Assessment of the psychometric properties of the EQ-5D-3L and EQ-5D-5L instruments in psoriasis
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The aim of this study was to assess the psychometric properties of the five-level (EQ-5D-5L) in comparison with the standard three-level (EQ-5D-3L) classification systems of the EQ-5D in a sample of psoriatic patients. Psoriatic subjects (n = 396) recruited from 16 private practicing centers from various areas of Greece self-completed the two EQ-5D versions and the Dermatology Life Quality Index, while information was also collected on socio-demographics, clinical characteristics and comorbidities. The EQ-5D-5L and EQ-5D-3L were evaluated in terms of agreement, feasibility, ceiling effects, redistribution properties, inconsistency, informativity, and convergent and known-groups validity. Missing values were negligible in both versions. The agreement between the EQ-5D-5L and the EQ-5D-3L was very high (ICC = 0.94), while the largest differences were identified for subjects with moderate health status. Ceiling effects decreased in the EQ-5D-5L system by 14.08% (p < 0.05), with “anxiety/depression” showing the highest relative reduction (−10.31%; p < 0.05). Overall inconsistency was rather low (1.7%) and respondents preferred to report milder problems in the EQ-5D-5L. Absolute informativity improved by 56.42% in the EQ-5D-5L, while relative informativity declined by 9.24%, with only “anxiety/depression” demonstrating a small increase (6.77%). Both instruments demonstrated good convergent and known-groups validity, with evidence of a slightly better convergent performance and discriminatory efficiency of the EQ-5D-5L. In conclusion, both instruments demonstrated consistency, valid redistribution and good construct validity. The EQ-5D-5L system may be preferable to the EQ-5D-3L in psoriatic patients, as it demonstrated a marginally better performance in terms of reduced ceiling effects, increased informativity, and improved convergent and known-groups validity efficiency, particularly in the domain of “anxiety/depression”.
KeywordsEQ-5D Health-related quality of life Psychometrics Validity Psoriasis Greece
To LEO Pharma for its collaboration with the University of Athens in providing the database to conduct the analysis.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in this study 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.
Informed consent was obtained from all individual participants included in the study.
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