Psychometric properties of the Swedish Rheumatic Disease Empowerment Scale, SWE-RES-23.

INTRODUCTION: Empowerment is a central concept in both rheumatology and diabetes care. A Swedish empowerment instrument for patients with rheumatic diseases has not been created before now. The aim of the present study was to determine the psychometric properties of the Swedish Rheumatic Disease Empowerment Scale, SWE-RES-23, such as construct validity, internal consistency reliability, inter-item correlations and discriminant validity.
METHODS: The already existing instrument, the Swedish Diabetes Empowerment Scale (SWE-DES-23), was adapted for use in patients with rheumatic diseases. The adapted instrument was called the SWE-RES-23. In 2009, 260 patients with rheumatic diseases from a rheumatology unit in Sweden completed the instrument. Construct validity was tested by using exploratory factor analysis. Internal consistency reliability was tested by the use of Cronbach's α-coefficient. In order to determine unidimensionality of the empowerment subscales, inter-item correlations were calculated. To establish discriminant validity, an item about self-perceived health from the Short Form (SF) 36 was used in addition to the SWE-RES-23.
RESULTS: The exploratory factor analysis resulted in five factors (empowerment subscales) with eigenvalues >1, explaining 64.1% of the total variance: Goal achievement and overcoming barriers to goal achievement; Self-knowledge; Managing stress; Assessing dissatisfaction and readiness to change; and Support for caring. Cronbach's α values ranged from 0.59 to 0.91, and the value for the total score was 0.92.
CONCLUSION: The results support the possibility of adapting the SWE-DES-23 for use in patients with rheumatic diseases. The SWE-RES-23 shows acceptable psychometric properties, in terms of construct validity and internal consistency reliability. To validate the SWE-RES-23 fully, further studies are needed, with a focus on test-retest correlations.