Future role of quality-of-life assessment in outcomes research

Historians will confirm that the upsurge of interest in quality-of-life research during the last 30–40 years has been a major impetus to current pharmacoeconomic outcomes research, especially when applied to the medically ill. More recently, the concept and assessment of quality of life has been subsumed under the label of patient-reported outcomes (PROs), with PROs including symptoms and other health status indicators. As an early witness to the establishment of the PRO concept, I can say that its development represented an effort to overcome the resistance of the US FDA to accept the patient’s voice as a determinant in the selection of a drug or device. The compromise was to shift away from measuring quality indicators to measuring whatever indicators reflected the status of the person. This broadening permitted the inclusion of a variety of more biologically oriented indicators, along with various subjective qualitative indicators. However, as an outcome of this process, the importance of quality assessment in the development and selection of drugs and devices has been significantly diminished. This creates the risk that new drugs or devices will be approved without an adequate patient-based adverse-effect profile; a risk that I would argue borders on being unethical. The primary reason for performing a qualitative assessment is to ensure the ethical character of any innovation. This can be achieved in a variety of ways, including providing an adverse-effects profile for a drug or device.

The purpose of this editorial is to discuss one small aspect of why the assessment of quality of life has engendered resistance as an acceptable outcome indicator. The issue, I am suggesting, is associated with massive confusion regarding the definition of the phrase ‘quality of life’ and, in particular, the failure of investigators to acknowledge that a quality-of-life assessment is, first and foremost, a quality indicator. Therefore, quality of life has formal similarities to other quality indicators, whether involving the production of a car, evaluation of a meal, a painting or nursing home care [Barofsky, In preparation]. The specific confusion I would like to discuss is the suggestion by some investigators that the term ‘well-being’ is a quality indicator. In what way is this true and in what way is it not? By focusing on what might be described as a fairly arcane issue, I hope to sensitize various investigators to the importance of the precise use of language and, in particular, to examine the intellectual history that is connected to such important concepts as well-being.

First, one of the characteristics of quality or quality-of-life research is that it does not have a special scientific language (compare this with physics and, to a certain extent, biology, each of which has developed a special vocabulary to describe their concepts). Instead, quality of life is based on the language of everyday discourse. As a result, it is at constant risk of misuse because of patterns of common usage and methods of communication, but also because of differences that are created when a concept is translated into another language. This is particularly true when the term ‘well-being’ is used as a surrogate for ‘quality of life’. Occurrences of this substitution can be readily demonstrated by inspecting various definitions of quality of life. For example, Cella defines health-related quality of life as follows; “health-related quality of life refers to the extent to which one’s usual or expected physical, emotional, and social well-being are affected by a medical condition or its treatment” [1]. Similar definitions are provided by Ebrahim [2], Felce and Perry [3], Ferrans [4], Goty et al.[5] and Padilla et al.[6].

The simplest way to proceed is probably to examine some of the ways that the terms, ‘quality’ and ‘well-being’ are commonly used in our language. It is evident that ‘well-being’ refers to feelings a person may have that may or may not be associated with a specific event or object. While ‘well-being’ refers to feelings, it is not what is ordinarily meant by emotion (which is usually thought of as a short self-limiting feeling), nor is it a mood (which can be changed with a drug). Thus, there are no well-being drugs on the market, as far as I know, but there are plenty of mood-altering drugs (e.g., anti-anxiety or antidepression drugs). In contrast, the term ‘quality’ is much more likely to be associated with an object (e.g., ‘that was a good meal’ or ‘that person had a good life’). In addition, it is not clear that we are always aware of our feelings of well-being; it is as if a threshold must be reached. By contrast, a quality assessment can be applied at all levels of our experience. In addition, while the term ‘well-being’ usually refers to a positive state that a person is in, a quality indicator can reflect both positive and negative states. Consistent with these distinctions is the Oxford English dictionary definition of well-being as “a state that a person is in” (e.g., the state of being comfortable, healthy or happy), while the term ‘quality’ is defined as ‘an evaluation’ [7].

Thus, the term ‘well-being’ is not an evaluative statement per se, it is a descriptive statement that can assume an evaluative role by the connotation created by a grammatical form (e.g., asking the question, ‘How good is your well-being?’), its use as a metaphor and so on. Well-being can also assume a role as a quality indicator if the respondent engages in the metacognitive process of reflecting about the importance or impact their evaluation has on their well-being state. I refer to this reflection as a ‘qualification’ process. Therefore, new meanings or roles for a term can be created, and this suggests that multiple cognitive processes are combined to form a ‘hybrid cognitive construct’. The elements of this construct are description, evaluation and qualification [Barofsky, in preparation]. A good example of a synthetic hybrid cognitive construct is the quality of well-being scale developed by Bush and Kaplan [8]. This assessment conflates various personal descriptors with a weighting system that reflects the perceptions of a representative sample of the general population.

To define quality of life as well-being, as Cella and others do, is tantamount to declaring that a quality indicator is a feeling [1]. However, it should be obvious that, while a quality indicator may reflect a person’s feeling, a quality indicator may have other meanings that are lost in these definitions. Part of the reason why it appeared reasonable to these authors to define quality of life as a form of well-being is that the WHO definition of health also included reference to a person’s well-being. However, this association has been found to be conceptually and practically inappropriate for defining health and should be for defining quality or quality of life [9].

If a quality indicator is not exclusively a feeling, what is it? First, I would not deny that emotions play some role in defining quality, just that in some quality settings this role could be quite minimal. For example, in judging the quality of a golf course, there may be an element of aesthetics involved that will reflect an emotional input, but much of the judgment would revolve around how well the course functioned as a place where a crowd of people participate in a game. The same could be said about judging the quality of a product, a painting or a life. In each case, there is both an aesthetic and functional component to any estimate of quality, although the role of each will vary depending on the context.

What then does this argument say about the future of quality-of-life assessment in the development of pharmaceuticals? First, investigators who are interested in performing a qualitative assessment must learn and respect the intellectual foundation upon which the field is based. This may require excursions into areas such as philosophy, sociology and the neurosciences. Second, quality-of-life research should be seen as one of a broader set of principles that combine to form a quality assessment. Third, although it is tempting to define quality of life in terms of a feeling, to do so limits the value of a qualitative assessment to purely subjective responses, whereas focusing on the functional aspect of a qualitative assessment adds another, possibly more measurable, dimension.

In the future, the development of new drugs, from Phase I onward, should involve both an aesthetic and functional qualitative assessment. This is a necessary, although not sufficient, action required to ensure that the process of developing a new drug or device, as well as the resultant products themselves, comply with our professional and universal mantra of doing no harm.

Financial & competing interests disclosure

The author has no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.