Measuring burden in dementia caregivers: Confirmatory factor analysis for short forms of the Zarit Burden Interview.

INTRODUCTION: To examine the psychometric properties of different short versions of the Zarit Burden Interview (ZBI), and to find an efficient and valid short version for clinical use among dementia caregivers.

MATERIALS AND METHODS: A total of 270 Taiwanese dementia caregivers filled out the full form of the ZBI, which contains 22 items. Using the 22-item ZBI, we used confirmatory factor analysis (CFA) to calculate the fit indices of all proposed short versions with various items to determine useful short versions. Additional associations between each useful short version and informal care hours, as well as subjective financial situations, were examined to understand their concurrent validity.

RESULTS: Based on the CFA results, three short versions of the ZBI, performed excellently (4-item version: comparative fit index [CFI]=1.000, Tucker-Lewis index [TLI]=1.035, standardized root mean square residual [SRMR]=0.019, and root mean square error of approximation [RMSEA]=0.000; 8-item version: CFI=0.970, TLI=0.958, SRMR=0.045, and RMSEA=0.065; 12-item version: CFI=0.959, TLI=0.950, SRMR=0.053, and RMSEA=0.075). In addition, the 12-item ZBI, as compared with other versions, had a higher correlation with the number of informal care hours. The 12-item ZBI was also highly correlated with the original 22-item ZBI (r=0.952).

CONCLUSIONS: We found the 12-item ZBI to be a promising measure for healthcare providers to assess the burden of dementia caregivers quickly and efficiently.