In this study, we examined whether vulnerable population groups faced more difficult geographical access to trauma centers in 2005. Our findings from this cross-sectional analysis highlight that, in addition to the disparities in treatment care noted in the 2003 Institute of Medicine report,35
certain vulnerable groups appear to face system-level disparities of poorer geographical access to trauma centers in rural and urban areas. In particular, we found that areas with a higher proportion of certain groups, such as African American and near-poor populations in urban and rural areas and foreign-born population in urban areas, were at higher risk of having difficult access to trauma centers or, in other words, were farther away from trauma centers.
Our study has several limitations. First, the zip code–level census data are only available every 10 years. Therefore, it is possible that there will be measurement errors of our key independent variables because our dependent variable was based on 2005 data. However, given the unlikely occurrence of large shifts in zip code composition in 5 years, we do not believe that these slight deviations would significantly alter our results.
Second, although we used a previously described method to calculate distances and correlated this to travel time, driving times may be more variable, especially in rural areas.
Third, we used driving time to the nearest trauma center to define geographic access. It is important to remember that rural communities may have established relationships with aeromedical transport to urban trauma centers, and we may have overestimated the difficulty to access trauma services in those rural communities because we cannot account for aeromedical transport. However, it is unclear how many rural areas have negotiated agreements with other trauma centers for airlifting trauma patients. In addition, even in certain rural settings, the benefit of helicopter transport for most patients (especially those of lower severity) has been questioned36,37
; some literature suggests that the current “hub-and-spoke” model of air transport may be the best model for severely injured patients,38
especially when ground transport distance is greater than 45 miles (72 km).39,40
It is crucial to recognize that providing aeromedical transport and building a trauma center are expensive endeavors. Although more extensive discussion of these issues is beyond the scope of this study, it is important for future research to compare the cost-effectiveness of expanding the aerial transport network vs establishing trauma centers (which could include lower level trauma centers).
Finally, we examined only 1 type of access, namely, geographical access to the trauma centers. There are other barriers to care that we cannot address in this study, such as financial and cultural barriers in obtaining trauma care when needed. Persons in communities with easy geographical access to trauma centers still would face disparity in care if they are unable to overcome other types of barriers to care. For example, although we do not find that communities with a high share of Hispanic population face more difficult geographical access to trauma centers, language and cultural barriers still might prevent this population from obtaining timely access to the critical care. Likewise, although communities with high shares of families below the federal poverty line do not have a higher odds of living far away from trauma centers, they are likely to face financial barriers.
Overall, our findings point to a significant segment of the US population (representing 38.4 million people) who do not have access to trauma care within 30 miles (equivalent to 1 hour of driving). Moreover, access is uneven across communities, and certain vulnerable groups are at higher risk than others for worse access to trauma centers. The separate analyses for urban and rural areas show that the types of vulnerable subpopulations facing more difficult access are not identical between urban and rural communities. These findings suggest that there may be fractures in access to care on a system level and that evaluation of trauma center availability should take this type of disparity into consideration. Our research should not be interpreted to mean that trauma centers should be built in every small town across the United States, but rather that access in urban and rural settings is diminished for areas with higher proportions of minority populations and the poor, who may experience a higher burden of injury. Therefore, stakeholders and health care planners should therefore consider these factors in the development of trauma systems because a mismatch of potential need and access could signal inefficiencies in the delivery of care.