Reliability and validity of the Chinese version of the vitiligo specific quality of life instrument (VitiQoL)

Background: Vitiligo is an acquired, idiopathic skin disorder that can significantly affect the health-related quality of life (QoL). The vitiligo-specific QoL instrument (VitiQoL), recently developed by an American group, was found to be a reliable patient-reported outcome measure in both Brazilian and Iranian patients. Methods: The VitiQoL was initially cross-culturally adapted to Chinese through forward-backward translation. The Chinese version of the VitiQoL was then distributed to 182 vitiligo patients together with the dermatology life quality index (DLQI) and Skindex-16 questionnaire. Then, the reliability and validity of the Chinese version of the VitiQoL was assessed by statistical analysis. Results: The Chinese version of the VitiQoL showed high internal consistency (Cronbach alpha = 0.958) and test-retest reliability (intraclass correlation coefficient = 0.887). Convergent validity testing showed that the correlation coefficient for the Chinese VitiQoL and DLQI was 0.70 (P < 0.01), the Chinese VitiQoL and Skindex-16 each was 0.84 (P < 0.01), and for the Chinese VitiQoL (questions 1-15 and 16) was 0.62 (P < 0.01). Confirmatory factor analysis revealed two important factors within the VitiQoL: Participation limitation and stigma. Conclusion: The Chinese version of the VitiQoL questionnaire has sufficient reliability and validity to be used to evaluate Chinese vitiligo patients' QoL.