A systematic review of the costs and benefits of helicopter emergency medical services

Introduction: Helicopter emergency medical services (HEMS) are popular in first world health systems despite inconsistent evidence in the scientific literature to support their use. The aim of the current study was to perform a systematic review of economic evaluations of HEMS, in order to determine the economic cost of HEMS and the associated patient-centered benefits. Method: A systematic review was performed of studies that provided a cost estimate of HEMS. The inclusion criteria consisted of English language articles that estimated both the costs and outcomes of a HEMS and fulfilled pre-specified criteria in relation to a cost analysis, cost-minimisation, cost effectiveness or cost-benefit evaluation. Identified studies were synthesised according to the patient diagnosis (trauma, non-trauma or non-specific) and the type of HEMS transport under review (primary scene retrieval or secondary inter-facility transport). All costs were converted to US dollars and indexed for inflation. Results: Fifteen studies met the inclusion criteria. Among all studies the annual cost of HEMS ranged from $115,777 to $5,571,578. Five studies showed HEMS to be a more expensive transport alternative without an associated benefit while eight studies provided cost-effectiveness ratios of $ 3292 and $ 2227 per life year saved for trauma, $ 3258 per life saved and $ 7138 and $ 12,022 per quality adjusted life year for non-trauma and $ 30,365 and $ 91,478 per beneficial mission for non-specific patient populations. One study also evaluated the cost of HEMS to societal benefit, producing a ratio of 1:6. Interpretation: The cost and effectiveness of HEMS varied considerably between studies. Despite generally being more expensive than ground transport, a number of studies found HEMS to be cost-effective. However, given the variation in the intervention design, context and study methods between studies it was not possible to assess the cost-effectiveness of HEMS in general. Given the variation inherent in the health systems in which HEMS operate, synthesis and extrapolation of study findings across differing health environments is difficult. To address economic and clinical evidence in relation to HEMS, future research that is tailored to account for local system factors is required. (C) 2009 Elsevier Ltd. All rights reserved.