Effect of including (versus excluding) fates worse than death on utility measurement.

Abstract

Most studies typically measure health preferences excluding health states perceived as worse than death. The objective of this study is to test the impact of including (versus excluding) health states perceived to be worse than death on utility measurement using standard gamble (SG) and visual analogue scale (VAS) methods. By means of a cross-sectional descriptive study design, women were asked to rate the utility of three hypothetical breast cancer health states: cure, treatment, and recurrence (n=119). Preference weights were estimated, allowing for negative utilities with death (perfect health) scaled at zero (1.0). Unpaired t-test analysis showed significantly greater change in SG and VAS weights for individuals perceiving cancer recurrence as worse than death than those perceiving death as least desirable state. Excluding negative utilities from the study resulted in significantly smaller changes in utility. Study results show that preference elicitation methods can be successfully adapted to acquire negative utilities. Changes in utility were greater when negative preferences were permitted. Addressing negative preference scores could significantly affect quality adjusted life year estimates in economic analyses.