Objectives: The Zarit Caregiver Burden Scale, translated and validated into Spanish, is sensitive to the application of a Psychoeducational Intervention Program (PIP) for the prevention and reduction of burden in caregivers of Alzheimer's disease (AD) patients (EDUCA study). The data obtained in EDUCA was used to reanalyse its psychometric properties and the cut-off points of the Zarit scale.
Methods: The scale was administered to 115 caregivers of patients with AD who were randomised to receive a PIP or standard care for four months. Internal reliability and a factorial analysis of principal components were assessed, and the impact of PIP on each of the subscales was evaluated. A cut-off point was defined for the Zarit scale to identify the caregivers most sensitive to receiving a PIP.
Results: A good internal reliability (Cronbach alpha coefficient of 0.92) was obtained, with three principal components (burden, competency and dependence) explaining 54.75% of the variance. The application of PIP showed statistically significant differences versus standard care for the dependence subscale (p = 0.0082) (p = 0.062 for the burden scale). The Zarit scale cut-off points which combine better sensitivity and specificity were 56/57 and 59/60, for the 5/6 and 6/7 cut-off points of the General Health Questionnaire (GHQ-28) scale, respectively.
Conclusions: This study confirms the good psychometric properties of the Zarit scale found in previous studies. The dependence component appeared to be most influenced by the application of a PIP in the clinical trial. Caregivers with a Zarit scale score of 60 or more benefit most from the PIP.