Definitions of quality of life: what has happened and how to move on

Quality of life (QOL) is an important outcome in spinal cord injury (SCI) rehabilitation, but it is unclear how to define and measure it.

The aims of this article are to (a) show how the concepts of QOL and health-related quality of life (HRQOL) have evolved over time, (b) describe the various ways QOL has been defined and measured, and (c) provide recommendations on how to be as clear and consistent as possible in QOL research.

A narrative review of the QOL literature was performed.

Roots of the term "quality of life" in health care can be traced back to the definition of health by the World Health Organization in 1948. The use of the word "well-being" in this definition is probably a main factor in the continuing confusion about the conceptualization of QOL. Within the field of SCI rehabilitation, the Dijkers's QOL model, distinguishing between utilities, achievements, and subjective evaluations and reactions, has been very influential and the basis for several reviews and databases. Nevertheless, literature shows that it is still difficult to consistently use the term "quality of life" and categorize QOL measures. Several aspects of QOL that are specific for individuals with SCI have been identified.

Researchers should be as specific and clear as possible about the concept and operationalization of QOL in their studies. Readers should not take the term "quality of life" for granted, but should inspect the topic of the study from the actual measures used.