What do we know about quality of life in dementia? A review of the emerging evidence on the predictive and explanatory value of disease specific measures of health related quality of life in people with dementia.

OBJECTIVE: Given its complexity, there is growing consensus on the need to measure patient-rated broad outcomes like health-related quality of life (HRQL) as well as discrete functions like cognition and behaviour in dementia. This review brings together current data on the distribution, determinants and course of HRQL in dementia to investigate the predictive and explanatory value of measures of HRQL in people with dementia.
DESIGN: A systematic review of papers in English published up to October 2007 to identify data on the use of disease-specific measures of HRQL in dementia.
RESULTS: There are no clear or consistent associations between socio-demographic variables and HRQL. There is no convincing evidence that lower cognition or greater activity limitation is associated with lower HRQL. There is a strong suggestion that depression is consistently associated with decreased HRQL in dementia. However, the magnitude of the associations observed is moderate only and the proportion of variance explained is low suggesting that depression and HRQL are different constructs. We currently know almost nothing about the natural history of HRQL in dementia or what attributes or interventions promote or inhibit HRQL life for people with dementia.
CONCLUSIONS: While in other illnesses there may be simple association between HRQL and an easily measurable clinical variable, in dementia this is not so. There are now instruments available with which to measure disease-specific HRQL directly in clinical trials and other studies that can yield informative data. (c) 2008 John Wiley & Sons, Ltd.