Reflections on the usefulness of the term ‘health‐related quality of life’

Focusing on measures of health outcomes in young people with Duchenne muscular dystrophy, Wei et al. observed that the terms ‘quality of life’ (QOL) and ‘health-related quality of life’ (HRQOL) are frequently used interchangeably, despite being different constructs. They stated that HRQOL limits the extent of QOL, focusing primarily on the impact of illness and different treatments on a person’s life. Their conclusions were that although QOL and HRQOL were closely related, they are essentially different concepts and that there are factors beyond health that help to make up overall QOL. It must be noted, however, that there are numerous interpretations of HRQOL that differ significantly in their content, resulting in no single concept being universally accepted. A brief historical review illustrates why HRQOL means different things to different people. The first time the term HRQOL was used in a title, Torrance (1987) conceptualized HRQOL as containing only physical and emotional functioning (functions in today’s ICF terminology), omitting social functioning, which he considered outside the scope of health. In contrast, Wilson and Cleary (1995) proposed a comprehensive conceptual model of HRQOL that integrated both biomedical and psychosocial aspects of patients’ outcomes with a pathway from physiological variables to symptom status, to functional status, to general health perceptions and to overall QOL. This model was later validated using structural equation modeling. Spilker and Revicki (1996) specified that HRQOL conceptually include the domains of physical, psychological, social, spiritual, and role functioning as well as general well-being. When using the term ‘health-related’, researchers should conceptualize, operationalize, or define health within the context of the measures they develop or use. In 1948, the United Nations declared in the Constitution of the World Health Organization that ‘Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity’. This concept goes far beyond the biomedical parameter to include dimensions of mental and social well-being. The International Classification of Functioning, Disability and Health views health as a dynamic process among the interconnected categories of functioning (body structure and function, activities, and participation) and environmental and personal contextual factors. Subsequently, Huber et al. discussed the challenges of continuous changes in population and health condition demographics. They proposed to reframe health both broadly and positively as ‘ . the ability to adapt and to self-manage, in the face of social, physical and emotional challenges. ’ Those authors proposed to move away from static definitions with clear boundaries that try to present a precise meaning, to an open concept that would give a generally agreed direction, with measurable dynamic features and dimensions. Huber et al.’s novel concept would allow people with impairments to consider themselves healthy. We observe here the evolving conceptual process of theoretical constructs (health and HRQOL) that reflect continuously acquired evidence and experience. In the last decade, the US Food and Drug Administration and others strove to develop terminology upon which healthcare providers, researchers, and policy makers could agree. They proposed moving away from the unsettling bewilderment and barriers to communication created by the different definitions, and to avoid the use of HRQOL and related concepts altogether. Their recommendations were to focus on the source of information, particularly the perceptions coming directly from patients, and to use the currently preferred terms: patient-reported outcomes and patient-reported outcome measures. Irrespective of the chosen terms, people should evaluate the content and wording of the items in outcome measures, and how these were selected, before deciding whether a specific measure fits their research question, concept, population, goals, and ethics. One-item questionnaires raise reservations about their content validity and are better avoided. Researchers should express their results in effect-size and confidenceintervals to avoid unduly reliance on p-values alone.