Developing a utility value set for the Gambling Quality of Life Scale-Brief (GQoLS-Brief) using a discrete choice experiment.

Abstract

Objectives: The Gambling Quality of Life Scale -brief (GQoLS-Brief) assesses the impact of gambling disorder (GD) on quality of life (QoL). Preference-based measures are essential for obtaining the quality adjustment weight (i.e. utility score) needed to calculate quality-adjusted life years (QALYs) in economic evaluations. We aimed to derive a value set for the GQoLS-Brief.

Methods: We employed a discrete choice experiment for preference elicitation. An online survey was administered (n = 928). Respondents completed 10 choice tasks, each presenting two GQoLS-Brief health states alongside life expectancy. Conditional logit regression, parameterized to fit the QALY framework, was used for data analysis. QALY weights for each health state defined by the GQoLS-Brief were calculated.

Results: The estimated coefficients from the conditional logit models aligned with expectations: utility increased with survival time and decreased with QoL impairment. Utility values for health states ranged from - 1.48 (worse than death) to 1.0. "Financial difficulties" exhibited the highest utility decrement, followed by "Sleep disturbance related to financial difficulties."

Conclusions: This reference set facilitates the calculation of QALYs for economic evaluations of GD interventions. The weight of subjective financial difficulties underscores the need for therapeutic interventions to target this aspect.