A Mixed Method Approach to Estimating Monetary Values of QALYs

Introduction: The health care budget in the UK is finite and, as such, decisions must be made about how best to allocate scarce resources. Cost effectiveness analysis, and its overall summary measure of cost per quality adjusted life year (QALY) gained from an intervention, is used as part of the decision as to which interventions are recommended for adoption by the NHS. However, there is no empirically established point at which the cost per QALY becomes too high. The lack of any definitive decision rule raises the question of what is the monetary value of a QALY. Within the health economics literature the focus on developing a monetary value of a QALY for use in policy making has been on developing a single value which can be applied to all health care interventions. This is based on the assumptions of the underlying QALY model which assumes that all QALYs are equal no matter what the combination of quality of life and life expectancy. However, there is evidence to suggest that this may not coincide with how people value the trade-offs between quality of life and life expectancy. Objectives: The objectives of this paper are to determine whether the monetary value of a QALY will vary according to 'QALY type' (i.e. whether the QALY gain arises because of a change in quality of life or a change in life expectancy) using two different methodologies. Methods: Two different methods were used to estimate monetary values of QALYs gained via three different types of the health care intervention; treatments which improve quality of life only, those which increase life expectancy only and treatments which are life saving. The first stage of the research was to model values of QALYs using the Department for Transport's value of a prevented fatality (VPF) and value of a serious injury (VSI). In the second phase five willingness to pay (WTP) questions were designed to directly elicit WTP per QALY values from members of the public. The results of the WTP study were supplemented with qualitative information from respondents about their opinions on priority setting in health care in the UK and the types of interventions that should be funded and in particular what characteristics of these interventions may be driving their choices. The qualitative data was generated using Q methodology, which uses a card sort exercise as a basis for understanding people's opinions about a topic. Results: The results indicate that WTP per QALY values do vary according to QALY type. The results of the modelling study produced estimates in the range ¿6,000-¿64,000 and the direct WTP study produced results ranging from ¿1,600-¿27,000. The WTP per QALY values for life saving interventions were higher than those estimated for interventions which are life extending only or quality of life enhancing. The results of the Q study indicated that the components of the QALY were important in decision making process, with life-saving interventions given higher priority than those which improved only quality of life or life expectancy