Effect of preinjury warfarin use on outcomes after head trauma in Medicare beneficiaries

Abstract

BACKGROUND: Elderly Americans are at increased risk of head trauma, particularly fall related. The effect of warfarin on head trauma outcomes remains controversial. METHODS: Medicare beneficiaries with head injuries from 2009 to 2011 were identified by International Classification of Diseases (ICD)-9 code. Preinjury warfarin use was determined using Part D claims. Multiple logistic regression models determined the association of preinjury warfarin on need for hospitalization, intensive care unit care, and occurrence of intracranial hemorrhage. Association between warfarin and in-hospital mortality was assessed using a Cox proportional hazard model. RESULTS: Of 11,078 head injured patients, 5.2% were injured while on warfarin. Preinjury warfarin increased the odds of intracranial hemorrhage by 40% and doubled the risk of 30-day in-hospital mortality after adjusting for demographic and clinical factors. CONCLUSIONS: Warfarin at the time of head injury increases the risk of adverse outcomes in Medicare beneficiaries with head injuries. Caution should be used when initiating anticoagulation in elderly Americans at risk for trauma.