International survey on willingness-to-pay (WTP) for one additional QALY gained: what is the threshold of cost effectiveness?



Although the threshold of cost effectiveness of medical interventions is thought to be £20 000–£30 000 in the UK, and $50 000–$100 000 in the US, it is well known that these values are unjustified, due to lack of explicit scientific evidence. We measured willingness-to-pay (WTP) for one additional quality-adjusted life-year gained to determine the threshold of the incremental cost-effectiveness ratio. Our study used the Internet to compare WTP for the additional year of survival in a perfect status of health in Japan, the Republic of Korea (ROK), Taiwan, Australia, the UK, and the US. The research utilized a double-bound dichotomous choice, and analysis by the nonparametric Turnbull method. WTP values were JPY 5 million (Japan), KWN 68 million (ROK), NT$ 2.1 million (Taiwan), £23 000 (UK), AU$ 64 000 (Australia), and US$ 62 000 (US). The discount rates of outcome were estimated at 6.8% (Japan), 3.7% (ROK), 1.6% (Taiwan), 2.8% (UK), 1.9% (Australia), and 3.2% (US). Based on the current study, we suggest new classification of cost-effectiveness plane and methodology for decision making. Copyright © 2009 John Wiley & Sons, Ltd.