What explains differences between dementia patients' and their caregivers' ratings of patients' quality of life?

OBJECTIVE: The authors assessed the magnitude of discrepancy between patients' and caregivers' ratings of the patients' quality of life and sought to determine whether the discrepancies are associated with patient characteristics, caregiver characteristics, or the type of relationship between the patient and caregiver.
METHODS: A sample of 91 patients with mild-to-moderately severe dementia and their primary family caregiver rated five domains of the patients' subjective quality of life.
RESULTS: Agreement between patients and caregivers was low. Caregivers rated patients' quality of life lower than patients rated their own in all five domains. Discrepancies between patients' and caregivers' ratings were not associated with the patients' cognitive performance, level of functioning, nor caregivers' reports of aggressive, attention-seeking, or sexually inappropriate behaviors, nor whether the caregiver lived with or was married to the patient. However, discrepancies were associated with level of caregiver burden and the patients' report of depressive symptoms. Patients with depression reported low quality of life, which matched caregivers' low rating of patients' quality of life. Caregivers who reported higher levels of burden rated patients' quality of life lower than did patients in all five domains of quality of life.
CONCLUSIONS: Discrepancies between dementia patients' and their caregivers' ratings of the patients' quality of life are associated with increased levels of caregiver burden, rather than lower levels of patients' functioning. The results of this study support the direct assessment of mild-to-moderate dementia patients about their subjective quality of life.