Background: Measuring the health-related quality of life is an essential estimation in cost-utility studies. In this research, we provide new evidence about comparing utility scores - in the field of substance dependence. Although the main objective is to compare the EQ-5D-5L and SF-6D with paired gamble, evidence about the SF-6D with standard gamble is also provided.
Methods: Ninety-four patients with substance dependence were recruited; the SF-6D and the EQ-5D-5L were administered at the beginning of treatment and 6 months thereafter. Differences in treatment effect were estimated by comparing utility gains. All analyses were reproduced for two subgroups of severity.
Results: Both the baseline scores and the treatment effect are sensitive to the instrument used. For severe states, the SF-6D with paired gamble (SF-6D with standard gamble) estimates the lowest (highest) utility. With regard to the impact of treatment, the EQ-5D-5L and SF-6D with paired gamble estimate strongly similar effects for severe states (and both estimate greater effects than does the SF-6D with standard gamble).
Conclusions: These findings have implications for cost-utility analyses. The incremental cost-utility ratio of treatments intended for severe states is barely sensitive to the choice of EQ-5D-5L or SF-6D with paired gamble.
Keywords: EQ-5D-5L; SF-6D; paired gamble; quality of life; standard gamble; substance dependence.