Psychometric testing of the self-care of heart failure index

Abstract

BACKGROUND Self-care is believed to improve outcomes in heart failure (HF) patients. However, research testing this assumption is hampered by difficulties in measuring self-care. The purpose of this study was to evaluate the psychometric properties of a revised instrument measuring self-care in persons with HF, the Self-Care of Heart Failure Index (SCHFI). The SCHFI is a self-report measure comprised of 15 items rated on a 4-point response scale and divided into 3 subscales. METHODS AND RESULTS Psychometric testing was done using data from 760 HF patients (age 70.36 +/- 12.3 years, 51% male) from 7 sites in the United States. Reliability of the SCHFI (alpha.76) was adequate. Reliability of the Self-Care Maintenance subscale was lower than desired (alpha.56) but the reliability of the other subscales was adequate: Self-Care Management (alpha.70) and Self-Care Self-Confidence (alpha.82). Construct validity was supported with satisfactory model fit on confirmatory factor analysis (NFI=.69, CFI.73). Construct validity was supported further with significant total and subscale (all P <.05) differences between patients experienced with HF and those newly diagnosed, consistent with the underlying theory. CONCLUSION Low reliability of the Self-Care Maintenance subscale was expected because the items reflect behaviors known to vary in individuals. The reliability and validity of the SCHFI are sufficient to support its use in clinical research.