Deriving a Korean SF-6Dv2 value set using a discrete choice experiment with duration

Objectives: This study aimed to derive a Korean value set for the SF-6Dv2.

Methods: Following an adapted international protocol, an online discrete choice experiment with duration (DCETTO) was conducted among 3,800 Korean adults representative of the general population. The experimental design included three components: choice sets from a Core Module, choice sets pairing commonly occurring health states (Common Module), and triplet choice sets with death options (Triplet Module). Preferences were analyzed using conditional and mixed logit models

Results: Model 9 (based on the Core Module) was selected as the preferred model for its superior logical consistency, including monotonicity of coefficients and avoidance of counterintuitive results. The pain dimension had the largest utility decrement at its worst level (−0.496), followed by physical functioning (−0.480), mental health (−0.391), social functioning (−0.329), vitality (−0.178), and role limitations (−0.138). The utility for the worst possible health state (556555) was estimated at −1.012, with 31.8% of all states valued as worse than dead. Significant preference heterogeneity was observed across dimensions, indicating substantial individual-level variation in health state valuations. While including death comparisons (Triplet Module) produced less negative worst-state utilities, it was not recommended as the primary value set due to its non-efficient experimental design and logical monotonicity issues necessitating greater level collapsing.

Conclusion: We derived the first Korean SF-6Dv2 value set. This enables quality-adjusted life year calculations from both SF-36v2 and SF-6Dv2 data, supporting economic evaluations in Korea.