Quality-of-life assessment in clinical trials

Health status, functional status, and health-related quality of life have become synonyms for QOL in the clinical trials literature.

Abstract

Within the context of clinical trials, quality of life (QOL) is a multidimensional concept that encompasses health-related constructs, but excludes other dimensions such as economics, housing, or education. Most QOL research has been based on the World Health Organization (WHO) definition of health [1]: 'Health is not only the absence of infirmity and disease but also a state of physical, mental and social well-being.' Thus QOL encompasses all health-related outcomes beyond those of survival and physiological responses. Diseases and their treatments affect not only patients' physical functioning and level of pain, but also their cognitive, emotional, and social functioning. QOL measures have also included assessments of sexual functioning, family and marital relationships, role performance, vitality, sleep, health perceptions, general life satisfaction, and symptoms such as nausea and fatigue. QOL assessment has been employed in developing individual patient treatment plans, performing cost-benefit analyses, making health policy decisions, and conducting clinical trial evaluations. Health status, functional status, and health-related quality of life have become synonyms for QOL in the clinical trials literature.