An economic evaluation of a new treatment modality for whiplash injuries sustained during road traffic crashes

Abstract

Background: Whiplash injures are the most common compensable injury following road accidents and are evidenced to burden health care systems with treatment costs. However, there is a gap in the literature on the economic efficiency of interventions targeting its management. Objective: The overall purpose of this thesis is to assess the economic efficiency of clinical interventions aiming to improve health outcomes after compensable whiplash injuries in Australia. Methods: The thesis uses the setting of a trial (ACE; Accident Care Evaluation) investigating the effect of an early intervention on the health status of people with mild to moderate whiplash injuries following road traffic crashes in the Australian Capital Territory. The thesis is concerned with how the benefits are quantified. The thesis therefore investigates two types of economic evaluation techniques: the cost-benefit (CBA) and the cost-utility (CUA) analyses. Both techniques rely on the distinct economic theories of welfarism versus extra-welfarism for guiding decision-making in the health. The thesis is structured around three major arguments. First, the current approaches to quantification of health outcomes using the quality-adjusted life-year can introduce limitations in providing accurate and generalisable results. Second, compensation payments have the potential to be used as a proxy for the monetary value society is willing to place on a unit of improvement in health, while representing a state of equilibrium between supply and demand points of view. Third, the choice of economic evaluation technique -and its underlying theoretical concept-for the assessment of clinical trials may have some implications on the consequential recommendations. Following this argument, the thesis investigates the hypothesis that cost-benefit analysis with its roots in welfarist economic theory should be the preferred method for priority setting in the context of compensable whiplash injuries. The thesis consists of several analyses; a systematic review was conducted to assess the current literature on economic evaluations of trials of whiplash management, and an analysis of the costs of the ACE trial, which was then used as a component of the economic evaluation. Three analyses were performed using the health outcomes, costs and compensation data. First, health state utility values were derived using two leading health state utility instruments - EQ-5D and SF-6D, which are tested for interchangeability within the international and Australian contexts. Secondly, compensation awards are analysed to derive a monetary threshold for society's willingness to pay for each unit of improvement in health -a monetary value for one QALY. Thirdly, two types of economic evaluations are performed: CUA and a CBA to compare the resulting policy implications. Results: The findings of the thesis demonstrate that there is acceptable agreement between the EQ-5D and SF-6D when deriving QALY gain estimates, but may lead to significantly different cost per QALY estimates. The cost-benefit analysis resulted in a net monetary benefit and some cost savings. The analysis provided an initial value for the monetary value of one QALY for Australia using the compensation payments theory. Conclusion: This thesis contributes to the field of economic evaluation in health by providing empirical evidence of the slight but significant inconsistencies in the use of stated preference methods for valuation of health outcomes. The thesis also proposes the use of compensation awards as a method of quantification of health benefit for the purposes of the economic assessment of compensable injuries and highlights the added value of using a cost-benefit analysis approach as a possible methodology of choice in the context of priority setting in health care interventions targeting compensable injuries and more generally advocates for the welfarist approach in economic evaluation in health. Show more