Development of Japanese versions of the Autoimmune Bullous Disease Quality of Life and Treatment of Autoimmune Bullous Disease Quality of Life questionnaires.

Patients with autoimmune bullous disease have their quality of life (QOL) affected by both the disease and its treatment burden. While QOL assessment is clinically important, it is often hindered by limited time in clinical practice, highlighting the need for accurate and efficient QOL evaluation tools. However, no validated QOL questionnaires are currently available in Japan. This study evaluated the validity and reliability of the Japanese versions of the Autoimmune Bullous Disease Quality of Life (ABQOL) and Treatment of Autoimmune Bullous Disease Quality of Life (TABQOL) questionnaires, as well as their practical application in clinical settings. The original questionnaires were forward and back-translated into Japanese by certified translators according to established guidelines, then their validity and reliability were evaluated using data from 147 patients with autoimmune bullous diseases. Validity was evaluated via confirmatory and exploratory factor analyses, cross-cultural validation, hypothesis testing, and convergent validity. Reliability was evaluated via test-retest and internal consistency. Although confirmatory factor analysis showed a weak fit and factor structures slightly differed from the original versions, internal consistency was cross-culturally valid. Also, the Japanese version cohort showed lower mean scores and better QOL outcomes compared with other language versions for similar cohorts. Hypothesis testing revealed a significant positive correlation between ABQOL scores and subjective disease severity; TABQOL scores were significantly correlated with steroid dosage. The mucosal subscale of the ABQOL showed a significant difference based on mucosal lesion status. Bland-Altman plots confirmed approximate agreement between the two sets of measurements: Cronbach's alpha coefficients were 0.872 for ABQOL and 0.903 for TABQOL, verifying reliability. Finally, an expert panel reviewed and agreed on the target population, timing, methods for using the scales, and considerations for scale evaluation. The Japanese versions of the ABQOL and TABQOL are expected to be implemented in clinical practice as reliable and validated tools in Japan.