W statistics. Compu tations of z and W were also made using ASCOT survival probabilities f or each PIC patient. The results indicate profound effects of five PIC s (hepatic, cardiovascular, respiratory, renal, diabetes) on trauma pa tient outcomes. Conclusion: Pre-existing organ dysfunction has a profo und effect on patient outcome even after controlling for age, anatomic and physiologic severity, and mechanism of injury. But, because of th eir relatively low incidence in this sample, PICs did not strongly inf luence institutional outcome performance as measured by z and W values .