The Dermatomyositis Disease Symptom Questionnaire (DM-DSQ): A Measure to Assess the Patient Experience of Dermatomyositis Symptoms

Objective: Dermatomyositis (DM) symptoms negatively impact the quality of life of individuals living with the disease. Disease-specific, patient-reported outcome (PRO) instruments are needed to assess symptoms important to individuals with DM. This study conceptualized patient DM experience and disease activity definition, which refined development of a novel PRO instrument capturing patient-reported symptoms, the Dermatomyositis Disease Symptom Questionnaire (DM-DSQ).
Methods: An observational, qualitative study was conducted with 30 individuals with DM (age ≥18 years) in the US. A 1-hour semi-structured interview, including concept elicitation and cognitive debriefing, was conducted with each participant. Inductive coding was used to identify concepts; a saturation analysis was conducted to confirm sample size. Concepts from transcripts were used to refine the preliminary conceptual model and DM-DSQ items.
Results: Concept elicitation analysis findings included disease symptoms (e.g., muscle weakness) and functional impacts (e.g., walking). The analysis achieved conceptual saturation: the first 5 interviews uncovered most of the concepts. During cognitive debriefing of the DM-DSQ, participants found the items relevant, comprehensive, and easily understood (except for “skin sensitivity in sunlight”). The revised DM-DSQ content preliminarily appears valid in the patient population surveyed, pending further additions and debriefing based on refinement of the preliminary conceptual disease model and items.
Conclusions: The DM-DSQ is being used in a phase 2 clinical trial and could become a valuable tool for studies evaluating PROs in patients with DM. Preliminary results indicate its content validity; extensive psychometric analysis using clinical trial data will determine its ability to capture symptoms for patients with DM.