How do Chinese patients with dementia rate their own quality of life?

Abstract

This study examines the psychometric properties and clinical experience in using the Mandarin translation of the Quality of Life-Alzheimer's Disease (QoL-AD) instrument in Chinese patients with dementia in Singapore. A Mandarin version of QoL-AD was established following standard guidelines for transcultural adaptation of QoL measures. The instrument was administered to 70 patient-carer dyads; patients with severe dementia (MMSE < 10) were excluded. Reliability by internal consistency and test-retest, and construct validity by correlating the known domains of QoL-AD with validity measures for the respective domains, was performed. Guidelines for Rating Awareness Deficits (GRAD) measured patients' insight into their deficits. Three patients were not able to complete the QoL-AD. Internal consistency (Cronbach's alpha) was high for both patient (0.9) and carer (0.8) QoL-AD ratings, as was test-retest reliability, intraclass correlation coefficient (ICC) 0.7 and 0.8 respectively. Correlation of QoL-AD with domain measures was moderate for carer ratings (0.21 < r < 0.51) and poor for patient (-0.17 < r < 0.13). Patient self-rated QoL correlated poorly with, and was significantly higher than, carer-rated QoL. Correlation between patient and carer QoL-AD was stronger in patients with better insight (GRAD 3-4). The results suggest that while the Mandarin version of QoL-AD can be used reliably in our population, patients' self perceived QoL can be different from carer ratings and from objective QoL measures. The disparity can be attributed to patients' poor insight, denial, fear of "losing face," normalization and accommodation of standards with aging. The patients' lack of education and seclusion from Western cultural exposure are also contributory.