Healthy Years Equivalents

Concept

The underlying premise of cost utility/effectiveness analysis (CUA/CEA) is that for a given level of resources available, society or the decision maker wishes to maximize the total aggregate health benefits conferred by a proposed treatment. The principles underlying CUA/CEA are concerned with the simultaneous satisfaction of efficiency in both production (i.e., making sure that each level of outcome is produced with the minimum amount of resources) and product mix (i.e., making sure that the allocation of available resources between different “products” is optimal). In this way, CUA/CEA is consistent with the principles of welfare economics theory and a welfarist approach to economics. But to achieve the goal of maximizing health-related well-being (i.e., utility associated with health benefits) from available resources, the methods used to measure health-related well-being must be consistent with the theories on which the welfarist approach and principles of CUA are based. Under the welfarist approach, an individual's preferences are embodied in that individual's utility function. Thus, for a measure of outcome to be consistent with the welfarist approach, and hence CUA/CEA principles, it must be consistent with a theory of utility. Health (i.e., an expected profile of health over lifetime) is one argument in an individual's utility function.

From the perspective of the economist qua economist, “pure utility” is sufficient for comparing alternatives on the basis of individuals' preferences. Hence, for a von Neumann-Morgenstern (vNM)-type individual, for example, a single standard gamble (SG) question can provide the utility score (i.e., number of utils) for any potential lifetime health profile. But the utils measure, and the notion of cost per util, may not be very meaningful to individuals and organizations making choices among programs associated with different expected health profiles. Abraham Mehrez and Amiram Gafni, who were the first to introduce the approach, explained that the HYE responds to the need to improve communication within and among researchers, managers, practitioners, and consumers in a way that is consistent with the concept of utility and hence represents individuals' preferences. The HYE is not a direct measure of utility. It is an attempt to reflect individuals' preferences concerning uncertain health profiles using one argument in their utility function (i.e., duration), holding health status constant (i.e., full health). The intuitive appeal of years in full health has been established by the QALY measure, which was designed to be thought of as an equivalent number of years in full health—a number of quality-adjusted life years (QALYs). A different name was chosen to distinguish the HYE, which is a utility-based concept, from the QALY. Furthermore, it has been argued that length of life in full health—that is, healthy-years equivalent—represents a much simpler concept to explain to decision makers than the variable quality of life health status annuity, which the QALY represents.

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