Introduction
Older adults (≥65 years) are the fastest-growing age group in the United States. This population is projected to increase by 105% from 2015 (47.8 million people) to 2060 (98.2 million people), which will represent nearly one quarter of the US population.1 Traumatic injury and mortality in older adults are following the same trend, with falls representing more than half (55%) of unintentional death by injury in older adults in the United States.2 Treating traumatic injuries in this population has intrinsic challenges because of concomitant preexisting medical conditions and polypharmacy, which have important implications for field triage, inpatient care, and long-term functional outcomes after trauma.3 Trauma care systems need to evolve accordingly to meet the growing burden of older adult trauma, yet limited resources are currently used to better understand and improve trauma care outcomes for older adults.Editor’s Capsule Summary
What is already known on this topic
Injured older adults are less likely than younger ones to receive care in a trauma center.
What question this study addressed
What characteristics are associated with nontrauma center care (ie, undertriage) among older adults?
What this study adds to our knowledge
Among 7.8 million injured Medicare patients (2009 to 2014), 74% of all patients and 46% of severely injured ones were treated in a nontrauma center. Undertriage was more common in the South and West, among the oldest patients, and among patients living farther from trauma centers.
How this is relevant to clinical practice
Improving trauma center access for injured older adults may require both changes in out-of-hospital procedures and additional infrastructure or transportation capacity.
The most recent Centers for Disease Control and Prevention (CDC) guidelines for field triage of injured patients,4 updated in 2011, call for the highest level of care within the trauma system for patients meeting criteria. Level I and II trauma centers provide such care and offer definitive care for all injured patients. Moreover, the American College of Surgeons Committee on Trauma (ACS-COT) benchmarked the use of Injury Severity Score (ISS) greater than or equal to 16 nationally to define the patient population who would benefit from treatment at a Level I or II trauma center.5 Table 1 outlines key differences among trauma center levels of designation.6 These guidelines acknowledge undertriage as a problem and include special considerations for older adults because of elevated risk of poor injury outcomes. Such considerations include different thresholds for systolic blood pressure indicative of traumatic shock (≤90 mm Hg for adults <65 years and ≤110 for older adults) and increased priority for low-impact mechanisms (eg, ground-level falls). Trauma center care has been shown to lead to increased probability of survival in older adult trauma patients.7 However, several studies suggest that older adults may not fully benefit from advanced trauma care systems in the United States because numerous older adult patients are undertriaged to nontrauma centers.8, 9, 10, 11 Reported undertriage rates are variable and range from 33% to 49.9% in regional8 and multiregional10, 12 studies, with mixed findings on mortality and complications.9, 10, 13 There are 2 national studies of undertriage to our knowledge,11, 14 1 of them focusing on older adults.11 Both used encounter-level data from the Nationwide Emergency Department Sample,15 which has several key limitations related to triage decisions, including lack of information on mode of out-of-hospital transportation and the inability to determine the source of definitive care for transfer patients.
Across the United States, Medicare covers approximately 46 million Americans aged 65 years or older,16 regardless of income or health status, and therefore provides a unique analytic vantage point to better understand traumatic injury in a national sample of older adults.17 Studying undertriage among Medicare beneficiaries allows validation of previous estimates of undertriage and identifies potential determinants of undertriage, including mode of transportation and transfer status. These factors may be sensitive to policy interventions designed to ensure quality and efficiency of care as trauma health care systems grow and adapt to meet the increasing demand for services.
Our objective was to identify predictors of undertriage for older injured patients at a national level, identify any regions in which undertriage is more likely to occur, and examine additional factors associated with undertriage. We hypothesized that patient, injury severity, and geographic characteristics independently predict treatment by trauma center level.