Falls represent an enormous global public health burden associated with significant disability and mortality, with a worldwide age-standardized incidence of 2,238 falls per 100,000 persons per year in 2017, over 16.6 million years of life lost, and an average loss of 4% of one’s full health status from one fall (James et al., 2020). For the U.S., the Centers for Disease Control (CDC) reported 7.9 million unintentional injurious falls in 2019 that was associated with 131.5 billion USD in medical costs (WISQARS (Web-Based Injury Statistics Query and Reporting System) | Injury Center | CDC, 2023). Although falls affect all ages, the burden of falls in the U.S. is disproportionately borne by older persons, for whom falls are the leading cause of disability and functional decline (James et al., 2020; Panel on Prevention of Falls in Older Persons, American Geriatrics Society and British Geriatrics Society, 2011).
Research and policy attention has been primarily devoted to falls occurring indoors,(“Guideline for the Prevention of Falls in Older Persons. American Geriatrics Society, British Geriatrics Society, and American Academy of Orthopaedic Surgeons Panel on Falls Prevention,” 2001; Panel on Prevention of Falls in Older Persons, American Geriatrics Society and British Geriatrics Society, 2011) despite reports of outdoor falls accounting for 47–58% of all falls among community-dwelling adults (Li et al., 2006; Timsina et al., 2017). Risk factors for indoor and outdoor falls also tend to differ. Indoor falls are more likely to be influenced by personal risk factors, the indoor environment, and underlying health conditions (Schepers et al., 2017). Outdoor falls occur among more active individuals and are primarily influenced by outdoor environmental factors (Schepers et al., 2017). These associated outdoor environmental factors have included weather conditions (e.g., snow and ice or extreme heat) and the physical environment (e.g., uneven surfaces, slippery surfaces, stairs) (Timsina et al., 2017). However there remains limited understanding for the role of urban design and the environment on the risk of outdoors falls, especially for falls on streets and sidewalks, where 85% of outdoor falls requiring an Emergency Medical Services (EMS) response were found to occur (Rundle et al., 2023, 2024). Additionally, there is an abundance of literature addressing the risk factors for falls related to the older population, but even for this demographic subgroup, research studies for outdoor falls were far fewer (Chippendale et al., 2023), with substantially greater focus on person-level and indoor environment characteristics (e.g. home trip hazards) (“Guideline for the Prevention of Falls in Older Persons. American Geriatrics Society, British Geriatrics Society, and American Academy of Orthopaedic Surgeons Panel on Falls Prevention,” 2001; Montero-Odasso et al., 2022; Panel on Prevention of Falls in Older Persons, American Geriatrics Society and British Geriatrics Society, 2011). These major knowledge gaps have hampered the development of community-specific and person-centered prevention strategies to reduce the burden of outdoor injurious falls (Chippendale et al., 2017; Li et al., 2006).
A primary reason for the lack of evidence to determine environmental risk factors for outdoor falls, and particularly at the population-level, is limitations in the surveillance of falls. The three primary public health surveillance systems in the U.S. for fall-related injuries are the CDC’s Web-Based Injury Statistics Query and Reporting System (WISQARS), the Behavioral Risk Factor Surveillance System (BRFSS) and the National Health Interview Survey (NHIS) and yet none of these systems routinely provide data on the locations in which falls occur (Moreland et al., 2020; Timsina et al., 2017; WISQARS (Web-Based Injury Statistics Query and Reporting System) | Injury Center | CDC, 2023). While the NHIS has been used to examine outdoor falls, these analyses are 10–25 years old, likely because the location of the fall is determined by intensive coding of unstructured narrative texts, which makes use of these data cumbersome to analyze (Timsina et al., 2017). To improve the surveillance of outdoor falls, Rundle et al. (2023) developed a methodology to identify injurious falls by indoor versus outdoor location using EMS clinical and administrative data from the National Emergency Medical Services Information System (NEMSIS) (Rundle et al., 2023). Among the 1,854,909 injuries from falls that required an EMS response in 2019, 129,408 of these fall injuries were identified as occurring outdoors on streets and sidewalks, a number which is 70% higher than the number of pedestrians reportedly injured by automobiles (Li et al., 2006; National Highway Traffic Safety Administration, n.d.; Timsina et al., 2017). While establishing this surveillance method was a critical first step towards developing interventions to reduce outdoor falls, epidemiological data are needed to improve understanding of the public health and clinical burden of outdoor falls.
There are very few available studies to compare the severity of indoor and outdoor falls, with the focus of these being among the older adult population (Bath & Morgan, 1999; Chippendale et al., 2017; Kelsey et al., 2010, 2012; Kim, 2016; Lee, 2021; O’Loughlin et al., 1994). Chippendale et al.’s (2016) study of older U.S. trauma center patients who sustained outdoor falls had a higher frequency of open wounds and head injuries compared to indoor falls, but no significant difference on the injury severity score (ISS) (Chippendale et al., 2017). Kim (2016) found that outdoor falls led to a higher proportion of head and neck injuries than indoor falls among older emergency department patients across 20 hospitals in Korea (Kim, 2016). Jung et al. (2017) determined that the likelihood of severe injury, as determined by level of care, from outdoor falls in older adults was higher in men compared to women (Jung et al., 2018). These studies were limited by examining only individuals admitted to a hospital, and none were of a nationally representative sample. Furthermore, assessment of outcomes and severity of falls varied across these studies. Improved understanding of the clinical severity for fall injuries is critical to determining the short- and long-term burdens of 1) morbidities and disability among individuals (Stewart Williams et al., 2015) and 2) health care utilization needs of different communities (Eliacin et al., 2021; Korley et al., 2016), particularly in light of potential differences across sociodemographic groups (Chun Fat et al., 2019; Sharma et al., 2018). In the immediate setting following an injury, clinical severity scoring tools have been recommended, including the Revised Trauma Score for Triage (T-RTS) and Glasgow Coma Scale (GCS), to help guide on-scene EMS to determine the severity of the injury and optimal care response for the individual (Champion et al., 1989; Newgard et al., 2022). However, there are no population-level studies that have characterized the distribution of such scores in the assessment of severity of indoor versus outdoor injurious falls.
National surveillance data comparing indoor and outdoor injurious falls are critical to the development of person-centered, community-specific programs and policies to prevent serious falls. Data from EMS responses on the severity and level of care for indoor and outdoor injurious falls could be particularly informative from a healthcare resource perspective. Here we use 2019 national U.S. EMS data to compare the clinical trauma severity of indoor versus outdoor injurious falls, and further to examine these patterns by patient demographic characteristics.