Chinese version of the Treatment of Autoimmune Bullous Disease Quality of Life questionnaire: Reliability and validity

Background: Treatments for autoimmune blistering disease carry significant risks of medical complications and can affect the patient's quality of life. Recently, the Treatment of Autoimmune Bullous Disease Quality of Life questionnaire was developed in Australia. Objective: The objective of this study was to evaluate the reliability and validity of the Chinese version of the Treatment of Autoimmune Bullous Disease Quality of Life questionnaire in Chinese patients with autoimmune blistering diseases. Methods: The Chinese version of the Treatment of Autoimmune Bullous Disease Quality of Life questionnaire was produced by forward-backward translation and cross-cultural adaptation of the original English version. Autoimmune blistering disease patients recruited in the study self-administered the Chinese Treatment of Autoimmune Bullous Disease Quality of Life questionnaire, the Dermatology Life Quality Index and the 36-item Short-Form Health Survey. Reliability of the Chinese Treatment of Autoimmune Bullous Disease Quality of Life was evaluated using internal consistency and test-retest (days 0 and 7) methods. Validity was analyzed by face, content, construct, convergent and discriminant validity measures. Results: A total of 86 autoimmune blistering disease patients were recruited for the study. Cronbach's alpha coefficient was 0.883 and the intraclass correlation coefficient was 0.871. Face and content validities were satisfactory. Convergent validity testing revealed correlation coefficients of 0.664 for the Treatment of Autoimmune Bullous Disease Quality of Life and Dermatology Life Quality Index and -0.577 for the Treatment of Autoimmune Bullous Disease Quality of Life and 36-item Short-Form Health Survey. With respect to discriminant validity, no significant differences were observed in the Treatment of Autoimmune Bullous Disease Quality of Life scores of men and women (t = 0.251, P = 0.802), inpatients and outpatients (t = 0.447, P = 0.656), patients on steroids and steroid-sparing medications (t = 0.672, P = 0.503) and patients with different autoimmune blistering disease subtypes (F = 0.030, P = 0.971). Limitations: Illiterate patients were excluded from the study. The patients were from a single hospital and most of their conditions were in a relatively stable status. Conclusion: The Chinese version of the Treatment of Autoimmune Bullous Disease Quality of Life questionnaire is a reliable and valid instrument to measure treatment burden and to serve as an end point in clinical trials in Chinese autoimmune blistering disease patients.