Background: The validity of self-reported quality-of-life (QoL) assessments of people with dementia (PWD) is a critical issue. We designed this study to determine the non-cognitive factors that are associated with self-reported QoL and PWD QoL as rated by family caregivers.
Methods: Using a cross-sectional study, we assessed QoL of 41 people with mild Alzheimer's disease (AD). The individuals with AD and their family caregivers completed the Quality of Life in Alzheimer's Disease Scale (QoL-AD), the Assessment Scale of Psychosocial Impact of the Diagnosis of Dementia (ASPIDD), the Mini-Mental State Examination (MMSE), the Clinical Dementia Rating (CDR) scale, the Cornell Scale for Depression in Dementia (CSDD), the Pfeffer Functional Activities Questionnaire (FAQ), and the Zarit Burden Interview (ZBI). Univariate and multivariate regression analyses were conducted to examine the contribution of the various cofactors.
Results: We observed a significant difference (t = 3.292, p < 0.01, d = 0.727) in the QoL measures of PWD after comparing self-reported assessments with the assessments of family caregivers. Linear regression analysis demonstrated that awareness of disease was related to PWD QoL-AD scores. Both the education levels of family caregivers and the depressive symptoms in PWD were related to the family caregivers’ ratings of PWD QoL.
Conclusions: The difference between self-reported QoL and family caregivers’ ratings of QoL in people with mild dementia indicated that cognitive impairment was not the primary factor that accounted for the differences in the QoL assessments. Our findings suggested that non-cognitive factors, such as awareness of disease and depressive symptoms, played an important role in the differences between the self-reported AD QoL ratings and the caregivers’ AD QoL ratings. A major implication is that discrete measures such as cognition or level of function are likely to miss important factors that influence QoL.