Development and psychometric evaluation of a self-management behaviours scale in rheumatoid arthritis patients (RA-SMBS)

Background Self-management behaviours can be crucial to improving disease symptoms and health outcomes in rheumatoid arthritis (RA) patients. Currently, the tools available for measuring self-management behaviours in RA patients are either generalized for patients with chronic diseases, which lack specificity or have poor reliability in the only specific scale—self-care behaviours scale (SCBS). The aim of this study was to develop a self-management behaviours scale for RA patients and evaluate its psychometric properties. Methods The study included two steps: scale development and the psychometric evaluation. The items were developed from a literature review, in-depth individual interviews, nominal group technique, Delphi expert consultation, and a pilot test. For the psychometric evaluation, a sample of 561 patients with RA was recruited. Item analysis, content validity, exploratory and confirmatory factor analysis, convergent and discriminant validity, and internal consistency reliability were conducted to examine the psychometric properties of the RA-SMBS. Results The final scale consists of 23 items with 4 dimensions, including medication management, exercise and joint protection, resource utilization and emotional management, and symptom management. The content validity index was 0.78. Exploratory factor analysis explained 61.89% of the total item variance. Confirmatory factor analysis indicated that the RA-SMBS fit well. Good internal consistency reliability was demonstrated (Cronbach's alpha = 0.908), and the test–retest reliability was found to be acceptable (ICC = 0.628, r = 0.780). Conclusions The scale has good content validity, construct validity, and internal consistency reliability. It can be used to assess the level of self-management behaviours in RA patients.