Development of the modified Daily Symptom Diary (mDSD): a patient-reported outcome measure of dysphagia for eosinophilic esophagitis.

Objective: Eosinophilic esophagitis (EoE) is a progressive, chronic, Type 2 inflammatory and fibrostenotic disease causing dysphagia among other symptoms. Patient-reported outcome (PRO) measures are essential for the assessment of EoE symptoms. One such PRO measure is the Daily Symptom Diary (DSD), but its content validity has not been established. This study modified the DSD based on participants' feedback and assessed the content validity of the modified DSD (mDSD).

Methods: Combined qualitative concept elicitation and cognitive interviews were conducted with adolescents (12-17 years) and adults (18-75 years) with a clinician-confirmed EoE diagnosis. Participants were asked about their symptoms and impacts. They were then asked to complete the DSD/mDSD and discuss its comprehensibility, relevance, and ease-of-use.

Results: Twenty-one patients (n = 17 adults [mean age: 33.1 years, n = 13 males], n = 4 adolescents [mean age: 15.5 years, n = 3 males]) participated. The most frequently mentioned EoE symptoms were food getting stuck in the throat (n = 21), vomiting/throwing up (n = 17), and difficulty swallowing (n = 13). Following feedback from the first four interviews, the DSD was modified to include two more items, including a separate item for food going down slowly; the mDSD was used thereafter. Participants noted that the mDSD captured their major symptoms (n = 20) and was clear and understandable (n = 20). When asked about meaningful change in symptoms, eight (40%) would consider a reduction of 1-2 days with dysphagia per 7-day period as meaningful.

Conclusion: This study confirms the content validity of the mDSD. The measure captured the symptom experience of adolescents and adults with EoE and was relevant and easy to use, supporting its use in clinical research.