Developing an Australian Value Set for the Recovering Quality of Life-Utility Index (ReQoL-UI) instrument using Discrete Choice Experiment with Duration

Value Health. 2025 Jan 17:S1098-3015(25)00013-0. doi: 10.1016/j.jval.2024.12.008. Online ahead of print.

Abstract

Objectives: The Recovering Quality of Life-Utility Index (ReQoL-UI) instrument was designed to measure the quality of life outcomes for people over 16 years of age with mental health problems. We aim to elicit societal preferences for the ReQoL-UI health states to facilitate better decision-making in Australia.

Methods: A discrete choice experiment (DCE) with duration was embedded in a self-complete online survey and administered to a representative sample (n=1019) of the Australian adult population aged 18 years and more, stratified for age, sex and geographic location. A partial subset design DCE was used with 3 fixed attributes and 5 varying attributes containing 240 choice tasks that were blocked into 20 blocks, so that each respondent was assigned a block of 12 choice tasks. The value set was modelled using the conditional logit model with utility decrements directly anchored on the 0 to 1 dead-full health scale. Preference heterogeneity was tested using the mixed logit model.

Results: The final value set reflects the monotonic nature of the ReQoL-UI descriptive systems where the best health state defined by the descriptive system has a value of 1 and the worst state has a value of -0.585. The most important dimension was physical health problems while the least important attribute was self-perception. Sensitivity analysis and analysis of preference heterogeneity show the stability of the value set.

Conclusion: The value set which reflects the preferences of the Australian population facilitates the calculation of an index for quality-adjusted life years in mental health interventions cost-utility analyses.

Keywords: Australia; QALYs; Recovering Quality of life; mental health; value set.