What’s wrong with quality-of-life measures? A philosophical reflection and insights from neuroimaging

Abstract

The authors propose a reflection on quality of life (QoL) measures in medicine following the work of G. Canguilhem on health and disease and the latest results from neuroimaging. The use of QoL measures implies that the tension between the two competing visions of health (i.e., normative and descriptive) needs to be overcome. A profound cultural change is needed if we want clinicians, researchers and decision makers to suspend their prevailing scientific ideologies about disease and examine the content of the patient’s experience. Another issue that concerns the direction of future QoL is that until now, the available measurements and recent work were ambiguous, trying to find a commonly acceptable, intermediate position halfway between these normative and descriptive visions. It may be time to discard the medical normative vision and instead assume a radically humanistic approach to medicine by providing purely descriptive measures based on the values and emotions of patients.

Keywords::

• disease
• emotion
• functioning
• health
• quality of life

The moment is ripe to think about how quality-of-life (QoL) measures could be improved. QoL measures have been of growing interest to the scientific community for more than 20 years. The US FDA and the EMA encourage the use of QoL assessments in medical product development for patients with chronic illnesses, and several groups have published detailed recommendations for QoL assessment [1,2]. Despite the acknowledged need to consider QoL issues, QoL assessment remains under- or misused by clinicians, researchers and decision makers [3,4]. Many barriers have been identified by QoL researchers to explain this phenomenon and these barriers have been the subject of numerous scientific studies [3,5–10]. All of this work has led to a high level of performance for QoL measures, likely higher than with most traditional tools currently used by clinicians [11]. Nevertheless, these advances have not been accompanied by a greater conviction of potential users about the relevance of QoL measures. This phenomenon can be explained by certain conceptual problems. The authors propose reflection on this issue.

QoL is often defined as the way that individual patients feel about their health status and/or the nonmedical aspects of their lives [8]. This definition is part of a broader movement in which the patient’s perspective is considered to be as valid as that of the clinician in regard to evaluating health outcomes [12]. While previous medical thinking laid emphasis on the disease and focused on the clinician’s appraisal of health status, a more recent line of thought emphasizes the subjective experience of individuals. Although entirely valid, this conception has the disadvantage of underestimating the problem of QoL by simply placing the physician’s objective view in opposition to the patient’s subjective view. From this perspective, the main problem to resolve is to convince clinicians, researchers and decision makers that subjective measures are as valid and useful as objective measures. However, it is unlikely that new scientific work, recommendations and guidelines to use QoL measures will be sufficient to convince them because the problem is likely deeper and upstream of this dualism, which is only one effect. G. Canguilhem’s work on the history of medicine can help us understand this problem [13]. As clearly explained by R. Horton [14], G. Canguilhem saw medicine as a continual conflict between normative (the interpretation of evidence according to a set of scientific values) and descriptive (the act of producing evidence free of values) forces. On the one hand, pathology or disease is considered as an excess or deficit of a particular variable. Healing will then consist of returning to the ‘norm’ defined by limits derived from population data. On the other hand, Canguilhem proposed another definition, in which health is considered as the ability of an individual to adapt to challenges posed by the environment and to create new norms for new settings. Here, normality is measured by the adaptability of the individual. In our opinion, QoL is defined by this second approach. The tension between these two conceptions of health may more deeply explain the underuse of QoL measures. Indeed, the use of QoL measures implies that clinicians choose a purely descriptive method of health based on the values of their patients and thus suspend their prevailing scientific norms (or ideologies) about health and disease. This change requires a far more fundamental transformation than what is achieved by current actions (e.g., guidelines and recommendations and the QoL studies described above). Several measures could be proposed to improve the use of QoL assessment. On the one hand, the challenge is to propose a pedagogy of health and disease to professionals, that is, to teach them to recognize, understand and respect the singularity of each patient. In addition, a range of culture change models has been developed for health care [15] and should be applied to the QoL domain. On the other hand, the use of QoL measures in health care also implies more ambitious programs of dissemination and implementation, with adequate technical and financial support [16], based on incentive programs proposed by government agencies and health organizations, as in other health domains (e.g., the implementation of quality programs in health care organizations and the adoption of clinical information technology).

Now, considering the theoretical basis proposed by Canguilhem, another question is whether available QoL measures completely fit this descriptive vision of medicine and health. The authors do not believe that QoL research thoroughly considers the implications of this vision.

Certain researchers believe that QoL mainly depends on people’s objective life conditions (i.e., health status and functional impairment, education, food, clothing, housing, entertainment, number of friends and adequacy of financial resources). This approach is called ‘objective QoL.’ An important assumption underlying this approach is that objective life conditions are the means necessary to have good QoL. However, it is not certain that better objective life conditions systematically lead to better QoL. The assumption that QoL emphasizes the means ignores several important components, including particular differences between individuals’ abilities to transform the means into well-being. Here, we find a normative approach based on medical and social norms, and not a purely descriptive approach.

Other researchers have tried to go beyond this vision and have defined QoL as a life evaluation, that is, the degree to which people view themselves as being satisfied with or achieving important possibilities in their life [17], following the definition provided by WHO. This approach is also called ‘subjective QoL.’ From this perspective, the self-perceived functioning of patients is a key component of QoL instruments because physical, psychological/emotional and social functioning are considered as the required conditions for ‘enjoying the important possibilities of life’ and thus for achieving well-being. The majority of recent subjective QoL questionnaires mainly refer to life evaluation. Although based on self-assessment, this approach is still normative, associating QoL with a level of functioning to achieve.

Interestingly, certain authors have suggested that subjective QoL not only should be reduced to life evaluation but also should include the feelings of patients, such as positive and negative emotions [18,19]. A recent study reported that emotional well-being (i.e., the frequency and intensity of positive emotions such as joy and pride and of negative emotions such as pain and worry that make one’s life pleasant or unpleasant, respectively) and life evaluation were not highly linked [20]. In this study, high income was associated with better life evaluation (i.e., better self-perceived functioning) for individuals, but not with better emotional well-being. Interestingly, this emotional construct of subjective QoL is supported by recent neuroimaging studies, which have suggested that QoL is closely linked to the neural brain network regulating emotional behavior. One study showed that in fibromyalgia, QoL was associated with right medial temporal metabolism within the limbic system, which is involved in the affective and emotional domains [21]. Another study found that another brain area, the superior temporal sulcus, contributes to self-/other awareness, metacognition (i.e., the ability to attribute mental states, in terms of beliefs and goals, to oneself and others) and a range of social cognitive abilities in schizophrenia [22]. Metacognition plays a central role in the understanding, learning and regulation of emotions. Taken together, these neuroimaging findings suggest that QoL is influenced by the emotional experiences of individuals, which are associated with their metacognitive abilities. In accordance with these findings, it has been shown that striatal dopamine depletion can lead to negative subjective states that frequently affect QoL, especially a person’s ability to experience pleasure [23]. The mesolimbic dopamine system has also been associated with anhedonia, reduced motivation and decreased energy levels in depression [24], which is one of the most important determinants of QoL.

While the two previous QoL approaches were based on the conditions of well-being, an emotional approach seems to be more direct. This approach does not consider the conditions of well-being (i.e., objective conditions and self-perceived functioning) because these conditions vary between individuals and thus reintroduce a normative approach. As proposed by certain philosophers, we are always missing something about the causes of well-being. As written by Blaise Pascal, ‘the weather and my mood have little connection. I have my foggy and my fine days within me; my prosperity or misfortune has little to do with the matter’ [25]. Taking this emotional dimension into account in QoL measures may provide important information, which is more oriented toward patients’ feelings and values, to clinicians. Recent works in neurology have begun to incorporate self-reported measures of emotion in QoL instruments [26]. Other works have also proposed to study emotion of patients through the analysis of their speech, using language-based methodologies.

In conclusion, the use of QoL measures implies that the tension between the two competing visions of health (i.e., normative and descriptive) needs to be overcome. A profound cultural change is needed if we want clinicians, researchers and decision makers to suspend their prevailing scientific ideologies about disease and examine the content of the patient’s experience. Another issue that concerns the direction of future QoL is that until now, the available measurements and recent work were ambiguous, trying to find a commonly acceptable, intermediate position halfway between these normative and descriptive visions. It may be time to discard the medical normative vision and instead assume a radically humanistic approach to medicine by providing purely descriptive measures based on the values of patients.

Financial & competing interests disclosure

The authors have 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.