Psychometrics of the Zarit Burden Interview in Caregivers of Patients With Heart Failure.

BACKGROUND Identification of family caregivers who are burdened by the caregiving experience is vital to prevention of poor outcomes associated with caregiving. The Zarit Burden Interview (ZBI), a well-known measure of caregiving burden in caregivers of patients with dementia, has been used without being validated in caregivers of patients with heart failure (HF). PURPOSE The purpose of this study is to examine the reliability and validity of the ZBI in caregivers of patients with HF. METHODS A total of 124 primary caregivers of patients with HF completed survey questionnaires. Caregiving burden was measured by the ZBI. Reliability was examined using Cronbach's α and item-total/item-item correlations. Convergent validity was examined using correlations with the Oberst Caregiving Burden Scale. Construct validity was demonstrated by exploratory factor analysis and known hypothesis testing (ie, the hypothesis of the association between caregiving burden and depressive symptoms). RESULTS Cronbach's α for the ZBI was .921. The ZBI had good item-total (r = 0.395-0.764) and item-item (mean r = 0.365) correlations. Significant correlations between the ZBI and the Oberst Caregiving Burden Scale (r = 0.466 for the caregiving time subscale and 0.583 for the caregiving task difficulty subscale; P < .001 for both) supported convergent validity. Four factors were identified (ie, consequences of caregiving, patient's dependence, exhaustion with caregiving and uncertainty, and guilt and fear for the patient's future) using factor analysis, which are consistent with previous studies. Caregivers with high burden scores had significantly higher depressive symptoms than did caregivers with lower burden scores (7.0 ± 6.8 vs 3.1 ± 4.3; P < .01). CONCLUSION The findings provide evidence that the ZBI is a reliable and valid measure for assessing burden in caregivers of patients with HF.