Purpose: Trauma is the leading cause of death among Americans aged 1-44. Survival can be enhanced by prompt transport to trauma centers. Compared to ground ambulance transport, helicopters can further shorten transport times and provide a higher level of care. However, recently, concerns have been raised about the safety and high costs of helicopter trauma transport. The objective of this study is to determine the required mortality reduction achieved by helicopter transport of trauma victims from the scene of injury to a trauma center to justify their higher costs.
Method: We developed a decision-analytic Markov model to compare the costs and outcomes of two strategies: helicopter vs. ground ambulance transport from scene of injury to a Level I trauma center when expected ground transport time is >30 minutes. The model follows patients from injury through transport, during their hospitalization and first year post-discharge, and until death. We applied the model to a population of trauma victims (age 18-85 with serious injury (Abbreviated Injury Score [AIS] >=3) treated at U.S. Level I trauma centers based on the National Study on Costs and Outcomes of Trauma (NSCOT), with transport costs and safety data derived from the published literature. The analysis was conducted from a societal perspective over a lifetime horizon. The primary outcome measure is the threshold relative risk (RR) reduction in inpatient mortality by helicopter transport needed to achieve incremental cost-effectiveness ratios (ICER) of $50,000 and $100,000/QALY compared to ground transport. We assessed robustness with one-way sensitivity and probabilistic sensitivity analyses.
Result: Helicopter trauma transport must provide a 5% RR reduction in mortality for patients with mean characteristics of the NSCOT cohort to achieve an ICER below $100,000/QALY and a reduction of 12% to be below $50,000/QALY. Greater RR reductions are needed for less severely injured and older patients. However, very slight improvements in long-term disability outcomes for helicopter transport would reduce the RR reduction needed for cost-effectiveness. Results were relatively insensitive to the risk of fatal helicopter crash or to helicopter transport costs.
Conclusion: Compared to ground ambulance transport, helicopter transport is cost-effective if the relative risk of death can be reduced by more than 5% in seriously injured patients. Further study of the effectiveness of helicopter transport, especially of long-term disability outcomes, is warranted.
Candidate for the Lee B. Lusted Student Prize Competition