Estimating General-population Utilities Using One Binary-gamble Question per Respondent

Abstract

This study used a single binary-gamble question per health state per respondent to obtain societal preferences for the health states intermittent claudication and major amputation and compare those with Health Utilities Indices obtained from patients, to test the feasibility of this method, and to investigate whether the utility depends on the presentation of a vignette as generic vs disease-specific. A random sample of the general U.S. population (n = 1,003) was randomly divided into ten subgroups. In tel ephone interviews, subjects answered one binary-gamble question in a standard-gam ble format for each of two health states. The risks of death varied across subgroups but not between health states. Mean utility was estimated by the area above the pro portional distribution of responses indicating acceptance of the gamble. The method is based on the binary-choice method used in contingent-valuation studies of willing ness to pay. The health states were alternatively described by generic and disease- specific vignettes in two subsamples. The results suggest that the binary-gamble ques tion can be used to obtain societal preferences for health states, and that disease-specific descriptions yield lower utilities compared with generic descriptions of health states. Key words: peripheral arterial occlusive disease, intermittent claudica tion ; quality of life; standard gamble; utility assessment. (Med Decis Making 1998;18: 381-390)