JRSM >
Volume 95, Number 10 >
Pp. 481-488
Institute of Theoretical Surgery, Philipps-University Marburg, Baldingerstrasse, D-35033 Marburg, Germany
Correspondence to: Michael Koller E-mail: koller{at}mailer.uni-marburg.de
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 TOP INTRODUCTION THREE-COMPONENT OUTCOME MODELTHE CORRELATES OF QUALITY...CAUSALITYAN EMPIRICAL DEFINITION OF...QUALITY OF LIFE PROFILE...CONCLUSIONSREFERENCES |
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‘Scientists may use rating scales and visual analogue scales to measure pain, and they may even invent scoring systems quantifying types of handicaps; but when they talk about measuring quality of life they have gone too far’4.
This statement reflects a two-world model of medicine and of human experience in which objective facts are clearly distinguished from subjective values4,5. It can be seen as a reaction to the World Health Organization's concept of health and of quality of life that invites us to mix facts and values non-systematically:
‘Quality of life is defined as an individual's perception of their position in life in the context of the culture and value system in which they live and in relation to their goals, expectations and standards and concerns. It is a broad ranging concept affected in a complex way by the person's physical health, psychological state, level of independence, social relationships, and their relationship to salient features of their environment’6.
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Our approach to quality of life is based on the principles of experimental social psychology. This relatively new life science proceeds by hypothesis testing. As West and Wicklund8 put it, ‘Theories will ultimately be evaluated on their ability to account for the results of existing research, to suggest ideas that can be tested in future research, and to predict correctly outcome of research’9.
| THE CORRELATES OF QUALITY OF LIFE |
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Symptom distress
Overall, somatic symptom distress was highly correlated with the
psychological variables negative affect (r=0.70 to r=0.75),
experienced social stigma (r=0.51), social desirability
(r=-0.50) and positive thinking (r=0.40 or r=-0.40,
depending on whether positive affect or compensatory self-related positive
thinking was
dominant)11,12,13.
These psychological variables deserve explanation. Negative affect (NA) is defined as a summary category of unpleasant emotional states such as anxiety, restlessness, depression or low self-esteem. Individuals scoring high on NA scales have the propensity to experience such unfavourable emotions. This variable is considered of central importance because of its consistent and strong relations to health complaints across a variety of studies, in different samples and with different NA measures14,15. Furthermore, there are also national differences in the level of NA16. These differences have to be taken into account when cross-cultural variations in standardized quality of life scores are under scrutiny17. NA is also a component of the EORTC questionnaire (items 21-24). Many users are unaware of this, since the questionnaire-developers chose for unknown reasons to label this set of items ‘emotional functioning’.
Social stigma is an individual's feeling that others treat him/her as a sick person and no longer as a normal member of society. Experienced social stigma can be measured reliably with a 8-item scale11.
Social desirability is defined as readiness to endorse questionnaire statements that are valued by society. Since health is something highly valued in western society, individuals high in social desirability are expected to report few symptoms and high quality of life. Various measures to assess social desirability have been published12.
Finally, self-related thinking is an individual's proneness to introspection. Preoccupation with positive aspects of the self has been interpreted as a reaction to failure experiences18; and, since long illness episodes can be regarded as failure experiences, self-related thinking is relevant to the reporting of health complaints and quality of life19.
The correlation coefficients reported above characterize the association between somatic symptoms and psychological variables. A comparable pattern of results was observed when these variables were correlated with global quality of life as the quasi-dependent variable. However, both somatic symptoms and global quality of life were virtually unrelated to objective clinical criteria (tumour growth, findings of imaging techniques, carcinoembryonic antigen, external physicians' overall judgments)11,12,13. Clearly, quality of life is a domain outside the biochemical/molecular paradigm.
Expectations
Patients and their doctors were asked for their expectations regarding
radiotherapy20,21.
Both gave their responses before the start of therapy, and it turned out that
patients showed a much richer spectrum of expectations than doctors, who
focused on pain relief and tumour size reduction. The most dramatic difference
was in expectations of cure. 58% of the patients expected cure from
radiotherapy, whereas from the doctors' standpoint this was a realistic
expectation in only 7%. In fact, most patients were receiving palliative
therapy for advanced cancer. Although the patients were carefully informed,
many of them expected to regain their health. In the published work,
psychological processes of this sort are labelled ‘positive
illusions’22
and
‘denial’23.
A remarkable observation was that those who expected healing had a
significantly better quality of life (or those who expected only pain relief
had a significantly worse quality of
life)21. For
clinical purposes, we need to know the individual patient's expectations.
Priorities
Therapy priorities have been investigated in relation to
cholecystectomy24.
When patients were asked in a qualitative analysis which endpoints they ranked
most important for outcome we were surprised by some of the answers. A rapid
return to physical fitness—becoming the same as before the
disease—was sometimes rated higher than death and more important than
pain, hospital stay and cosmesis. Yet in the more than sixty studies comparing
laparoscopic with conventional cholecystectomy, return to physical fitness has
never been the primary endpoint. Though otherwise well designed, these studies
seem to have assessed outcomes that were of more interest to doctors than to
patients.
| CAUSALITY |
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The philosophy of science offers numerous definitions and concepts of causality, and that of Collingwood is particularly appropriate for the present discussion35. According to Collingwood, a cause is something that can be altered in order to instigate a desired change in a given environment. From this perspective, if a specific precondition (e.g. gene defect) of cancer has been detected that can not be altered by humans, this is not regarded as a cause. The quest for a cause continues until cancer can be successfully treated. Quality of life is an abstract term and there is no accepted way to enhance the quality as such. However, more concrete aspects such as expectations, negative affect, social stigma or patient preferences can be foci for intervention. Patients' expectations should be modifiable through careful information36,37, their negative affect through psychotherapeutic interventions38,39,40, and social stigmatization by influencing the family environment11 or bringing patients' preferences into harmony with medical decision-making41. These settings also would allow for testing of specific unidirectional hypotheses within randomized controlled therapeutic trials. Furthermore, the correlational studies enhance our understanding of patients' responses to standard quality-of-life questionnaires. Such questionnaires produce results that are hard to interpret without additional information. ‘Naked’ quality-of-life-scores yield no real understanding of the patient's personal experiences. One has to know the network of variables in which the assessments are embedded.
| AN EMPIRICAL DEFINITION OF QUALITY OF LIFE |
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| Box 1 Our concept of quality of life Assessed in disease—the critical model Self-perception and self-report in 3 domains: somatic, psychological, social Includes health-related and therapy-related expectations and coping Is influenced by psychosocial variables such as negative affect Is part of a three-component outcome model including mechanistic endpoints, hermeneutic endpoints and a qualitative analysis of clinical relevance
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Health-related or disease related?
When assessed in patients, quality of life is not related to
health (as is commonly argued in textbooks and
journals)42, but is
rather related to disease, and in particular to a specific
disease6. The
critical model of disease is defined by a combination of the biological model
of disease and the psychosocial model in which the patient suffers and seeks
help from the
doctor7,43.
This viewpoint is very different from the ‘having fun’ stereotype
of a good quality of life. Current quality of life questionnaires have been
developed for and validated with ill people. The psychological predicament and
consequently the concept of quality of life of ill people may differ from that
of ‘healthy’ or ‘normal’ people. Specifically,
patients have something socially and personally undesirable, namely an
illness; they want to get rid of this condition, to get from one state to
another; patients' physiological abnormal state (with raised levels of
cytokines etc.) may affect the psychological state and thus questionnaire
responses; notions such as palliation are outside everyday human experience,
so special assessment instruments are
necessary44,45.
Self-reported or physician-assessed?
‘Self-reported’ means that quality of life is not assessed by
the doctor but via a questionnaire used under the patient's control. It does
not simply consist of a statement of symptoms such as pain yes or no, but also
provides an evaluation such as severe or intolerable. Three groups of
dimensions (domains) are included—somatic symptoms such as pain;
psychological components including emotion, cognition and general
consciousness; and social components such as family, work and sexual
satisfaction.
Judgments of overall wellbeing or coping
Several questionnaires (EORTC, SF36) ask for a person's overall judgment of
quality of
life.46,47
This judgment must not be confused with the aggregation of a summary score
across different quality-of-life components, as preferred by other
questionnaire
designers48,49.
At individual patient level, clinical experience teaches that some patients
rate their overall quality of life as quite good when they are clearly very
ill. We give an example later. In aggregate patient samples, regression
analyses show that objective health variables and self-reported health
variables do not fully explain the variance of global quality of
life11,12.
A famous example is the work of Brickman et al. showing that, after
an adaptation period of one year, paraplegic accident victims and lottery
winners reported practically the same level of overall
wellbeing50—a
phenomenon known as the wellbeing
paradox51.
Seemingly, an overall judgment of quality of life includes a component of
coping52.
| QUALITY OF LIFE PROFILE AS A TOOL FOR INDIVIDUAL PATIENT CARE |
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For two reasons, a score value of 50 can be regarded as the threshold level for intervention. First, the EORTC QL questionnaire items tap into patients' degree of impairment and answers can be given on response scales of 1-4 (1=not at all, 4=very much so). Responses can be easily dichotomized with 3 and 4 the ‘bad’ side and 1 and 2 the ‘good’ side62. Second, according to psychological theories on adaptation level and social comparison, persons generally try to perform slightly better than average63. Clearly, therefore, values under the average (50) are undesirable; the goal of therapy is to bring patients over 50. Note that, at least for global quality of life or overall happiness, a value of 100 is not necessarily desirable all the time. Highest levels of happiness also involve intense physiological arousal which may be burdensome and distracting if it lasts too long. Therefore, ‘good’ or desirable overall quality of life is usually between 60 and 80 points on a 0-100 scale51.
Although a threshold level of 50 seems reasonable, it is clearly not an immutable law. Clinical research may tell us that a focus on extreme levels is more useful. Furthermore, the threshold must also take into account cultural and individual differences16,64. In medicine, the norm can change, as illustrated recently in hypertension65. Until this issue of the threshold is settled by research, we shall use the 50-point score as a starting point.
Two patients
Let us illustrate how our concept of outcome and quality of life relates to
individual patients and their treatment. Two patients, A and B, were enrolled
in a randomized study of G-CSF prophylaxis in patients undergoing operation
for colorectal
cancer66. Quality
of life was assessed pre-operatively, at discharge and, at months two and six
postoperatively. The last assessment included an in-depth standardized
interview in which the patient was invited to report on the most important
aspects of the illness episode.
In terms of objective health status these two patients were very different (Box 2). Patient A had a T1 tumour of the rectum, giving him a 5-year survival chance of 90%. His postoperative complications included focal anastomosis leakage and neurologically disturbed micturition until six months postoperatively. Patient B had a T4 tumour (5-year survival chance 50%). Furthermore, postoperative complications included not only disturbed micturition but also a cerebral infarction. Let us now turn to global quality of life (Figure 2). For the entire period patient B, more severely ill, displayed higher global quality of life than patient A. This is particularly evident in the area under the curve (Figure 3). These results are striking because they do not follow the lead of the individual score points. Interestingly, patient A displays no < 50 values. In contrast patient B, despite numerous lower scores, particularly in role and cognitive functioning, has an acceptable overall quality of life throughout the follow-up.
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As a next step background information (basic psychological variables, medical record, interview with patient) has to be inspected. Patient A expected healing from therapy; that is a positive sign and should have helped in recovery. The interview at six months revealed why his recovery had been relatively slow. He explained that the stoma had been the most important therapy-related problem. Although it functioned, it was psychologically a big shock (it was removed four months postoperatively). When asked about his best experience, he mentioned his leisure time, although he had too much. When asked what was the most important event, he named nothing specific except that he was still alive. Furthermore, he said that there were no important changes in his life. It is very striking that this patient never mentioned his family or friends. All in all, he gave the impression of a rather empty life.
Patient B also had expectations of cure, and at the onset of therapy had a lower degree of negative affect than patient A. This may partly explain why his overall quality of life was better despite postoperative troubles including a stroke. At the six-months interview he said that his worst experience had been the diagnosis and his best had been getting back to his family. His medical condition was preventing him from fulfilling previous social commitments, but his family and friends were supportive and he was getting lots of visits. Thus, unlike patient A, this patient had a very active social and family life.
Consequences for individual care and regional health care
These examples show that quality-of-life profiles can be read like an
electrocardiogram or any other functional test. The profile does not replace
the conversation between doctor and patient. On the contrary it may stimulate
useful discussion—as in patient A, where the interview disclosed reasons
for his poor recovery. We would advise such a patient to take up social
activities or a hobby that make better use of his leisure time. Patient B
might benefit from physical therapy and advanced stoma therapy; he has to be
persuaded that the stoma does not preclude social activities.
Our experience with quality-of-life assessment in patients is promising. Patients accept this endpoint and are happy to be asked about matters that ‘really count’ for them. Doctors, too, are beginning to accept quality of life as an endpoint and a diagnostic tool. In an implementation study, quality-of-life profiles have been routinely sent to the doctors in charge of follow-up treatment of cancer patients. Through various implementation strategies (academic detailing, outreach visits, continuing medical education) doctors have been taught that 50 points is the level for intervention and lower values may indicate a clinically relevant deficit. All the doctors found the profile easy to understand, and more than half said it led to more information and better communication67.
On the basis of our experience with quality-of-life assessment, we restructured follow-up care for cancer patients in our region67,68. A list of treatment options that appear beneficial for improving quality of life and that are available in the region has been compiled69. The major domains of intervention doctors can choose from and that can be evaluated by follow-up quality of life assessments are:
Furthermore, guidelines now include quality of life as an essential endpoint for care68,70,71.
| CONCLUSIONS |
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TOPINTRODUCTIONTHREE-COMPONENT OUTCOME MODELTHE CORRELATES OF QUALITY...CAUSALITYAN EMPIRICAL DEFINITION OF...QUALITY OF LIFE PROFILE...CONCLUSIONSREFERENCES |
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Acceptance of the quality-of-life concept within the medical community will depend on its contributions to better understanding of patients and of treatment effects. Thus, we propose a profile format that clinicians readily understand, in which deficits in particular domains are easily recognized. The reasons why a particular deficit exists, however, is not always evident from the profile. The patient has to explain75. In other words, a quality-of-life profile is not a substitute but a starting-point for a patient—doctor interaction. The interaction can be structured and efficient, and the benefit of any action taken can then be assessed by a further profile. There is no contradiction between this empirical approach, and doing something ‘humanistic’ for the patient.
| Acknowledgments |
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| REFERENCES |
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TOPINTRODUCTIONTHREE-COMPONENT OUTCOME MODELTHE CORRELATES OF QUALITY...CAUSALITYAN EMPIRICAL DEFINITION OF...QUALITY OF LIFE PROFILE...CONCLUSIONSREFERENCES |
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