Cost-Effectiveness of Helicopter Versus Ground Emergency Medical Services for Trauma Scene Transport in the United States

Study objective

We determine the minimum mortality reduction that helicopter emergency medical services (EMS) should provide relative to ground EMS for the scene transport of trauma victims to offset higher costs, inherent transport risks, and inevitable overtriage of patients with minor injury.

Methods

We developed a decision-analytic model to compare the costs and outcomes of helicopter versus ground EMS transport to a trauma center from a societal perspective during a patient's lifetime. We determined the mortality reduction needed to make helicopter transport cost less than $100,000 and $50,000 per quality-adjusted life-year gained compared with ground EMS. Model inputs were derived from the National Study on the Costs and Outcomes of Trauma, National Trauma Data Bank, Medicare reimbursements, and literature. We assessed robustness with probabilistic sensitivity analyses.

Results

Helicopter EMS must provide a minimum of a 15% relative risk reduction in mortality (1.3 lives saved/100 patients with the mean characteristics of the National Study on the Costs and Outcomes of Trauma cohort) to cost less than $100,000 per quality-adjusted life-year gained and a reduction of at least 30% (3.3 lives saved/100 patients) to cost less than $50,000 per quality-adjusted life-year. Helicopter EMS becomes more cost-effective with significant reductions in patients with minor injury who are triaged to air transport or if long-term disability outcomes are improved.

Conclusion

Helicopter EMS needs to provide at least a 15% mortality reduction or a measurable improvement in long-term disability to compare favorably with other interventions considered cost-effective. Given current evidence, it is not clear that helicopter EMS achieves this mortality or disability reduction. Reducing overtriage of patients with minor injury to helicopter EMS would improve its cost-effectiveness.

Introduction

Trauma is the leading cause of death for US residents aged 1 to 44 years, is the most common cause of years of life lost for those younger than 65 years,¹ and exacts $406 billion per year in costs, more than heart disease or cancer.2, 3 Survival after trauma is improved by timely transport to a trauma center for severely injured patients.⁴ Helicopter emergency medical services (EMS) offers faster transport than ground EMS for patients injured far from trauma centers and is considered a preferred means of transport for critically injured patients.⁵ Approximately 27% of US residents are dependent on helicopter transport to access Level I or II trauma center care within the “golden hour” from injury to emergency department (ED) arrival.⁶ However, there are conflicting data to support routine use for scene transport. Most studies have concluded that helicopter transport was associated with improved survival,7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 whereas others showed no difference.24, 25, 26, 27, 28, 29, 30 These studies have methodological limitations and selection bias, missing physiologic data, and heterogeneity in study settings and observational study designs.

In 2010, there were more than 69,700 helicopter transports for trauma to US Level I and II trauma centers; 44,700 (64%) were from the scene of injury.³¹ According to the Medicare Fee Schedule, insurance companies reimburse $5,000 to $6,000 more per transport than ground ambulance, which means $200 to $240 million more was spent with this modality for trauma scene transport in 2010.³² Furthermore, a systematic review has shown than more than half of the patients flown have minor or non–life-threatening injuries that would likely have similar outcomes if transport were by ground.³³ Helicopter transport also may present a safety risk. In 2008, medical helicopter crashes caused 29 fatalities, the highest number to date, provoking federal review of the safety of air medical transport.³⁴ Currently, there is little empirical guidance on whether the routine use of helicopter EMS for trauma scene transport represents a good investment of critical care resources.

Given the limitations of the helicopter EMS outcomes literature, we aimed to determine the minimum reduction in mortality or long-term disability provided by helicopter EMS for its routine use to be considered cost-effective over ground EMS for the transport of patients from the scene of injury to a trauma center. We assessed these clinical thresholds relative to current evidence about effectiveness of helicopter transport. In this study, we account for transport costs and safety, as well as the inevitable overtriage of patients with minor injuries to helicopter transport.