Agreement between patients' and proxies' reports of quality of life in Alzheimer's disease

Agreement between self reports and proxy reports of health-related quality of life (HRQoL) was examined in a sample of 76 patients with mild to modera te Alzheimer's disease and their proxies. Patients and proxies completed an (17-item Duke health profile). The items were rephrased for the proxy. The proportion of exact agreement between patients and proxies on the 17 items ranged from 26.3 to 52.6%. Results reveal poor to moderate agreement (intr aclass correlation coefficients (ICCs) from 0.00 to 0.61 for 10 subscales) between patients' and proxies' reports. Agreement was higher for measures o f function that are directly observable (physical health, disability) and r elatively poor for more subjective measures. Proxy reliability varied accor ding to the relationship of the proxy to the index subject. Spouses and nur ses agreed more closely with index subjects than did children or nurses' ai des. Agreement decreased with increasing severity of dementia. Statisticall y significant differences in mean scores were noted for several dimensions, with proxies tending to rate the patients as having a lower quality of lif e than the patients themselves. This study indicates the importance of cons idering the information source of a patient's HRQoL. However, assessments b y proxies should be used with caution.