Weighting and valuing quality-adjusted life-years using stated preference methods: preliminary results from the Social Value of a QALY Project.

OBJECTIVES: To identify characteristics of beneficiaries of health care over which relative weights should be derived and to estimate relative weights to be attached to health gains according to characteristics of recipients of these gains (relativities study); and to assess the feasibility of estimating a willingness-to-pay (WTP)-based value of a quality-adjusted life-year (QALY) (valuation study). DESIGN: Two interview-based surveys were administered - one (for the relativities study) to a nationally representative sample of the population in England and the other (for the valuation study) to a smaller convenience sample. SETTING: The two surveys were administered by the National Centre for Social Research (NatCen) in respondents' homes. PARTICIPANTS: 587 members of the public were interviewed for the relativities study and 409 for the valuation study. METHODS: In the relativities study, in-depth qualitative work and considerations of policy relevance resulted in the identification of age and severity of illness as relevant characteristics. Scenarios reflecting these, along with additional components reflecting gains in QALYs, were presented to respondents in a series of pairwise choices using two types of question: discrete choice and matching. These questions were part of a longer questionnaire (including attitudinal and sociodemographic questions), which was administered face to face using a computer-assisted personal interview. In the valuation study, respondents were asked about their WTP to avoid/prevent different durations of headache or stomach illness and to value these states on a scale (death = 0; full health = 1) using standard gamble (SG) questions. RESULTS: Discrete choice results showed that age and severity variables did not have a strong impact on respondents' choices over and above the health (QALY) gains presented. In contrast, matching showed age and severity impacts to be strong: depending on method of aggregation, gains to some groups were weighted three to four times more highly than gains to others. Results from the WTP and SG questions were combined in different ways to arrive at values of a QALY. These vary from values which are in the vicinity of the current National Institute for Health and Clinical Excellence (NICE) threshold to extremely high values. CONCLUSIONS: With respect to relative weights, more research is required to explore methodological differences with respect to age and severity weighting. On valuation, there are particular issues concerning the extent to which 'noise' and 'error' in people's responses might generate extreme and unreliable figures. Methods of aggregation and measures of central tendency were issues in both weighting and valuation procedures and require further exploration.

Equity considerations in health care: the relevance of claims.

The general issues of equity and efficiency are central to the analysis of resource allocation problems in health care. We examine them using axiomatic bargaining theory. We study different solutions that have been proposed and relate them to previous literature on health care allocation. In particular, we focus on the solutions based on axiomatic bargaining with claims, and show that they are appealing as distributive criteria in health policy. Finally, we present the results of a survey that tries to elicit moral intuitions of people about resource allocation problems and their different solutions.

Improving value measurement in cost-effectiveness analysis.

OBJECTIVE: Before cost-effectiveness analysis (CEA) can fulfill its promise as a tool to guide health care allocation decisions, the method of incorporating societal values into CEA may need to be improved. DESIGN: The study design was a declarative exposition of potential fallacies in the theoretical underpinnings of CEA. Two values held by many people-preferences for giving priority to severely ill patients and preferences to avoid discrimination against people who have limited treatment potential because of disability or chronic illness-that are not currently incorporated into CEA are discussed. CONCLUSIONS: Traditional CEA, through the measurement of quality-adjusted life years (QALYs), is constrained because of a "QALY trap." If, for example, saving the life of a person with paraplegia is equally valuable as saving the life of a person without paraplegia, then current QALY methods force us to conclude that curing paraplegia brings no benefit. Basing cost-effectiveness measurement on societal values rather than QALYs may allow us to better capture public rationing preferences, thereby escaping the QALY trap. CEA can accommodate a wider range of such societal values about fairness in its measurements by amending its methodology.

Health state after treatment: a reason for discrimination?

In this paper the issue of discrimination between patients based on the health improvement that each can achieve is addressed. Previous research in this area by Nord has shown that, in this context, society's preferences may be quite opposite to the principle of health maximization present in cost utility analysis. Using a different experimental design from that used by Nord, some results are achieved which suggest that social preferences may be somewhere in between two opposite extremes, which are that discrimination based on the degree of health improvement is never acceptable and that discrimination based on the degree of health improvement is always acceptable.

Life-saving treatments and disabilities. Are all QALYs created equal?

OBJECTIVES: Decision-makers and the general public are often reluctant to adopt policy recommendations based exclusively upon cost-utility analyses. One possible reason explored here is that patients' previous health state before experiencing the onset of an acute life-threatening illness may influence the value of saving those patients' lives. METHODS: We surveyed members of the general public to see the relative importance of saving patients' lives when some patients could be returned to perfect health and others would live the remainder of their years with paraplegia. Among this latter group, some were described as having pre-existing paraplegia. Others were described as having as having the onset of paraplegia. The relative importance of saving each of these lives was measured using the person trade-off method. RESULTS: Six hundred five subjects completed questionnaires, and 250 met pre-established consistency criteria and were included in the final analysis. Overall, subjects placed equal importance on saving the lives of people with pre-existing paraplegia versus those who could be returned to perfect health because they did not have pre-existing paraplegia. In contrast, respondents gave lower priority to patients who would experience the onset of paraplegia after having their lives saved, especially if their paraplegia was avoidable with an alternative treatment. CONCLUSION: People do not think that all quality-adjusted life-years are created equal. Instead, the value that people place on treatment programs depends on patients' state of health before developing life-threatening illnesses, and on whether alternative treatments are available that provide better health outcomes for the patients. These results may explain, in part, public discomfort over basing health care priorities on cost-utility analysis.

More evidence of the plateau effect: a social perspective.

The purpose of this study was to test the existence of the plateau effect at the social level. The authors tried to confirm the preliminary conclusion that people may not be willing to trade off any longevity to improve the health state of a large number of people if the health states are mild enough. They tested this assumption using the person-tradeoff technique. They also used a parametric approach and a nonparametric approach to study the relationship between individual and social values. Results show the existence of the plateau effect in the context of resource allocation. Furthermore, with the nonparametric approach, a plateau effect in the middle part of the scale was also observed, suggesting that social preference may not be directly predicted from individual utilities. The authors caution against the possible framing effects that may be present in these kinds of questions.

Is the person trade-off a valid method for allocating health care resources?

The Person Trade-Off (PTO) is a methodology aimed at measuring the social value of health states. It is claimed that other methods measure individual utility and are less appropriate for taking resource allocation decisions. However, few studies have been conducted to test the apparent superiority of the method for this particular kind of decision. We present a pilot study to this end. The study is based on the results of interviewing 30 undergraduate students in economics. We compare two well known techniques, the Standard Gamble and the Visual Analogue Scale, with the PTO. The criterion against which the performance of the methods is assessed is the directly obtained preference about how to establish priorities among hypothetical patients waiting for treatment. Apparently the PTO performed better than the others. We also compare three different frames for the PTO. One of them seems to predict people's preferences.