Cross-cultural adaptation and psychometric validation of the Persian version of the Cardiac Rehabilitation Barriers Scale (CRBS-P)

OBJECTIVES: This study aimed to translate, cross-culturally adapt and psychometrically validate a Persian version of the Cardiac Rehabilitation Barriers Scale (CRBS-P) and to identify the main barriers in an Iranian setting. SETTING: Afshar cardiac rehabilitation (CR) centre, affiliated with the Yazd University of Medical Sciences, in the centre of Iran. DESIGN: This was a multimethod study, culminating in a cross-sectional survey. PARTICIPANTS: Inpatient CR graduates who did not attend their initial outpatient CR appointment. METHOD: The 21-item CRBS was translated and cross-culturally adapted in accordance with best practices; an expert panel considered the items and previous non-attending patients were interviewed via phone to refine the scale. Next, structural validity was assessed; participants were invited to complete the CRBS on the phone between March 2017 and February 2018. Using exploratory factor analysis (EFA) with principal component analysis extraction and oblique rotation. Second, confirmatory factor analysis (CFA) was used to verify the results; several goodness-of-fit indices were considered. The internal consistency and 3-week test–retest reliability of the scale (5% subsample) were evaluated using Cronbach’s α and intraclass correlation (ICC), respectively. RESULTS: Face, content and cross-cultural validity were established by the experts and patients (n=50). One thousand and one hundred (40.7%) of the 2700 patients completed the CRBS-P. Structural validity was established by EFA (Bartlett’s test p<0.001; =0.759) and confirmed by the CFA; a four-factor solution with 18 items accounting for 61.256% of variance had the best fit (χ(2)/df=3.206, root mean square error of approximation=0.061 and Comparative Fit Index=0.959). The internal consistency and test–retest reliability (n=42) of the scale were acceptable (ICC=0.743 95% CI (0.502 to 0.868); overall α=0.797). The top barriers were not knowing about CR, cost and lack of encouragement from physicians. CONCLUSION: The four-factor, 18-item CRBS-P had good psychometric properties, and hence can be reliably and validly used to measure CR barriers in Iran and other Persian-speaking populations.