The Use of Preference Techniques to Value the Health Gains from Treatment: Kaposi's Sarcoma

Aims: To investigate preference techniques to value potential health gains from treatments of Kaposi's sarcoma (KS). Patients and Methods Face-to-face interview of a sample of men with a history of HIV/AIDS (N=15) or HIV/AIDS and KS (N=17). The main outcome measure was Quality of life (QoL) associated with various KS disease states expressed on a scale from 0 (death) to 1 (perfect health) obtained though time trade off (TTO) and rating scale techniques. Results: For cutaneous lesions only, the mean TTO utility values was 0.27. In other words the men were willing to trade a life expectancy of 5 years for a shorter period (1.4 years) in perfect health. More severe KS health states were rated lower (0.07 to 0.09). The mean rating scale value for cutaneous lesions only was 0.11 and ranged from -0.10 to -0.04 for the more severe conditions and were systematically lower than the TTO (p=0.014). A large overall potential gain in quality of life from treatment (partial response minus stable disease) was found for each condition for both the TTO (0.31 to 0.55) and the rating scale (0.38 to 0.44). Conclusions: Respondents associate KS health states with extremely poor QoL and indicate that large gains are possible through modest treatment effects. While TTO returns higher values than the rating scale, potential gain from treatments were similar. The techniques appear suitable for application to QoL and economic evaluation of treatments of KS.