The development and validation of the Treatment of Autoimmune Bullous Disease Quality of Life questionnaire, a tool to measure the quality of life impacts of treatments used in patients with autoimmune blistering disease

Summary Background Treatments for autoimmune blistering diseases have significant risk of medical complications and quality of life impacts during treatment, and it is difficult to differentiate these impacts from disease burden or the effects of treatment. Objectives To develop a quality of life instrument specific to the effects of treatments used in patients with autoimmune bullous disease (AIBD). Methods A comprehensive item generation process was used to build a 45‐item pilot Autoimmune Bullous Disease Quality of Life (ABQOL) questionnaire, distributed to 70 patients with AIBD. Experts in bullous disease refined the pilot ABQOL, selecting only those questions pertaining to the treatment effects. This pilot Treatment of Autoimmune Bullous Disease Quality of Life (TABQOL) questionnaire was administered to 70 patients, before factor analysis was performed to yield the final questionnaire of 17 questions. Validity and reliability were evaluated across a range of indices. Results Face and content validity were established through a comprehensive patient interview process, expert review and summaries of treatments used. The questionnaire was found to have appropriate correlation with the Dermatology Life Quality Index (r = 0·64) and the level of treatments used (P