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

ObjectivesThe 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.MethodsWe 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.ResultsThe 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."ConclusionsThis 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.