Psychometric evaluation of the cardiac rehabilitation adherence scale in patients with coronary heart disease: an observational study.

Background: Cardiac rehabilitation has showed the potential to improve health outcomes of patients with coronary heart disease. However, the adherence of patients participating in cardiac rehabilitation is unsatisfactory due to some barriers. The quantitative instrument for measuring cardiac rehabilitation adherence is scarce. Hence, the purpose of this study was to develop a scientific tool and assess its psychometric properties in patients with coronary heart disease.

Material and methods: The psychometric properties of the revised scale were tested with 509 patients. Item analysis was conducted to evaluate the discrimination and homogeneity of the scale. Content validity was evaluated by content validity index and Exploratory factor analyses and confirmatory factor analyses were used to examine the factor structure of the scale. Reliability was evaluated by Cronbach's coefficients and split-half reliability coefficients.

Results: A scale covering five dimensions and thirty-three items was developed for evaluating cardiac rehabilitation adherence. The content validity index of the scale was 0.96. In exploratory factor analysis, a five-factor structure model was confirmed, explaining 71.255% of the total variation. In confirmatory factor analysis, the five- factor structure was supported by appropriate fitting indexes. In terms of reliability, the Cronbach's α coefficient of the scale was 0.909 and the spilt-half reliability coefficient of the scale was 0.765.

Conclusion: The newly developed self-completion scale is reliable and valid. It appears to be a sound instrument for nurses and a broader range of healthcare professionals to effectively evaluate the cardiac rehabilitation adherence.