Willingness to pay per quality-adjusted life year in a study of knee osteoarthritis

Background. Determining whether a particular medical intervention is cost-effective requires that a threshold of cost per benefit gained be established. As debate continues over the appropriate threshold, we present measures of willingness to pay (WTP) per quality-adjusted life year (QALY)for own health and 2 hypothetical osteoarthritis scenarios. Methods. One hundred ninety-three persons, located through random digit dialing in Harris County, Texas, completed face-to-face interviews collecting demographic information and health preferences using visual analog scale, time tradeoff, standard gamble, and WTP methodologies. Results. The mean WTP/QALY for all methods was lower (range, $1221-$5690/QALY) than many estimates from revealed preference studies and lower than the oft-cited arbitrary cutoff of $50 000. WTP/QALY was highest when participants were judging their personal health improvements as opposed to hypothetical scenarios. There were some significant differences in WTP/QALY across elicitation methodologies for the some scenario. Demographic characteristics were not associated with WTP/QALY measures. Conclusions. The health states and improvements in health evaluated here do not contain a risk of mortality, unlike many situations in which WTP/QALY has been previously evaluated, The lower WTP/QALY values found here may indicate that the presence of a mortality risk reduction substantially increases stated WTP/QALY Appropriate thresholds for cost-effectiveness maybe dependent on the context of a situation, including risk of mortality.