Economic methods for measuring the quality of life associated with HIV infection

Background: Quality of life is measured as utilities for cost-effectiveness analyses. Objective: To test the adequacy of three common utility elicitat ion methods for individuals with Human Immunodeficiency Virus (HIV) disease . Measurements: HIV-positive participants (n = 75) rated three standardized health states (symptomatic HIV infection, minor AIDS defining illness, and major AIDS defining illness) with two utility elicitation methods (Standar d Gamble [SG], and Time Trade-off [TTO]) and one value method (Visual Analo g [VA]). Participants also rated their own health with one utility method ( Health Utilities Index [HUI]) and one conventional quality of life method ( Medical Outcomes Study-HIV Health Survey [MOS-HIV]). Results: For all state s, SG and TTO scores ranged from near 0.00 (equivalent to death) to 1.00 (b est possible quality of life). Mean scores for symptomatic HIV were similar with the SG (0.80) and TTO (0.81) but higher than with the VA (0.70). Simi lar results were observed for minor AIDS defining illnesses (0.65, 0.65, 0. 46 respectively) and major AIDS defining illnesses (0.42, 0.44, 0.25 respec tively). Discrepant SG and TTO scores were observed in many individuals and were not explained by demographic characteristics. As expected, HUI scores of an individual's own health were related to the disease state. Four of t en MOS-HIV subscales (overall health, physical functioning, role functionin g, and pain) were also related to disease state. HUI scores were correlated with the MOS-HIV score for overall health and for all MOS-HIV subscales ex cept health transition. Conclusions: Mean utility scores for HIV-related he alth states elicited by the Standard Gamble and Time Trade-off were similar but a large degree of individual variation persists. Economic methods prov ide imprecise estimates of the quality of life associated with HIV infectio n.