Validity and reliability of the Zarit Burden Interview in assessing caregiving burden.

INTRODUCTION This study aims to validate the Zarit Burden Interview as an instrument to measure the level of burden experienced by caregivers of patients with dementia (PWD) in Singapore. MATERIALS AND METHODS Adult family caregivers of PWD were recruited from the ambulatory dementia clinic of a tertiary hospital and the Alzheimer's Disease Association. All subjects completed a battery of questionnaires which consisted of demographic questions and the following instruments: the Zarit Burden Interview (ZBI), Burden Assessment Scale (BAS), General Health Questionnaire (GHQ-28), Dementia Management Strategies Scale (DMSS), and the Revised Memory and Behaviour Problems Checklist (RMBPC). A subgroup of subjects also completed the ZBI for the second time 2 weeks after the fi rst survey. RESULTS A total of 238 subjects completed the survey. As hypothesised, the Zarit burden score was strongly correlated with BAS, GHQ-28, DMSS, and RMBPC scores (Pearson's correlation coefficient: 0.53 to 0.73); caregivers who undertook the major role in caregiving, had spent >1 year in caregiving, or experienced financial problems had higher Zarit burden scores than those who were not main carers, with ≤1 year of caregiving, or reported no/minimal financial problems, respectively. The Cronbach's alpha value for the ZBI items was 0.93; the intra-class correlation coefficient for the test-retest reliability of the Zarit burden score was 0.89 (n = 149). CONCLUSION The results in this study demonstrated that the Zarit Burden Interview is a valid and reliable instrument for measuring the burden of caregivers of PWD in Singapore.