Evaluation of a Swedish version of the arthritis self-efficacy scale in people with fibromyalgia

The major purpose of this study was to determine the utility and construct validity of the Swedish version of the Arthritis Self-Efficacy Scale (ASES-S). Ninetynine women with fibromyalgia (FS) were included in a randomized, controlled trial of fibromyalgia efficacy-based self-management education and physical training. Several self-report instruments were used to evaluate the outcome of the intervention. Evidence of construct validity of the ASES-S was revealed in the factor analysis which produced a three factor solution similar to previous results. Significant correlations between ASES-S and pre and post health status measures were consistent with theoretically derived hypotheses, further testifying to construct validity. Multiple regression analyses confirmed that pretest ASES-S was the strongest predictor of posttest ASES-S. The results indicated that the intervention had produced a significant change in ASES-S and that this positive change in self-efficacy was associated with changes in health status. In conclusion, this study has shown the ASES-S to be a valid measure of treatment effects also for patients with FS.