The relationship between caregivers' global ratings of Alzheimer's disease patients' quality of life, disease severity, and the caregiving experience

OBJECTIVES: To compare caregivers' ratings of Alzheimer's disease (AD) patients' global quality of life (QOL) using direct assessments and substituted judgments, and to identify qualities of the patients and their caregivers that are associated with these QOL assessments. DESIGN: Cross-sectional interviews. SETTING: A university-based Memory Disorders Clinic. PARTICIPANTS: Forty primary caregivers of AD patients. MEASUREMENTS: Direct scaling of overall quality of life (poor, fair, good, very good, or excellent) and measures of dementia severity, the caregiving experience, and patient and caregiver demographics. RESULTS: The majority of patients had mild (n = 20) or moderate (n = 11) AD. Caregivers' direct assessments of patient QOL were poor (5%, n = 2), fair (28%, n = 11), good (40%, n = 16), very good (20%, n = 8), and excellent (8%, n = 3). Twenty-one (52.5%) of the caregivers rated the patient's QOL the same as they thought the patient would; 12 (30.0%) rated the patient's QOL worse; and seven (17.5%) rated the patient's QOL better. Agreement between the two ratings was fair to moderate. Bivariate analyses showed that lower ratings of caregivers' direct assessments of patient QOL were associated with decreasing ratings of patient mental health and increasing dementia severity, caregiver burden, and caregiver depression. Multivariate models showed burden to be the significant predictor of caregivers' rating of patient QOL and the subscale measuring the caregivers' distress at controlling patient behavior had the strongest association with QOL. Lower ratings of substituted judgment assessments of patient QOL were associated with lower caregiver ratings of the patient's mental health. CONCLUSIONS: Nearly one-half of the caregivers of patients with predominantly mild to moderate AD assess a patient's QOL differently than they believe the patient would. Dementia severity and the caregiver's experiences of depression and burden negatively affect caregivers' assessments of QOL. These results provide a compelling reason why clinicians should take the time to screen for and address caregiver depression and burden and problematic patient behaviors.