Candidate for the Lee B. Lusted Student Prize Competition
Purpose: A recent study of 223,475 severely injured patients transported from the scene to trauma centers found that helicopter transport was associated with a 15% relative risk reduction in mortality compared to ground ambulance transport. In 2010, 47% of U.S. helicopter scene transports had only minor injuries. We assessed the cost-effectiveness of helicopter transport given that overtriage of patients with minor injuries to helicopter transport does not improve their outcomes.
Method: Using a Markov model, we evaluated the cost-effectiveness of helicopter scene transport relative to ground transport given triage accuracy in current practice compared with the hypothetical case of perfect triage accuracy (all patients transported have severe injury). The model followed patients from injury through prehospital care, hospitalization, first year post-discharge, and the remainder of life. Patients were trauma victims (mean age: 43; range: 18-85) with Abbreviated Injury Scores (AIS) from 1-6. Costs and survival probabilities stratified by injury severity were derived from the National Study on the Costs and Outcomes of Trauma supplemented by the National Trauma Data Bank. Transport crash risks were derived from the published literature. Outcomes included costs (2009$), quality adjusted life-years (QALYs), and incremental cost-effectiveness ratios. We used second-order Monte Carlo simulations (10,000 samples) to estimate means and confidence intervals (CI) for all outcomes.
Result: With a 15% mortality reduction and current triage accuracy, helicopter transport costs $113,306 per QALY gained (95% CI: $98,732-131,544) compared to ground ambulance transport and is never dominated or cost-saving. If triage were performed perfectly, helicopter transport would cost $67,214 per QALY gained (95% CI: $59,799-75,700), a reduction of $48,201 per QALY gained. Assuming a 15% mortality reduction, overtriage of minor injury patients would have to be reduced from 47% to 31% for helicopter transport to have at least a 95% probability of costing less than $100,000 per QALY gained. Similarly, if current triage accuracy remains the same, the mortality reduction provided by helicopter transport would need to be greater than 19%.
Conclusion: Unless overtriage of patients with minor injuries can be substantially reduced from its current level of 47%, or mortality reductions for seriously injured patients transported by helicopter are greater than was found in a recent large observational study, as currently used, helicopter scene transport is not cost-effective relative to ground transport.