Original and abbreviated Zarit caregiver burden scales. Validation in Chile

Background: Six percent of the Chilean population has a disability requiring assistance with daily-living-activities and 69% of these individuals are cared by direct family members. The latter are, at risk of developing caregiver burden. Zarit scales are used to assess the severity of caregiver burden. Aim: To validate The original and abbreviated Zarit scales for caregiver burden. Material and methods: Two groups of interviewers applied the original and abbreviated Zarit scales, along with a single subjective indicator, for burden and surveys for depression, to 32 caregivers from an outpatient clinic in Melipilla, Chile. In 22 subjects, the instruments were applied again, four months later. Results: Both Zarit scales showed high correlation with The subjective indicator for burden and with depression (r =0.51 and 0.67, respectively), supporting its construct validity. The abbreviated scale bad a high correlation with The original scale (r =0.92), supporting its criterion validity. It bad a 100016 sensitivity, 77.7016, specificity, 86,6% positive predictive value and 100(116 negative predictive value to discriminate severe caregiver burden, using the original scale as standard. Both instruments showed high internal consistency (Cronbach alpha =0.84 and 0.87, respectively), inter-observer reliability (intraclass correlation coefficient =0.8.1 and 0.86, respectively) and stability reliability (Kappa test-retest =0.9.1 and 0.93, respectively). Conclusions: Both original and abbreviated Zarit burden scales are valid to assess caregivers burden in a Chilean context. The abbreviated scale seemed particularly useful for primary care (Rev Med Chile 2009; 137: 657-65).