The impact of pre-injury anticoagulation therapy in the older adult patient experiencing a traumatic brain injury: A systematic review.

REVIEW QUESTION/OBJECTIVE: The objective of this systematic review is to synthesize the best available evidence on the impact of pre-injury anticoagulation therapy in the older adult patient who experiences a traumatic brain injury.

BACKGROUND

Trauma in the elderly remains one of the most challenging problems for healthcare providers in the 21 century. The most recent United States (U.S.) census estimates that by the year 2020 more than 52 million Americans will be age 65 years or older, and one million of those will live to be over 100 years of age. In the older adult population, classified as age 65 years or greater, the two leading causes of injury were reported as motor vehicle crashes (MVC) and falls. We have become increasingly aware of the unique physiologic changes in this population that make them more susceptible to succumb to traumatic injuries than their younger counterparts. This is especially true in the anticoagulated patient with a traumatic brain injury.Traumatic brain injury (TBI) is defined as an injury occurring when an external force traumatizes the brain. It may also be known as an intracranial or head injury. TBI is classified depending on the mechanism of injury (blunt or penetrating), severity, and location of the assault. Damage to the brain, skull, and/or scalp transpires. TBI is the leading cause of death and disability in the U.S, and persons of all ages, races, ethnicities, and incomes are affected. In the past five to ten years, trauma services have recorded an increase in major trauma admissions of patients age 65 years and older. In review of the literature to date, it is recognized that outcomes following moderate to severe TBI in older adults are poor, with high rates of significant disability and mortality reported. A recent Australian study reported that 28% of older adults died in the hospital following a TBI and in Finland adults aged 75 years and older had the highest rates of TBI related hospitalizations and death. According to a systematic review of European studies, the overall incidence of hospitalized TBI patients was 235 incidents/per 100,000 individuals, with a mortality rate of 15.4 deaths/per 100,000 of the population.The association between medications that alter a patient's coagulation function and adverse trauma outcome continues to be an important area of interest and study. The percentage of Americans on anticoagulant and antiplatelet agents continues to increase with the long-term trend towards longer life expectancies. Older adults are prescribed anticoagulants and antiplatelet agents to prevent thromboembolic complications of artial fibrillation; prosthetic cardiac valves; cerebral, coronary, and peripheral vascular disease; as well as several other medical conditions. One of the most frequently prescribed anticoagulant medications is warfarin. The prevalence of warfarin use in the Unites States is unknown, but the Food and Drug Administration (FDA) estimates that more than 31 million prescriptions were written in 2004. Newer, more potent antiplatelet medications like clopidogrel (Plavix) pose an even greater risk for uncontrolled bleeding in trauma patients. The uncertainty regarding the impact on trauma outcomes is compounded by the variable response of patients to anticoagulant or antiplatelet medication for an associated comorbidity. Evidence suggests that outcomes for TBI are worse, and there may be delayed intracranial hemorrhage in this population of patients.According to a Western Australian study, trauma patients are theoretically at risk for prolonged major bleeding. Studies of traumatic intracranial hemorrhage (ICH) suggest that patients taking anticoagulants have two to six times greater mortality. Mina et al. noted that the trauma patient with preinjury anticoagulation such as warfarin or even aspirin who had an intracranial injury had a four to five fold higher risk of death than the non-anticoagulated patient. Franko et al. concluded that mortality of patients over age 70 was significantly higher than that of younger patients when taking preinjury anticoagulants. The concern about unfavourable outcomes in the anticoagulated older adult patient presenting with traumatic injury has led many healthcare systems to take action. Ivascu et al. looked at early identification in triage for at- risk patients, and implemented warfarin (coumadin) protocols to assist in promoting improved patient outcomes; however, her research did not demonstrate a positive impact. In an effort to find a relationship between preinjury anticoagulation and outcomes in the older adult trauma patient, the degree of anticoagulation rather than the anticoagulant itself was studied to assist with predicting the severity of the TBI. Pieracci et al. concluded that among older adult patients who have sustained a head injury, warfarin use with an admission International Normalized Ratio (INR) greater than or equal to two was associated with an increase severity of TBI, a trend toward an increased likelihood of intracranial hemorrhage (ICH), increased overall mortality, and increased mortality after ICH.The impact of trauma- related morbidity and mortality in the elderly population is significant. Older adult patients account for 25% of trauma related hospital costs, 25% of trauma-related deaths, have the highest age-specific rate of TBI, and have worse outcomes reported. Fortuna et al. concluded that preinjury anticoagulants and antiplatelet medications used by the older adult patient were not associated with increased mortality, but age was a significant predictor of mortality. Research by Wojcik et al., concluded that preinjury anticoagulation therapy did not adversely impact mortality or length of stay (LOS) outcomes in the head injured patients.The influence of anticoagulation on outcomes in the older adult patient with a head injury has been studied, and has resulted in significant debate. Chronic use of anticoagulants and antiplatelet medications in the management of many medical conditions has increased over the decades. As a consequence, older adults over the age of 65 are at risk for trauma related injuries. Concomitant risks include bleeding after traumatic injury.What is known nationally and internationally is our population is aging. With an aging population comes acute and chronic illness. Anticoagulant medication is frequently prescribed for health conditions to promote positive patient outcomes. We know the impact of anticoagulant and antiplatelet therapy may have detrimental effects; especially when an older adult experiences a traumatic brain injury. What we don't know about the impact of anticoagulant and antiplatelet therapy is how it effects the trauma patient, how to rapidly and successful reverse the detrimental outcomes, and how to prevent mortality in this specific age group. A systematic review of the literature will synthesize the data, identify gaps, and recommend on-going research related to the impact of untoward outcomes in the older adult, anticoagulated, trauma patient.Theoutcome to be studied is mortality prior to discharge from the healthcare system. The gaps in the literature, timeliness of research, and change in demographic data justifies a systematic review of the literature to assist in providing consensus to base practice change, policy advances, and protocol development to promote positive patient outcomesPrior to the commencement of the review, a search of the Cochrane Library of Systematic Reviews, Joanna Briggs Institute (JBI) Library of Systematic Reviews, and MEDLINE was performed. No systematic reviews of the proposed topic were located.