Psychometric Characteristics of the Caregiver Contribution to Self-care of Chronic Illness Inventory

Aim: The purpose of the this study was to test the factorial structure, internal consistency reliability and concurrent validity of the Caregiver Contribution to Self-Care Chronic Illness Inventory.

Background: Existing measures of caregiver contribution to self-care are disease-specific or behaviour-specific; no generic measures exist.

Design: A cross-sectional study.

Method: Between April 2017 - December 2018, we enrolled a convenience sample of 358 patients with chronic illnesses and their caregivers. Patients completed the Self-Care of Chronic Illness Inventory while caregivers completed the Caregiver Contribution to Self-Care of Chronic Illness Inventory, a modification of the Self-Care of Chronic Illness Inventory, which includes three scales as follows: the Caregiver Contribution to Self-Care Maintenance, the Caregiver Contribution to Self-Care Monitoring and the Caregiver Contribution to Self-Care Management. Of each scale, we tested the factorial structure with confirmatory factor analysis and reliability with the factor score determinacy coefficient, the global reliability index for multidimensional scale and Cronbach's alpha. Also, we used Pearson's correlations for concurrent validity purposes.

Results: Confirmatory factor analysis supported the two-factor structure of the Caregiver Contribution to Self-Care Maintenance and Management scales and the one-factor structure of the Caregiver Contribution to Self-Care Monitoring scale. A simultaneous confirmatory factor analysis on the combined set of items supported the more general model (Comparative Fit Index = 0.933). Reliability estimates ranged between 0.701 and 0.961 across the three scales. Concurrent validity of Caregiver Contribution to Self-Care of Chronic Illness Inventory with the Self-Care of Chronic Illness Inventory was not sufficiently supported since weak correlations were found.

Conclusion: The Caregiver Contribution to Self-Care of Chronic Illness Inventory is valid and reliable and can be used in clinical practice and research.

Impact: The Caregiver Contribution to Self-Care of Chronic Illness Inventory is an useful instrument to evaluate the extent to which caregivers contribute to patient self-care in chronic illnesses.