Development and validation of a self-efficacy scale for use in British patients with rheumatoid arthritis (RASE).

Objective: Current arthritis self-efficacy scales have attracted some criticism. Therefore, the aim of this study was to develop and validate a measure of self-efficacy for use in British rheumatoid arthritis patients [Rheumatoid Arthritis Self-efficacy (RASE) scale].

Methods: Phase I: item generation of self-management strategies by rheumatology professionals and patients to create a pilot RASE. Phase II: examination of the internal structure (n=88) using correlation coefficients and principal component analysis (PCA) to create the final RASE. Phase III: reliability in 23 patients. Phase IV: comprehension, construct validity and sensitivity to change in 48 rheumatoid arthritis patients undergoing a self-management programme, using correlation coefficients, PCA and inter-item correlation.

Results: Phase I: of 166 self-management items generated, 100 commonly cited items were selected for the pilot RASE. Phase II: using a correlation matrix and PCA, a 28-item RASE was created. Phase III: good 4-week reliability was seen (r=0.889, P<0.001). Phase IV: the final RASE was shown to be independent of mood, disease status and disability and weakly associated with other self-efficacy scales (r=0.313, P<0.05). The RASE was sensitive to change following an education programme (+5.167, P<0.025), and was associated with behaviour initiation (r=0.35, P<0.01).

Conclusions: Careful construction means that the RASE examines beliefs in potential ability to perform tasks, rather than actual ability, performance or outcome expectancy. It shows good face validity and reliability, plus reasonable construct validity and sensitivity. Further studies are needed to support the validation of this new scale.