Searching for the social value of a QALY in the Netherlands: The Willingness to Pay for a QALY

Objective: the aim of this study was to elicit the social willingness to pay (WTP) for a Quality Adjusted Life Year (QALY) from the Socially-Inclusive Individual (SII) perspective in the Netherlands. Methods: Respondents valued a hypothetical health state scenario by means of a web-based contingent valuation exercise. The respondents first valued their own health state, using the EQ-5D profile, and were asked to rate their own health, perfect health, death and the hypothetical health state scenario on the Visual Analogue Scale (VAS). Furthermore respondents expressed their WTP for avoiding a decline in health from their own current health state (better) to the hypothetical health state scenario (worse) using a payment scale, followed by a bounded open contingent valuation question. Analysis: WTP per QALY was calculated for QALY gains using both VAS valuations, as well as the Dutch EQ-5D tariffs. Three different scenario’s were created in order to calculate QALY losses (i.e. QALY gains) due to premature death. Differences in WTP per QALY estimates were examined from the perspective of household income and the level of certainty in WTP expressed by respondents. Theoretical validity was analyzed using multivariate regressions. By means of a sensitivity analysis it was investigated whether expressed WTP was sensitive to scale. Results: 498 respondents, representative of the Dutch population, participated in the survey. Mean WTP per QALY was € 65,797 based on Dutch EQ-5D tariffs and € 65,194 based on VAS valuations. Incorporating discounting and a correction for age-related quality of life decline lead to much higher WTP estimates. WTP for a QALY was strongly associated with income, varying from an average of € 43,611 (EQ-5D) and € 43,211 (VAS) in the lowest income group to an average of € 84,505 (EQ-5D) and € 83,730 (VAS) in the highest income group. Regression analyses confirmed expected relations between WTP, size of the QALY gain, income, and some other socio-economic characteristics. Conclusion: Social WTP per QALY values elicited in this study are higher than those found in studies reporting individual WTP values. Social WTP for a QALY is a rather unexplored item and requires more research.