The optimal short version of the Zarit Burden Interview for dementia caregivers: diagnostic utility and externally validated cutoffs

Objectives: Using a sample of dementia caregivers, we compared the diagnostic utility of the various short versions of the Zarit Burden Interview (ZBI) with the original scale to identify the most optimal one. Next, we established externally validated cutoffs for the various ZBI versions using probable depression cases as a reference standard. Methods: Caregivers (N = 394; 236 males; Age(mean) = 56 years) were administered the ZBI and a self-report depression measure. Participants who exceeded the cutoff for the latter were identified as probable depression cases. For each of the ZBI versions, a receiver operating characteristic (ROC) curve was plotted against probable depression cases. The area under these ROC curves between the short versions and the original were then compared using a non-parametric approach. Results: Compared to the original ZBI, the AUROC were similar for the 6-item, 7-item, and two 12-item versions, but significantly worse for the other short variants. The sensitivity and specificity of the cutoffs for all ZBI versions ranged from 77.3% to 85.2% and 60.1% to 79.8%, respectively. Conclusions: The original ZBI had good utility in identifying probable depression in caregivers, while the 6-item variant can be a useful alternative when short versions are preferred.