1. Dimensionality and psychometric analysis of DLQI in a Brazilian population
- Author
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Marilia F. S. Jorge, Ticiane D. Sousa, Camila F. Pollo, Bianca S. R. Paiva, Mayra Ianhez, Juliana C. Boza, Silmara Meneguin, Juliano V. Schmitt, Daniel Holthausen Nunes, Joel C. Lastoria, and Hélio A. Miot
- Subjects
Dermatology ,Psychometrics ,Questionnaires ,Health-related quality of life ,Validity ,Factor analysis ,Computer applications to medicine. Medical informatics ,R858-859.7 - Abstract
Abstract Background The Dermatology Life Quality Index (DLQI) is the most commonly used instrument for clinical evaluation of the impact on health-related quality of life (HRQOL) in dermatological research protocols. The DLQI’s classical psychometric properties have been considered adequate in validation studies from several countries. However, the structure of the DLQI is a matter of discussion, especially concerning the dimensionality and informative properties of its questions according to the item response theory (IRT). Methods Pooled data from studies in Brazil that utilized the DLQI to assess HRQOL in 14 dermatoses were reanalyzed. Classical psychometrical analysis, dimensionality assessment through parallel analysis and IRT (Samejima’s ordinal model) analysis were performed. Results The sample consisted of 1286 patients with a mean age of 47 years (SD = 16), and the proportion of women was 59% (765). The DLQI scores ranged from 0 to 29, with a median (p25–p75) of 5 (2–11). All items indicated significant correlations with the total DLQI score (rho > 0.54). The Cronbach’s alpha result was 0.90 (CI 95% 0.89–0.91). Parallel analysis indicated a unidimensional factor structure. According to IRT analysis, items q6 (sports) and q7 (work/study) exhibited insufficient fit to the model (p
- Published
- 2020
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