Psychometrican analysis and dimensional structure of the Brazilian version of melasma quality of life scale (MELASQoL BP)
Background Although asymptomatic, melasma inflicts significant impact on quality of life. MELASQoL is the main instrument used to assess quality of life associated with melasma, it has been validated in several languages, but its latent dimensional structure and psychometric properties haven't been fully explored. Objectives To evaluate psychometric characteristics, information and dimensional structure of the Brazilian version of MELASQoL. Methods Survey with patients with facial melasma through socio demographic questionnaire, DLQI BRA, MASI and MELASQoL BP, exploratory and confirmatory factor analysis, internal consistency of MELASQoL and latent dimensions (Cronbach's alpha) The informativeness of the model and items were investigated by the Rasch model (ordinal data) Results We evaluated 154 patients, 134 (87% were female, mean age SD) of 39 8) years, the onset of melasma at 27 8) years, median (p25 p75) of MASI scores DLQI and MELASQoL 8 (5 15) 2 (1 6) and 30 (17 44) The correlation (rho) of MELASQoL with DLQI and MASI were: 0.70 and 0.36. Exploratory factor analysis identified two latent dimensions: Q1 Q3 and Q4 Q10, which had significantly more adjusted factor structure than the one dimensional model: Kh2 gl 2.03, CFI 0.95, AGFI 0.94, RMSEA 0.08. Cronbach's coefficient for the one dimensional model and the factors were: 0.95, 0.92 and 0.93. Rasch analysis demonstrated that the use of seven alternatives per item resulted in no increase in the model informativeness. Conclusions MELASQoL BP showed good psychometric performance and a latent structure of two dimensions. We also identified an oversizing of item alternatives to characterize the aggregate information to each dimension.
Anais brasileiros de dermatologia