Measurement properties of the EQ-5D-5L compared to the EQ-5D-3L in psoriasis patients
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Abstract
The purpose of this study is to assess the measurement properties of EQ-5D-5L compared to EQ-5D-3L in psoriasis patients.
Methods
A cross-sectional survey was carried out at an academic dermatology clinic in Hungary. Psoriasis patients completed the EQ-5D-3L, EQ-5D-5L and Dermatology Life Quality Index (DLQI) questionnaires, and Psoriasis Area and Severity Index (PASI) was assessed. The UK value sets were used to calculate the 3L and 5L index scores. We tested the feasibility, ceiling effect, redistribution properties, the level of inconsistency and informativity (Shannon and Shannon Evenness indices). Spearman’s rank-order correlations were performed between EQ-5D, EQ VAS, DLQI and PASI scores. Known-groups validity was evaluated by comparing age groups, clinical subtypes and treatment groups.
Results
Mean age of the 238 patients was 47 years, and 36.6% of them received biological therapy. Mean EQ-5D index score was 0.77 (SD: 0.26) with the 3L and 0.84 (SD: 0.19) with the 5L. The overall ceiling effect decreased from 37.1 (3L) to 32.9% (5L). Shannon index improved significantly for most dimensions, but Shannon Evenness index improved only in three dimensions. Compared to the 3L, the 5L version confirmed a better convergent validity with PASI, but not with the DLQI. Known-groups validity was equally demonstrated both for the 5L and 3L.
Conclusions
The EQ-5D-5L seems to improve measurement properties by reducing ceiling effects, strengthening correlations with PASI and improving informativity. Follow-up studies are needed to test responsiveness and reliability in psoriasis.
Keywords
EQ-5D-3L EQ-5D-5L Psoriasis Health-related quality of life Measurement properties PsychometricsNotes
Acknowledgements
Authors are grateful to Elly Stolk (EuroQol Group, Scientific Team Leader) and Miklós Sárdy (Semmelweis University, Department of Dermatology, Venereology and Dermatooncology) for their valuable comments on the manuscript.
Funding
Márta Péntek’s work in this study was supported by an independent research grant from her employer Corvinus University of Budapest (‘Kutatási Kiválóság Díj 2016’—Research Excellence Award 2016).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
Ethical standard
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. The study protocol was approved by the Semmelweis University Regional and Institutional Committee of Science and Research Ethics (Reference No. 58./2015).
Informed consent
Informed consent was obtained from all participants included in the study.
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