Translation and validation of the Dutch version of the Effective Consumer Scale (EC-17).

PURPOSE: The Effective Consumer Scale (EC-17) measures the skills of musculoskeletal patients in managing their own healthcare. The objectives of this study were to translate the EC-17 into Dutch and to further evaluate its psychometric properties. METHODS: The EC-17 was translated and cognitively pretested following cross-cultural adaptation guidelines. Two hundred and thirty-eight outpatients (52 % response rate) with osteoarthritis or fibromyalgia completed the EC-17 along with other validated measures. Three weeks later, 101 patients completed the EC-17 again. RESULTS: Confirmatory factor analysis supported the unidimensional structure of the scale. The items adequately fit the Rasch model and only one item demonstrated differential item functioning. Person reliability was high (0.92), but item difficulty levels tended to cluster around the middle of the scale, and measurement precision was highest for moderate and lower levels of skills. The scale demonstrated adequate test-retest reliability (ICC = 0.71), and correlations with other measures were largely as expected. CONCLUSION: The results supported the validity and reliability of the Dutch version of the EC-17, but suggest that the scale is best targeted at patients with relatively low levels of skills. Future studies should further examine its sensitivity to change in a clinical trial specifically aimed at improving effective consumer skills.

Further validation of the 5-item Perceived Efficacy in Patient-Physician Interactions (PEPPI-5) scale in patients with osteoarthritis.

OBJECTIVE: To examine the structural validity, internal consistency, test-retest reliability, and construct validity of the 5-item Perceived Efficacy in Patient-Physician Interactions (PEPPI-5) scale in patients with osteoarthritis (OA). METHODS: A cross-sectional sample of 224 outpatients with OA completed a survey containing the Dutch PEPPI-5 and other standardized measures assessing perceived health-management skills, general self-efficacy, social support, and health-related quality of life. A subsample of 100 patients completed the PEPPI-5 again approximately 3 weeks later. RESULTS: Confirmatory factor analysis demonstrated good fit for a unidimensional model of the PEPPI-5. Additionally, the scale showed high internal consistency (α=0.92) and fair test-retest reliability (ICC=0.68). As hypothesized, the PEPPI-5 was strongly correlated with perceived health-management skills, moderately with social support and psychosocial aspects of health, and not with physical aspects of health. Contrary to expectations, however, it was not correlated with general self-efficacy. CONCLUSION: The Dutch PEPPI-5 demonstrated adequate validity and reliability in patients with OA. PRACTICE IMPLICATIONS: The PEPPI-5 is a brief and appropriate tool for measuring self-efficacy of patients with OA to interact with their physicians. Additional research into its sensitivity to change is needed before it can be confidently recommended as an outcome measure in intervention studies.