Meaningful patient engagement in inflammatory arthritis: development of the Patient Motivation Questionnaire.

The objective of this study is to develop a questionnaire for evaluating the patient's "motivation" and assess the psychometric properties of that measure in patients with chronic inflammatory arthritis. Using Rasch analysis and questions item pool, content analysis, and semi-structured group discussion, the questionnaire was developed including 10-item scale (0-10 on VAS scale). Construct validity was assessed by correlating the questionnaire score to parameters of disease activity (DAS-28, ASDAS, and DAPSA scores), functional disability, quality of life, patient self-helplessness measure, as well as the patients' compliance to therapy. Reliability and comprehensibility and sensitivity to change were also assessed. The questionnaire was assessed in 432 RA, 415 psoriatic arthritis patients, and 232 ankylosing spondylitis patients. Dimensionality analysis revealed a 1-factor solution, explaining 98% of the total variance. It showed acceptable validity as it correlated significantly with disease activity measures: DAS-28: r = -0.85, ASDAS: r = -0.86, and DAPSA: r = -0.89. It also correlated significantly with functional disability score: r = -0.91, QoL: r = -0.90, as well as patient self-helplessness: r = -0.88. The questionnaire was reliable (Cronbach's alpha 0.958) and had no misfitting items. In addition, it was comprehensible (9.4) and sensitive to change (p < 0.01). The patient motivation score showed significant (p < 0.01) variation with the medication compliance. The measure is a patient-reported tool that is valid, reliable, comprehensible, and unidimensional scale that reflects the patients' motivation and engagement. The measure has good psychometric properties indicating that it can be used at the individual patient level to tailor management and monitor changes.