Psychometric evaluation of the Dysphagia Symptom Questionnaire for adults and adolescents with eosinophilic esophagitis

Abstract

Background

Eosinophilic esophagitis (EoE) is a chronic, inflammatory disease of the esophagus leading to symptoms of esophageal dysfunction; dysphagia is the most common symptom experienced by adults and adolescents.

Objective

We sought to perform a psychometric evaluation of the Dysphagia Symptom Questionnaire (DSQ), a patient-reported outcome measure for patients with EoE.

Methods

Using baseline and week 24 data from the randomized, interventional, multinational phase 3 R668-EE-1774 trial (NCT03633617), the measurement properties of the DSQ—including reliability, construct and known-groups validity, responsiveness, and interpretation of change—were evaluated.

Results

The analysis population comprised 239 patients with EoE (age [mean ± SD], 28.1 ± 13.14 years; 63.6% male; 90.4% White). Intraclass correlation coefficients of 0.92 and 0.97 exceeded the acceptable reliability threshold (≥0.70). Construct validity correlations with EoE symptom and impact measures were moderate at baseline (|r| = 0.44-0.55) and week 24 (|r| = 0.55-0.69), and the DSQ biweekly total score discriminated among groups defined by disease severity. Analyses exploring interpretation of change from baseline on the DSQ biweekly total score indicated thresholds for within-patient improvement ranging from 9 to 23 points; a within-patient improvement from baseline of 13 points or greater could be considered clinically meaningful.

Conclusions

This analysis confirmed that the DSQ has acceptable distributional properties, test-retest reliability, construct validity, and ability to detect change. Therefore, the DSQ is a valid and reliable measure to assess the patient-reported symptom of dysphagia among adult and adolescent patients with EoE in the context of a clinical trial setting.