Development and field testing of a novel patient-reported outcome measure of dysphagia in patients with eosinophilic esophagitis

Background Dysphagia is the hallmark of eosinophilic esophagitis (EoE), but no validated dysphagia instruments in this population exist. Aim To develop and field test a patient-reported outcome (PRO) for dysphagia in subjects with EoE. Methods This was a multi-centre/multi-phase prospective study. The first phase developed a dysphagia questionnaire using qualitative methods. The second phase was a 30-day field trial to test the instrument and assess content validity. Adolescents and adults with EoE, active symptoms of dysphagia and oesophageal eosinophilia (15eosinophils per high-power field) were enrolled. Solid-food-avoidance days, dysphagia days and actions taken to get relief were recorded. A dysphagia score was calculated and compared to the Straumann Dysphagia Instrument (SDI). Results Ten adolescents and 10 adults were included in the first phase and the Dysphagia Symptom Questionnaire (DSQ), a three-item daily electronic diary, was developed. In the second phase, 35 subjects finished the field trial (18 adults, 17 adolescents, mean age 24, 54% male, 95% white, 54% currently on topical corticosteroids). The median number of dysphagia days per week was 2 for adolescents vs. 4 for adults (P<0.001), and 2 for those on topical steroids vs. 4 for those not on topical steroids (P<0.001). The DSQ score strongly correlated with the number of dysphagia days (R=0.96; P<0.001) and the SDI (R=0.77; P<0.001). Conclusions The DSQ, a three-question patient-reported outcome, was successfully developed and field tested. The DSQ had content validity and the score accurately measured dysphagia frequency and intensity. The Dysphagia Symptom Questionnaire is suitable for use in clinical trials of EoE patients with dysphagia.