Psychometric Properties of the Korean Version of the Perceived Therapeutic Efficacy Scale for Physical Activity in Adults With Type 2 Diabetes

Abstract

PURPOSE: The purpose of this study is to translate the Perceived Therapeutic Efficacy Scale (PTES) into Korean and investigate its validity and reliability. METHODS: The authors conducted a cross-sectional survey using baseline data from a randomized controlled study to psychometrically validate the PTES-Korean (PTES-K) among 108 adults with type 2 diabetes from an outpatient clinic at a university-affiliated hospital in Korea. The original PTES was forward-translated and back-translated to ensure translation equivalence of the PTES-K. Structured questionnaires were used for psychometric evaluation; exploratory and confirmatory factor analysis assessed validity, and Cronbach's alpha coefficient and intraclass correlation coefficient (ICC) were used for reliability. RESULTS: The interitem correlation analyses revealed that 5 items were redundant; thus, the scale was reduced to 5 items. A 1-factor model explained 76.85% of the variance; confirmatory factor analysis showed that this model adequately fit the data. The ICC for test-retest reliability was .78; Cronbach's alpha was .92. The PTES-K showed significant associations with the scores of diabetes self-care activities for physical activity, quality of life, and depressive symptoms. Participants with good glycemic control and regular physical activity tended to have a higher score on the PTES-K than their counterparts, demonstrating known-groups validity. CONCLUSIONS: The cross-cultural applicability, reliability, and validity of the PTES-K were confirmed. The PTES-K may be used in clinical settings to examine the potential role of perceived therapeutic efficacy for physical activity in enhanced glycemic control among patients with diabetes.