Development and construct validation of the angioedema quality of life questionnaire

Background Recurrent angioedema is a frequent clinical problem characterized by unpredictably and rapidly occurring cutaneous and mucosal swellings. These swellings may be painful and/or disfiguring. Upper airway involvement can also lead to dyspnea and suffocation. Although the disease burden is high, there is currently no specific instrument to measure health-related quality of life (QoL) impairment. Objective To develop and validate the first symptom-specific tool to assess QoL impairment in recurrent angioedema patients, adhering to established methodological recommendations. Methods During the development phase, 29 questions (items) were generated. Subsequently, item reduction was performed by means of impact analysis and factor analysis as well as by checking for content and face validity. As a result, 17 items were selected and included in the final instrument, the Angioedema QoL Questionnaire (AE-QoL). AE-QoL was then tested for its validity, reliability, and influence factors. Results One hundred and ten angioedema patients took part in the validation of AE-QoL. AE-QoL was found to have a four-dimensional structure as well as a valid total score. All of its four domains (functioning, fatigue/mood, fears/shame, food) showed good levels of internal consistency with Cronbach's alpha > 0.8. Test–retesting revealed a good reliability of the instruments total score and domain scores. Gender as well as the patients' self-rated disease activity was found to be predictors of the AE-QoL total score. Conclusions Angioedema Quality of Life Questionnaire is the first angioedema-specific QoL questionnaire. It is a short, valid and reliable instrument that may serve as a valuable tool in future clinical studies and in routine patient care.