Are Healthy-years Equivalents an Improvement over Quality-adjusted Life Years?

The construct of the healthy-years equivalent (HYE) has been proposed as an alternative to the quality-adjusted life year (QALY) on the grounds that it avoids certain restrictive assumptions about preferences and also incorporates attitudes toward risk. The authors review the construct of the QALY, including both the commonly used risk-neutral formulation and the more general formulation that permits risk aversion (or risk preference) with respect to remaining life years. They show that the HYE adds flexibility to the risk-neutral form of the QALY by permitting the rate of tradeoff between life years and quality of life to depend on the life span, albeit at the cost of eliciting numerous additional time-tradeoff assessments. However, the claim that the HYE incorporates attitudes toward risk is incorrect, and the proposed two-stage procedure to measure HYEs is neither necessary nor sufficient to in corporate attitudes toward risk. In fact, the HYE assumes risk neutrality with respect to healthy years of life and, therefore, is less suitable for decisions under uncertainty than is the general (risk-averse) form of the QALY. Key words: quality-adjusted life years; healthy- years equivalents; economic evaluation; medical decision making; individual preferences; time-tradeoff; standard gamble; utility theory.