Differences between hypothetical and experience-based value sets for EQ-5D used in Sweden: Implications for decision makers.

AIMS A number of value sets are available today for converting EQ-5D questionnaire responses to quality-adjusted life year-weights used in health economic evaluations. The aim of this study is to analyse the differences between the commonly used hypothetical UK value set and the newly introduced Swedish experience-based value set and to evaluate health economic implications of such differences on policy decisions. METHODS Differences between the two value sets were studied using two methods: a comparison of health states and improvements as well as an empirical comparison. In the comparison of health states and improvements, the valuations of all EQ-5D states and all pure improvements were compared. In the empirical study, a database of 23,925 individuals was used to identify patient groups that could be affected by the implementation of the Swedish experience-based value set. RESULTS The comparison of health states and possible improvements showed that only three health states were assigned a lower quality-adjusted life year-weight and most improvements were given smaller absolute values if the experience-based value set was used. The empirical comparison showed that severe conditions were assigned higher values when using the experience-based value set. CONCLUSIONS The Swedish experience-based value set seems to render a higher estimated level of health-related quality of life in virtually all health conditions compared to the hypothetical UK value set. In extension, health-related quality of life enhancing interventions are likely to be given higher priority in decision-making situations where hypothetical values are used to construct quality-adjusted life year-weights. In situations where experience-based quality-adjusted life year-weights are used, life-prolonging interventions would be prioritised.