Validity and reliability of the caregiver contribution to self-care of heart failure index.
BACKGROUND
Caregivers make an important contribution to the self-care of patients with heart failure (HF), but few instruments are available to measure this contribution.


OBJECTIVE
The objective of this study was to test the psychometric properties of the Caregiver Contribution to Self-care of Heart Failure Index (CC-SCHFI), an instrument derived from the Self-care of Heart Failure Index version 6.2. The CC-SCHFI measures the contribution of caregivers to the self-care maintenance and self-care management of HF patients, as well as their confidence in their ability to contribute to the patients' HF self-care.


METHODS
A cross-sectional design was used to study 291 Italian caregivers whose HF patients were cared for in 17 cardiovascular centers across Italy. Caregivers completed the CC-SCHFI and a sociodemographic questionnaire. Caregivers were retested on the CC-SCHFI 2 weeks later to assess test-retest reliability.


RESULTS
Most caregivers were women (66%) with a mean age of 59 years. First- and second-order confirmatory factor analysis (CFA) for each CC-SCHFI scale showed good model fit: χ2 = 37.22, P = .08, Comparative Fit Index (CFI) = 0.97, Non-Normed Fit Index (NNFI) = 0.96 for caregiver contribution to self-care maintenance (second-order CFA); χ2 = 14.05, P = .12, CFI = 0.96, NNFI = 0.93 for caregiver contribution to self-care management (first-order CFA); and χ2 = 10.63, P = .15, CFI = 0.99, NNFI = 0.98 for caregiver confidence in contributing to self-care (second-order CFA). The CC-SCHFI was able to discriminate statistical and clinical differences between 2 groups of caregivers who had received or not received HF self-care education. Internal consistency reliability measured by factor score determinacy was more than .80 for all factors and scales except for 1 factor in the caregiver contribution to self-care management scale (.65). Test-retest reliability computed by intraclass correlation coefficient was high (>0.90) for most factors and scales.


CONCLUSION
The CC-SCHFI showed good psychometric properties of validity and reliability and can be used to measure the contribution of caregiver to HF patient self-care.