The relationship between state-level funding, designated trauma centers, and trauma-related mortality

Introduction

In the United States, the leading cause of death in the first four decades of life is related to traumatic injury (1). The number of traumatic injuries in the U.S. is rising annually and is responsible for more than 42 million emergency room visits, 2 million inpatient admissions, and over $406 billion of expenditures related to the care of injured patients as of 2013 (2). Early treatment at a designated trauma center with the level of services available to meet the patient’s needs has been shown to improve outcomes for the injured patient (3).

Levels designate trauma centers according to their services to the injured patient (4). Level 1 trauma centers provide the highest level of care to the injured patient and are typically associated with a university that supports research and residency teaching. Level 2 trauma centers are part of a more extensive trauma system and provide similar care to a Level 1 trauma center except for highly specialized care in subspecialty areas. They are typically located in less populated but urban areas. Level 3 trauma centers provide stabilization and/or emergent surgery to an injured patient; approximately two-thirds are located in rural areas. Finally, Level 4 trauma centers are located in rural areas, and their role is to assess, stabilize, and transfer the injured patient to the closest, most appropriate facility that can manage their trauma needs.

Patients with severe trauma injuries require the highest level of trauma care available and rapid coordinated transport to the nearest Level 1 or 2 trauma center (5). In a meta-analysis of the trauma literature, Celso and colleagues (6) found a 15% reduction in mortality for trauma injured patients treated at trauma centers within established trauma systems. In addition, multiple germane studies have shown reduction in both mortality and morbidity when patients receive trauma care at Level 1 and Level 2 trauma centers in a timely manner and do not have to travel long distances to access these higher levels of care (7-9). Furthermore, national studies on trauma systems and subsequent trauma mortality demonstrate the same reduction in overall trauma mortality of 25% when patients are treated in an inclusive regionalized trauma system (10).

Due to the lack of federal funding for coordinated regionalized trauma systems, trauma centers either depend on state funding, which varies considerably across states, or are self-funded through other sources. As such, the greatest threat to sustaining trauma systems’ ability to provide regional organized care is financial insecurity (11). The financial challenges are driven by several factors inherent with the provision of trauma services (12). Designated trauma centers have high fixed-cost structures associated with readiness costs to meet the needs of severely injured trauma patients and comply with the quality standards of the American College of Surgeons Committee on Trauma (ACS-COT) that require the availability of highly trained personnel activated before the trauma patient arriving to the trauma center (13). In addition to the high fixed cost of trauma centers, approximately 20% of trauma patients are uninsured at the time of their injury (12).

Many Level 1 trauma centers are found within safety-net hospitals that serve a vulnerable population who are more likely to be uninsured or underinsured, putting additional financial pressure on the trauma center to cover the fixed costs associated with 24/7 readiness required at high-level designated trauma centers (14). Safety-net hospitals depend on additional subsidies such as disproportionate share hospital payments to help offset operational losses to continue to provide the Level 1 care required for trauma patients, especially in the absence of state-level funding dedicated to trauma system services (14). Therefore, the risk of trauma center closure due to financial hardship is greatest for safety-net hospitals, whether located in an urban or rural setting (15).

In the absence of federal funding for regionalized trauma systems, some states (n=18) have tried to close the funding gap needed to sustain trauma systems in their states by providing funding directly to designated trauma centers (2,16). Relatively little is known, however, about whether these efforts have financially strengthened trauma systems to support their ability to improve trauma patient outcomes.

The purpose of this study was to examine the relationship between state-level funding, the number of trauma centers within a state, and trauma-related mortalities. More specifically, our hypotheses were:

• Hypothesis 1: there is a significant positive association between state-level funding and the number of trauma centers in a state.
• Hypothesis 2: there is a significant negative association between the number of trauma centers and trauma-related mortality.

Methods

Data sources

We used multiple data sources. Since a national database that captures state-level trauma does not exist, each lead agency responsible for the provision of trauma services at the state level was contacted by phone or email to inquire about the amount of monies paid to hospitals within their state, in the aggregate, and by year for the years 2008 to 2017 for the care of trauma patients. Funding amounts for the year 2008 for the state of Illinois and 2011 for the state of West Virginia were unobtainable. Thirty-two states had no funding from the state provided to designated trauma hospitals for readiness costs or uncompensated trauma care costs, while 18 states provided such funding. When the lead agency could not provide the information, a request for the information was made under the Freedom of Information Act from the appropriate state agency. State-level funding information was obtained for all 50 states during the study period.

The number and levels of designated trauma centers per state per year were obtained from the American Hospital Association (AHA) annual surveys. Trauma-related mortality data, using International Classification of Diseases 10^th Revision (ICD-10) trauma codes, were collected from the Centers for Disease Control and Prevention (CDC) web-based injury statistics query and reporting system (WISQARS) database. The data were available for all injury deaths and rates per 100,000 for all races, both sexes, and all ages. The Kaiser Family Foundation website provided data related to Medicaid expansion (control variable) by state for the study period. Population by state per year was collected from the WISQARS database.

Statistical analysis

Our study’s unit of analysis was the state. Fixed effects panel regression analysis was used to test both relationships: (I) state-level funding (paid to the designated trauma hospitals) and the number of trauma centers in a state, and (II) the number of trauma centers in a state and trauma-related mortality.

For hypothesis one, state-level funding was the independent variable, and the dependent variable was the number of log-transformed designated trauma centers in a state. The independent variable was operationalized as dollars per year paid (in million-dollar units) directly to hospitals to care for trauma patients at the state level. As a supplementary analysis, the total number of designated trauma hospitals as a dependent variable was further broken down into the number of hospitals within each of the four trauma level designations and then regressed against state-level funding to examine the relationship between the number of hospitals with different trauma level designations and state-level funding. Medicaid expansion, time dummy variables, and state-fixed effects were also included as control variables.

For hypothesis two, the independent variable was the total number of designated trauma centers. The independent variable was operationalized as the number of hospitals reporting they were a designated trauma center on the AHA survey per state. The dependent variable was the number of age-adjusted trauma-related deaths. Temporal trends were accounted for with year dummy variables. As a supplementary analysis, the total number of designated trauma hospitals as a dependent variable was divided into the number of hospitals within each of the four trauma level designations and then regressed against trauma-related mortality to examine the relationship between hospitals’ trauma designated level and the number of age-adjusted trauma-related deaths.

All variables were constructed separately for each year of the study, and analyses were conducted using STATA version 17.0. The Institutional Review Board of the University of Alabama at Birmingham approved this study as not human subjects research.

Results

Thirty-two states provide no funding to designated trauma hospitals for readiness costs or uncompensated trauma care costs while 18 states provide some level of funding directly to designated trauma hospitals. The results are reported at the start of the study period and the end of the study period to better understand the changes over the 10-year period.

Table 1 provides the descriptive statistics of our study’s population. The total number of trauma hospitals in 2008 ranged from 2 to 221 hospitals with an average of 30.6 trauma hospitals per state. In 2017, the number of trauma hospitals ranged from 1 to 239, with the average increasing to 33.44 per state. In 2008, the number of level 1 trauma hospitals in a state ranged from 0 to 28, with an average of 5.52 per state. In 2017, the range in the number of Level 1 trauma hospitals was 0 to 24 with an average of 5.28 per state. Level 2 trauma hospitals followed the same pattern showing a range of 0 to 42 hospitals in 2008 and an average of 8.64 hospitals per state; in 2017, the range was 0 to 37 with an average of 7.56 hospitals per state. Level 3 trauma hospitals followed the same pattern across the study period. In 2008, the range for Level 3 trauma hospitals was 0 to 127 with an average of 13.84 per state. In 2017, the range was 0 to 81 and an average of 11.48 Level 3 trauma hospitals per state. Level 4 trauma hospitals in contrast increased over the time period studied. In 2008, the range was 0 to 61 with an average of 2.26 per state. In 2017, the range was 0 to 117 and an increase in the average, to 8.40 Level 4 trauma hospitals per state. The age-adjusted mortality rates in 2008 ranged from 37.8 to 101 per 100,000 with an average rate of 64.18 per 100,000. The range increased over the 10-year period from 48.66 to 130.80 per 100,000 in 2017, with an average of 78.82 per 100,000. State funding of trauma hospitals increased over the study period. The state funding of trauma hospitals’ range in 2008 was $0 to $25,700,000 with an average of $3,145,677 compared to a range of $0 to $54,600,000 in 2017 with an average of $4,234,581.

Table 2 provides the results of the fixed effects panel regression analyses used to test Hypothesis 1, “Does a significant positive association exist between state-level funding and the number of trauma centers in a state?” We found that state-level funding for trauma care was not significantly associated with the number of trauma hospitals for a given state. With respect to the control variables, Medicaid expansion and time were not significantly associated with the number of trauma hospitals.

Our supplemental analysis revealed statistically significant findings for Level 1 and Level 4 trauma hospitals but not for Level 2 and Level 3 trauma hospitals. First, relative to the period before expanding Medicaid, we found a statistically significant increase (23%) in the number of Level 1 trauma hospitals (b=0.22976, P=0.01) within states that did expand Medicaid. In addition, relative to 2008, we found a statistically significant decline (19.4%) in the number of Level 1 trauma hospitals in 2017 (b=−0.19406, P=0.03). On the other hand, relative to 2008, there were statistically significant increases in the number of Level 4 trauma hospitals from 2009 to 2017, with a range of 55.1% (b=0.55138, P<0.001) to 152% (b=1.5180, P<0.001).

Table 3 provides the data from the fixed effects panel regression analyses used to test Hypothesis 2, “Does a significant negative association exist between the number of trauma centers and trauma-related mortality?” We found that the number of designated trauma hospitals were not significantly associated with trauma-related mortality. Relative to 2008, there was a statistically significant decrease of 2.4 points (P<0.001) and a statistically significant increase of 14.9 points (P<0.001) in 2009 and 2017, respectively in age-adjusted trauma-related mortality rates.

Our supplemental analysis revealed that each additional Level 3 trauma hospital in a state reflected a statistically significant increase of 0.19 point (P=0.03) in the age-adjusted trauma-related mortality rate. On the other hand, each additional Level 4 trauma hospital in a state was associated with a 0.25-point decrease in the age-adjusted trauma-related mortality rate (P<0.001). Levels 1 and 2 trauma hospitals were not significantly associated with age-adjusted trauma-related mortality rate. Across all regressions, there was a similar pattern of decreases in age-adjusted trauma-related mortality rate in 2009 and 2010, but increases in the trauma-related mortality rate from 2014 to 2017 relative to 2008.

Discussion

The purpose of this study was to examine the relationship between state-level funding, the number of trauma centers within a state, and trauma-related mortalities. Our first hypothesis, which examined whether a significantly positive relationship existed between the number of designated trauma hospitals and state-level funding, was not statistically supported by the analysis when considering the variable of total trauma hospitals. Our second hypothesis examining whether a significantly negative association existed between the number of trauma hospitals and trauma-related mortality was not supported when considering the variable total trauma hospitals or Level 1–4 trauma hospitals. The supplemental analysis partially supported our second hypothesis in regard to Level 4 trauma hospitals and the reduction in mortality, which is further explained below.

The first significant finding of this study was the change in the number of Level 1 trauma hospitals in Medicaid expansion states as compared to non-expansion states. We found that additional funding for trauma care in alternate forms, such as Medicaid expansion, can impact the number of trauma hospitals available for injured patients. States that expanded Medicaid saw a 23% increase in the number of Level 1 trauma centers as compared to the pre-expansion period. Level 1 trauma centers are more likely to receive a higher number of underinsured and uninsured trauma patients in transfer from lower-level trauma centers. “The hospitals that stand to gain the most from insurance coverage expansion are those that are already caring for the highest proportion of uninsured and minority patients” [(12), p. 9]. The revenue stream from Medicaid is one of the primary drivers of positive operating margins for trauma centers that are considered safety-net hospitals (12). The total number of trauma hospitals in each of the different level designations declined over the study period, with the exception of the Level 4 trauma hospitals. The decision to either contract or discontinue trauma services in the higher designation categories (Levels 1–3) is most often due to financial concerns driven by high numbers of uninsured, difficulty maintaining the needed specialists on call, or competitive market forces in densely populated urban areas. Whereas, Level 4 trauma hospitals require less financial and clinical resources and play an important role in filling the gap in access to care for trauma patients across geographically diverse parts of the country.

The second significant finding was the relationship between the number of trauma hospitals and age-adjusted mortality rates in Level 3 and 4 trauma hospitals. The number of Level 3 trauma hospitals in a state was associated with a 0.19-point increase per 100,000 in age-adjusted mortality rate. These results may reflect that Level 3 trauma centers’ role in the trauma system is the resuscitation and transfer of patients to Level 1 or 2 trauma centers as needed (17). The reasons for this small increase in age-adjusted mortality rate are likely multi factorial but suggest the resuscitation of trauma patients at a Level 3 trauma could be a factor. If trauma patients are undertriaged to a Level 3 trauma center, an increased age-adjusted mortality rate is a possibility due to delay in transfer to a higher-level trauma center. The number of Level 4 trauma hospitals in a state was associated with a 0.25 point per 100,000 population reduction in overall age-adjusted mortality rate. The increase in trauma services and stabilization of severely injured patients in geographically remote areas improves access to the highest level of care for trauma patients. It improves stabilization and transfer to higher-level trauma hospitals.

Time showed a consistent pattern in its relationship with age-adjusted mortality, whereby there was an initial decline in the age-adjusted mortality rate at the beginning of the study period, followed by an increase in the age-adjusted mortality rate by the end of the study period. Trauma-related related deaths have been on the rise at rates that are not explained with population growth (18). The trimodal peaks in mortality were seen with the age brackets of the 20s, 40s and 80s with possible causes including increasing violence, suicides, and comorbid conditions, respectively (18).

Limitations

As with all studies, this study has limitations. First, a limitation in this study was that some states provide a myriad of alternative subsidies or reimbursement enhancements that were not captured in the state-level funding variable that could impact the number of designated trauma centers in any one state. The second limitation relates to various mortality statistics issues, such as (I) mortality data do not take into consideration patients that arrive to the designated trauma center that have non-survivable injuries or that die at the scene of the accident, and (II) higher-level designated trauma hospitals receive the more severely injured and receive more patients with non-survivable injuries. To control for these and other challenges would require access to data at the patient level. Our data were limited to state level reported mortality rates. Likewise, future research could build on our findings by considering how individual-level factors (e.g., decision-making preferences, disciplinary background of decision-makers) may influence decisions to initiate or change trauma center designation. Similarly, our interest in this initial study was on all-cause trauma, and future research could extend this work by examining specific types of trauma mortality (e.g., motor vehicle accidents, gunshot wounds) to better account for the different causes and likelihood that hospitals may be providing trauma care. The study’s third limitation relates to the self-reported designation of trauma centers’ levels. Although the ACS-COT defines the criteria for the various trauma centers’ levels, there is no consistent approach among the states on the designation of trauma centers. Level 1 and Level 2 trauma centers are most closely aligned in states with the requirements outlined by the ACS-COT, but a great deal of variation exists in the process of achieving the designation from state to state. Some states require ACS verification of criteria to achieve state designation as a trauma center, especially as a Level 1 or 2 trauma center. This type of verification process is rigorous and can be cost-prohibitive for smaller hospitals in order to comply with all the criteria outlined in the ACS-COT requirements and could discourage hospitals from designation or participating at lower levels. In contrast, the designated hospitals that meet ACS verification have more rigorous quality standards designed to produce better patient outcomes. A final limitation is the number of observations that could be included in our analysis. Specifically, the statistical power of our analysis constrained our interest in state-level relationships. We tried to mitigate this limitation by using a longitudinal data set, but future research could extend our work by using different analytic designs that may enhance the explanatory power (e.g., growth curve models and qualitative methods).

Conclusions

State-level funding as a direct payment source was not found to have a significantly positive relationship with the number of total trauma hospitals. Currently, only 18 states in the U.S. fund designated trauma hospitals directly. Medicaid expansion did have a significant impact on the number of designated trauma hospitals by increasing the number of Level 1 trauma hospitals, which provide the highest level of care for trauma patients. Medicaid expansion, as an alternate source of state funding, may have a positive impact on the number of designated trauma hospitals available for the care of injured patients. The increasing trauma mortality rate over the study period and the decline in the number of higher-level designated trauma centers are concerning trends that warrant continued study by researchers. In addition, this study provides support for continuing discussions to urge policymakers to consider, at a minimum, alternative funding of inclusive regionalized trauma systems for improving both access to and quality of care for trauma-injured patients.

Acknowledgments

This study was presented at the 52^nd annual meeting of the Western Trauma Association, March 5–10, 2023 in Lake Louise, AB, Canada.

Funding: None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Journal of Hospital Management and Health Policy for the series “Healthcare Finance: Drivers and Strategies to Improve Performance”. The article has undergone external peer review.

Data Sharing Statement: Available at https://jhmhp.amegroups.com/article/view/10.21037/jhmhp-24-17/dss

Peer Review File: Available at https://jhmhp.amegroups.com/article/view/10.21037/jhmhp-24-17/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jhmhp.amegroups.com/article/view/10.21037/jhmhp-24-17/coif). The series “Healthcare Finance: Drivers and Strategies to Improve Performance” was commissioned by the editorial office without any funding or sponsorship. N.A.B. served as the unpaid guest editor of the series. L.R.H. serves as an unpaid editorial board memeber of Journal of Hospital Management and Health Policy from December 2022 to November 2024. The authors have no other conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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