Valuing Health

Health care can improve people’s quality of life, and it can help them live longer. The qualityadjusted-life-years (QALYs) approach has been developed to express these twin components of benefit (quality and quantity of life) in a single number. It expresses different health states on a scale between 0 for death and 1 for full health and then multiplies these values by how long the states last. One QALY is equivalent to 1 year of life in full health. By comparing how many QALYs different interventions are expected to generate with how much those interventions are expected to cost, it is possible to show the cost-effectiveness of different uses of resources. In the United Kingdom, the National Institute for Health and Clinical Excellence (NICE) recommends that ‘‘the value of changes in patients’ health related quality of life should be based on public preferences using a choice-based method . [and] the EQ-5D is the preferred measure of HRQL in adults. ’’ The EQ-5D defines health in terms of 1 of 3 levels of severity (broadly, no problems, some problems, and extreme problems) associated with each of 5 dimensions (mobility, self-care, usual activities, pain/discomfort, anxiety/depression). Each of the 243 (3) health states are represented by a 5-digit code, ranging from 11111 for full health to 33333 for extreme problems on all 5 dimensions. Values for these states have been elicited by asking members of the public for their time tradeoff (TTO) preferences, that is, to state how many years of life in 11111 they consider to be equivalent to a longer period of time in one of the remaining 242 ‘‘poor’’ health states. There is a long tradition of asking for people’s preferences over future, hypothetical prospects. 5,6 It is also not without its problems, most notably the fact that circumstances often affect individuals quite differently from how they imagine them. If, say, we overestimate the impact on our lives of mobility relative to anxiety/depression, then all else equal, agencies such as NICE will end up allocating relatively more priority to health states that affect mobility—and relatively less to anxiety/ depression—than would be the case if priorities were set according to the actual impact those states had on our lives. One way of assessing how health states affect us is to consider their association with subjective well-being (SWB). In general, SWB can be measured by global evaluations of life overall (e.g., life satisfaction) or by experiences of daily affect (e.g., feelings about yesterday). There is increasing interest in the use of SWB for policy purposes, as highlighted by the recent influential Sarkozy commissionand the widespread assessment of SWB in the United Kingdom. There have, however, been few attempts to relate SWB and health status, although Graham and others did show the association between the EQ5D and Cantrill’s ‘‘ladder of life,’’ which asks respondents to rate their life with best and worst possible life as endpoints. These data suggest that mobility does indeed have less impact than anxiety/depression. There are no studies showing how the EQ5D affects life satisfaction, which is a much more widely used evaluative measure of SWB, and there are no studies showing how the EQ5D affects more direct measures of experience, such as ‘‘day affect’’ (mood during the day). Critically, there have also been no previous attempts to show how health state values based on the general public’s willingness to give up life-years compare to values estimated Received 10 August 2011 from London School of Economics, London, UK (PD), and University of Oxford, Merton College, Oxford, UK (RM). Revision accepted for publication 6 December 2011.