Development of the Shortness of Breath with Daily Activities questionnaire (SOBDA)

Based on qualitative research of patients with chronic obstructive pulmonary disease (COPD), the Shortness of Breath (SOB) with Daily Activities (SOBDA) questionnaire was developed as a patient-reported outcome instrument to evaluate the impact of therapy on SOB and assess how SOB affects daily activities.

Development of the SOBDA questionnaire consisted of three components. First, focus groups of patients with COPD were asked to describe their experiences of SOB with daily activities. A pool of items was drafted on the basis of information from the focus groups and literature reviews, and then discussed among instrument development and clinical experts. Cognitive debriefing interviews of patients were conducted to assess the draft item pool, and their feedback was used to develop newer versions of the questionnaire. Input was also sought from the Food and Drug Administration, patients, and clinicians.

Forty patients participated in seven focus groups. The terms most often used to describe SOB were "short of breath" or "difficulty breathing." Patients were clearly able to distinguish SOB from chest congestion and wheezing, other common symptoms associated with COPD. The resulting item pool contained 37 items to assess SOB associated with everyday activities, and concept saturation was reached. Thirty-seven patients participated in the subsequent cognitive debriefing interviews. Patients found the items clear and easy to understand with relevance to their everyday experiences, and easy to use in an electronic format.

Instructions and response options to the SOBDA questionnaire were well understood by patients with COPD, and item relevance was confirmed. Prospective validation and item reduction studies are highly anticipated.