Discrepancies Between Community-Dwelling Individuals with Dementia and Their Proxies in Completing the Cornell Scale for Depression in Dementia: A Secondary Data Analysis

BACKGROUND: Depressive symptoms are common in people with dementia. PURPOSE: This study examined the discrepancies in the ratings of depressive symptoms between people with dementia and their family caregivers, and the extent to which these discrepancies varied according to the functional status of people with dementia. PARTICIPANTS AND METHODS: This study is a cross-sectional secondary analysis. Twenty-five people living with dementia (“participants”) and their family caregivers (“proxies”) participated as pairs in the study (participant mean age = 71.36, SD = 8.63; proxy mean age = 67.54, SD = 11.46). Data were collected in Victoria, Australia between May 2018 and May 2019. Participants were administered a semi-structured interview comprising the Cornell Scale for Depression in Dementia (CSDD). Proxies independently completed the CSDD and the Functional Activities Questionnaire (FAQ). A paired sample t-test was used to investigate differences in CSDD scores between participants and proxies. Kendall’s tau-b correlation was used to examine the relationship between FAQ scores and discrepancy scores of CSDD. Participants were then classified into either low or high functional impairment. Mann–Whitney U-test was used to examine whether the discrepancy scores of CSDD were similar between these two groups. Intraclass correlation coefficients were calculated to indicate the level of agreement between participants and proxies in each group. RESULTS: The CSDD scores of participants were significantly lower than proxies. The size of the discrepancy in CSDD scores was positively correlated with FAQ scores. The “high functional impairment” group had larger discrepancy scores and a lower level of agreement than the “low functional impairment” group. CONCLUSION: The findings highlighted that relying on proxy CSDD scores may not reflect estimates of depressive symptoms by people with dementia. Hence, both perspectives need to be taken into account, particularly when the level of functional impairment in dementia is advanced.