Background: Most currently available dermatologic quality-of-life measures were originally created in English, and must be translated and adapted for use in other cultures. Our purpose was to translate and adapt culturally into Spanish a skin-related quality-of-life measure, Skindex-29, and to begin preliminary assessments of its reliability and validity.
Methods: Transcultural adaptation and cross-sectional questionnaire studies were performed. One hundred and fourteen adult persons (patients and healthy people) responded to the Spanish version of Skindex-29. Evaluations of the semantic equivalence of back-translated items, reliability, construct validity, and content validity of the Spanish version were the main outcome measures. Comparison between Spanish and American responses was also performed.
Results: Six problematic items required a second translation and back-translation to achieve satisfactory agreement with the original instrument. The final Spanish version of Skindex-29 was internally reliable (range of Cronbach alpha for the scales, 0.70-0.87). The instrument demonstrated both construct and content validity. As hypothesized, scores for dermatologic patients were higher than those for healthy persons (mean global scores 21 vs. 5, P < 0.01) and scores for patients with inflammatory diseases were higher than those for persons with isolated skin lesions (mean global scores 32 vs. 11, P < 0.01), indicating a poorer quality of life. In addition, most patients' responses to an open-ended question about their skin disease were addressed by items in the instrument. Skindex scale scores of American and Spanish respondents were similar.
Conclusions: We have developed a semantically equivalent translation of Skindex-29 into Spanish. Our preliminary evaluation of its measurement properties suggests that it is a reliable and valid measure of the effects of skin disease on the quality of life in Spanish patients.