Measuring the quality of later life.

This paper examines quality of life as a scientific construct with a wide range of applications. The assessment of patients' quality of life is assuming increasing importance in medicine and health care. Illnesses, diseases and their treatments can have significant impacts on such areas of functioning as mobility, mood, life satisfaction, sexuality, cognition and ability to fulfil occupational, social and family roles. The emerging quality of life construct may be viewed as a paradigm shift in outcome measurement since it shifts the focus of attention from symptoms to functioning. This holistic approach more clearly establishes the patient as the centre of attention and subsumes many of the traditional measures of outcome. Quality of life assessment is particularly relevant to ageing populations both for healthy elderly and for those who develop chronic diseases where maintenance of quality of life rather than cure may be the primary goal of treatment. This paper introduces the concept of quality of life and describes the significant difficulties in definition, measurement and interpretation that must be addressed before such measures can be used as reliable and valid indicators of disease impact and treatment outcomes. It is argued that approaches to quality of life assessment in the elderly should incorporate advances in knowledge about the psychological adaptation to ageing. Consequently, the unique perspective of the individual on his or her own quality of life must be incorporated into outcome assessments aimed at improving the quality of health care. Incorporating measures of subjective outcome such as quality of life into policy decisions on resource allocation in health care will prove one of the major challenges for health services over the next decade.