E Vellone

Dimensionality and Reliability of the Self-Care of Heart Failure Index Scales: Further Evidence From Confirmatory Factor Analysis

The Self-Care of Heart Failure Index (SCHFI) is used widely, but issues with reliability have been evident. Cronbach alpha coefficient is usually used to assess reliability, but this approach assumes a unidimensional scale. The purpose of this article is to address the dimensionality and internal consistency reliability of the SCHFI. This was a secondary analysis of data from 629 adults with heart failure enrolled in three separate studies conducted in the northeastern and northwestern United States. Following testing for scale dimensionality using confirmatory factor analysis, reliability was tested using coefficient alpha and alternative options. Confirmatory factor analysis demonstrated that: (a) the Self-Care Maintenance Scale has a multidimensional four-factor structure; (b) the Self-Care Management Scale has a two-factor structure, but the primary factors loaded on a common higher-order factor; and (c) the Self-Care Confidence Scale is unidimensional. Reliability estimates for the three scales, obtained with methods compatible with each scales dimensionality, were adequate or high. The results of the analysis demonstrate that issues of dimensionality and reliability cannot be separated. Appropriate estimates of reliability that are consistent with the dimensionality of the scale must be used. In the case of the SCHFI, coefficient alpha should not be used to assess reliability of the self-care maintenance and the self-care management scales, due to their multidimensionality. When performing psychometric evaluations, we recommend testing dimensionality before assessing reliability, as well using multiple indices of reliability, such as model-based internal consistency, composite reliability, and omega and maximal reliability coefficients.

Self-care in heart failure patients: major results of a 7-year research program in Italy

Self-care improves patients’ outcomes in heart failure (HF). In this article we report the main results of a 7-year research program conducted in Italy. First, we established validity and reliability of the Self-Care of HF Index v.6.2 and the Caregiver Contribution to Self-Care of HF Index in the Italian population. Second, we tested the situation-specific theory of HF self-care that showed adequate fit to the data. Third, we showed in a sample of 1.192 HF patients that only about the 20% of them performs adequate self-care. Forth, we described caregiver contribution to self-care in a sample of 515 HF caregivers and we showed a low level of caregiver contribution to HF self-care. Fifth, we showed that patients and caregivers influence each other self-care. Six, we found that self-care confidence mediates between cognition and self-care, and comorbidity moderates between self-care confidence and self-care. Intervention studies are needed to improve self-care in Italian HF patients.