Advanced age and preinjury warfarin anticoagulation increase the risk of mortality after head trauma

BACKGROUND: A large population of patients on oral anticoagulants is exposed to the risk of traumatic brain injury (TBI). Effects of age and anticoagulation on TBI outcomes need to be assessed separately. METHODS: Retrospective analysis of consecutive series of TBI patients (age 18 years and older) in a suburban teaching hospital. RESULTS: A total of 1,493 adult blunt head trauma patients between January 2001 and May 2005 were analyzed. Of these, 159 patients were warfarin-anticoagulated at the time of trauma. The mortality in anticoagulated patients was statistically significantly higher than in the control group (38/159, 23.9% vs. 66/1,334, 4.9%; p < 0.001; odds ratio 6.0). Mortality of patients over 70 years of age was significantly higher than in the younger population (p < 0.001). Both mortality and the occurrence of intracranial hemorrhage (ICH) after head trauma were significantly increased with higher INR (Cochran's linear trend p < 0.001), especially with INR over 4.0 (mortality 50%, risk of ICH 75%). Preinjury warfarin anticoagulation and age were found to be predictive of survival in a binary logistic regression model (92.5% correct prediction, p = 0.027). Addition of Injury Severity Score and initial Glasgow Coma Score to this model only modestly improved its predictive performance (95.4% correct prediction, p < 0.001). CONCLUSIONS: Both age and warfarin anticoagulation are independent predictors of mortality after blunt TBI. Warfarin anticoagulation carries a six-fold increase in TBI mortality. Age over 70 years and excessive anticoagulation are associated with higher mortality, as well.