Prevalence and implications of preinjury warfarin use: an analysis of the National Trauma Databank.

OBJECTIVES To describe the prevalence of preinjury warfarin use in a large national sample of trauma patients and to define the relationship between preinjury warfarin use and mortality. DESIGN Retrospective cohort study. SETTING The National Trauma Databank (7.1). PATIENTS All patients admitted to eligible trauma centers during the study period; 1,230,422 patients (36,270 warfarin users) from 402 centers were eligible for analysis. MAIN OUTCOME MEASURES Prevalence of warfarin use and all-cause in-hospital mortality. Multivariate logistic regression was used to estimate the odds ratio (OR) for mortality associated with preinjury warfarin use. RESULTS Warfarin use increased among all patients from 2.3% in 2002 to 4.0% in 2006 (P < .001), and in patients older than 65 years, use increased from 7.3% in 2002 to 12.8% in 2006 (P < .001). Among all patients, 9.3% of warfarin users died compared with only 4.8% of nonusers (OR, 2.02; 95% confidence interval [CI], 1.95-2.10; P < .001). After adjusting for important covariates, warfarin use was associated with increased mortality among all patients (OR, 1.72; 95% CI, 1.63-1.81; P < .001) and patients 65 years and older (OR, 1.38; 95% CI, 1.30-1.47; P < .001). CONCLUSIONS Warfarin use is common among injured patients and its prevalence has increased each year since 2002. Its use is a powerful marker of mortality risk, and even after adjusting for confounding comorbidities, it is associated with a significant increase in death.