Assessing quality of life of older people with dementia in long-term care: a comparison of two self-report measures.

AIMS AND OBJECTIVES This study sought to compare two well-known and well-used self-report quality of life questionnaires in terms of completion rates, reliability and assessment of quality of life. BACKGROUND People with dementia have a meaningful experience of quality of life and several disease-specific instruments have been designed to capture self-report assessments. DESIGN A quantitative survey design, with a convenience sample of older people with dementia from four long-term care facilities. METHOD Sixty-one participants were recruited for survey on the Dementia Quality of Life questionnaire and the Quality of Life in Alzheimer's Disease questionnaire. RESULTS The Quality of Life in Alzheimer's Disease questionnaire had a higher rate of completion (98·4%) than the Dementia Quality of Life questionnaire (68·9%). Those unable to complete the latter measure had significantly greater cognitive impairment (F(1,59) = 30·35, p < 0·001) than those completing the measure. Internal reliability was good for the Quality of Life in Alzheimer's Disease questionnaire (0·86), but there were varying levels found for the five Dementia Quality of Life questionnaire subscales (0·79-0·48). The Quality of Life in Alzheimer's Disease questionnaire was significantly correlated with all the Dementia Quality of Life questionnaire subscales and overall item. CONCLUSIONS Although it is recognised that there is no superior instrument in assessing quality of life, this study found both the Quality of Life in Alzheimer's Disease questionnaire and Dementia Quality of Life questionnaire to be useful self-report instruments. RELEVANCE TO CLINICAL PRACTICE Assessment of quality of life should include the perspective of the person with dementia. The Quality of Life in Alzheimer's Disease questionnaire and Dementia Quality of Life questionnaire appear to measure similar aspects of quality of life. Where assessments are sought from participants with more advanced cognitive and functional impairment, it may be favourable to employ the Quality of Life in Alzheimer's Disease questionnaire.