The Japanese version of Skindex-16: a brief quality-of-life measure for patients with skin diseases.

A practical quality-of-life measure applicable to patients with skin diseases is necessary. Recently developed dermatological quality-of-life measures must be translated and adapted for use in cultures other than the ones in which they were created. In this study, we translated and adapted culturally into Japanese a skin-disease-specific, brief quality-of-life measure, Skindex-16, and studied its reliability and validity. Forward-and back-translations of Skindex-16 were carried out. Six doubtful items as well as the term "skin condition" required a second forward- and back-translation to reach satisfactory agreement with the original instrument. Cross-cultural adaptation and cross-sectional questionnaire studies were then performed to evaluate the reliability and validity of the instrument. One hundred patients and 30 healthy adults responded to the Japanese version. The internal-consistency reliability of the final Japanese version of Skindex-16 was high (range of Cronbach's alpha for each scale, symptoms, emotions, and functioning, was 0.83-0.92). The Japanese version showed construct and content validity. As hypothesized, scores for dermatological patients were higher than those for healthy persons (mean global scores 36 +/- 23 vs 1 +/- 2, p < 0.001) and scores for patients with inflammatory diseases were higher than those for patients with isolated skin lesions (mean global scores 48 +/- 21 vs 22 +/- 17, p < 0.001), indicating a poorer quality of life. Most patients' responses to an open-ended question about their skin disease were similar to those of the American responders and were addressed according to the items. In conclusion, we have developed a semantically equivalent translation of Skindex-16 into Japanese. It is a reliable and valid measure of the effects of skin disease on the quality of life in Japanese patients.