Assessing Asthma Symptoms in Adolescents and Adults: Qualitative Research Supporting Development of the Asthma Daily Symptom Diary

Background: Despite the widespread availability of patient-reported asthma questionnaires, instruments developed in accordance with present regulatory expectations are lacking. To address this gap, the Patient-Reported Outcome (PRO) Consortium's Asthma Working Group has developed a patient-reported asthma daily symptom diary (ADSD) for use in clinical research to assess outcomes and support medical product labeling claims in adults and adolescents with asthma. Objectives: To summarize the qualitative research conducted to inform the initial development of the ADSD and to provide evidence for content validity of the instrument in accordance with the Food and Drug Administration's PRO Guidance. Methods: Research informing the initial development and confirming the content validity of the ADSD is summarized. This comprised a review of published qualitative research, semi-structured concept elicitation interviews (n = 55), and cognitive interviews (n = 65) with a diverse and representative sample of adults and adolescents with a clinician-confirmed diagnosis of asthma in the United States to understand the asthma symptom experience and to assess the relevance and understanding of the newly developed ADSD. Results: From the qualitative literature review and concept elicitation interviews, eight core asthma symptoms emerged. These were broadly categorized as breathing symptoms (difficulty breathing, shortness of breath, and wheezing), chest symptoms (chest tightness, chest pain, and pressure/weight on chest), and cough symptoms (cough and the presence of mucus/ phlegm). Conceptual saturation was achieved and differences in the experience of participants according to socio-demographic or clinical characteristics were not observed. Subsequent testing of the ADSD confirmed participant relevance and understanding. Conclusions: The ADSD is a new patient-reported asthma symptom diary developed in accordance with the Food and Drug Administration's PRO Guidance. Evidence to date supports the content validity of the instrument. Item performance, reliability, and construct validity will be assessed in future quantitative research.