A hybrid modelling approach for eliciting health state preferences: the Portuguese EQ-5D-5L value set
The EQ-5D is a generic preference-based quality of life measure considered useful for supporting clinical and policy decisions by providing utility values that can easily be converted into quality-adjusted life years to be integrated in cost-utility economic evaluations. Although the three-level classification system of the EuroQol questionnaire (EQ-5D-3L) is still the most popular preference-based instrument used worldwide, several studies reported a ceiling effect on this version, especially in healthy and/or young individuals. In 2009, the EuroQol Group introduced a five-level EQ-5D, which expands the descriptive system from three to five levels within the same five dimensions. For this version to be used in health economic evaluation, societal values need to be assigned to the 3125 health states generated by this instrument.
The aims of this study were to elicit the EQ-5D-5L health state preferences from the general Portuguese population and to derive the Portuguese value set for the EQ-5D-5L.
A representative sample of the Portuguese general population aged above 18 years was stratified by age and gender (n = 1451). Between October 2015 and July 2016, 28 interviewers carried out a series of 1-h-long computer-assisted personal interviews following the EuroQol Valuation Technology protocol. Each interview included the valuation of ten health states using the composite time trade-off (cTTO) and seven pairs of discrete choice experiments (DCEs). A standardized tool for quality control was used to assess the quality of the data as well as direct supervision and cross-examination of 10% of the global sample size. Data from both cTTO and DCE valuation tasks were modelled using a censored heteroskedastic hybrid model.
Interviewers complied with the quality control protocol in providing high-quality valuation data. The hybrid econometric model had consistent and significant parameters. The derived societal values for the Portuguese population ranged from − 0.603 to 1.
This study provided the Portuguese value set for the EQ-5D-5L on the basis of a hybrid econometric model using cTTO and DCE data. These results represent the preferences of the Portuguese population and are recommended to inform health decision-making in Portugal.
KeywordsEQ-5D-5L Preferences Portuguese value set Composite time trade-off Discrete choice experiment Quality of life
This research was part of an EuroQoL international project aimed at obtaining country-specific EQ-5D-5L value sets. The authors are grateful to the EuroQol Group (Elly Stolk and Bernhard Slaap) for the opportunity to implement this study in Portugal and to the technical team (Kristina Ludwig and Arnd Jan Prause) for their continuous advice and support. Views expressed in the paper are those of the authors alone. The authors are thankful for support from the Centre for Health Studies & Research-University of Coimbra (CEISUC) [FCT-Foundation for Science and Technology Grant Number UID/MULTI/4066/2019] and from the Research Centre for Spatial and Organizational Dynamics-University of the Algarve (CIEO) [FCT Grant Number UID/SOC/04020/2019].
This study was funded by a grant from the EuroQol Research Foundation.
Compliance with ethical standards
Conflict of interest
One author discloses that he is a member of the EuroQol Group, an organization focused on the development of instruments that describe and value health outside the for-profit model. The views expressed by the authors in the publication do not necessarily reflect the views of the EuroQol Group. The authors declare that they have no conflicts of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. This study was reviewed and approved by the (Portuguese) National Data Protection Commission (Ref. 1737/2015) to elicit the preferences of the Portuguese general population, preserving the anonymity and confidentiality of the participants.
Informed consent was obtained from all individual participants included in the study. Participants were informed about their freedom for refusal.
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