Healthy year equivalents versus quality-adjusted life years: the debate continues.
The quality-adjusted life year makes a number of restrictive assumptions about the nature of one's preference over health. The healthy year equivalent was originally proposed over 10 years ago as a major theoretic advance on the quality-adjusted life year. This article reviews the theoretic, empiric and normative bases for the healthy year equivalent and quality-adjusted life year approaches to valuing health profiles that vary over time. Although critics have argued that the two-stage procedure proposed by the developers of healthy year equivalent is theoretically equivalent to a generalized time trade-off question, the notion of directly valuing a series of health states in a health profile has been an important contribution to the literature. Since then, new quality-adjusted life year approaches have been developed to combine health states that vary over time. However, these approaches have yet to be tested empirically. The empiric evidence comparing quality-adjusted life years with healthy year equivalents is equivocal, and the size and direction of difference is context specific. In some studies, no differences have been found. At the same time, where differences are observed, it is difficult to interpret the healthy year equivalent values as the gold standard since there is evidence of cognitive confusion in the answers being given to the valuations of complex health profiles. Based on the evidence to date, it is not clear that healthy year equivalents provide a better measure of preferences than quality-adjusted life years.
Towers
Isabel
I
University of Sheffield, Health Economics & Decision Science, School of Health & Related Research, Sheffield, UK. cmp98imt@shef.ac.uk
Spencer
Anne
A
Brazier
John
J