Development, psychometric evaluation and cognitive debriefing of the rheumatoid arthritis symptom and impact questionnaire (RASIQ)

Background Rheumatoid arthritis (RA) is a chronic inflammatory disease often associated with persistent pain. There is a need for a patient-reported outcome measure (PROM) that is rooted in the patient experience and psychometrically validated. We describe the development of the Rheumatoid Arthritis Symptom and Impact Questionnaire (RASIQ), a novel PROM with potential to record key symptoms and impacts of RA with a 24-h recall period. Results A literature review identified RA concepts that patients considered most important to their disease experience, including pain, fatigue, joint swelling and stiffness. From this, an initial item pool (33 items; 27 related to symptoms, 6 related to impacts) was developed with a recall period of 24 h. Two rheumatologists evaluated each item’s relevance, and the second version of the RASIQ was refined (29 items; 21 related to symptoms, 8 related to impacts). Next, three rounds of cognitive debriefing interviews were conducted with patients with RA (n = 15 overall). The RASIQ was revised to remove items deemed irrelevant or redundant, leaving 16 items measuring symptoms (joint pain, energy/tiredness, joint stiffness) and impacts (rest, sleep). A parallel series of semi-structured concept elicitation interviews (n = 30) facilitated the design of a conceptual model of RA symptoms, impacts and treatment experiences. Post-hoc comparison of the model with RASIQ revealed that all items selected were among the most important and relevant symptoms and impacts for patients. A final round of cognitive debriefing interviews (n = 12) confirmed that the final 16-item RASIQ was relevant and easy to understand, with no further changes recommended. Psychometric evaluation using data from two Phase II RA clinical trials confirmed a 3-factor structure, as well as the reliability and validity of the scale scores, and the ability of RASIQ to detect changes in symptoms and impacts when administered at specific study timepoints, using a 24-h recall period. Conclusions RASIQ is a novel, 16-item PROM developed with substantial patient input. Results from concept elicitation, cognitive debriefing, and psychometric evaluation confirmed the validity of the instrument, which has the potential to measure symptoms and impacts through a 24-h recall period and complement existing disease activity instruments with longer recall periods.