Quality Of Life Research Paper

2. Health-Related QoL

Because of the amorphous and multidimensional nature of QoL, most researchers in medicine and healthcare concern themselves with a subcomponent of QoL called health-related QoL (HRQoL). This is distinguished from QoL as a whole, which would also include adequacy of education, housing, income, and perceptions of the immediate environment. Health status and HRQoL measures increasingly are used in studies addressing the costs and benefits of services and treatments (Patrick and Erickson 1993). The US Congress established the Agency for Health Care Policy and Research to undertake research on the effectiveness of medical care in terms of its impact on patient outcomes including HRQoL. The US Food and Drug Administration encourages the collection of HRQoL data for new drugs and, in the UK, health status and the experiences of patients and carers are included explicitly in outcome assessments.

3. Definition Of Health-Related QoL

Patrick and Erickson (1993) defined HRQoL as:

the value assigned to the duration of life as modified by the social opportunities, perceptions, functional states and impairments that are influenced by disease, injuries, treatments or policy.

Assessment of HRQoL usually focuses on physical function, psychological state, social function, somatic symptoms, sexual function, occupational function, and, occasionally, on financial state. Many existing measures frequently are criticized for including only concepts at the negative or illness end of the continuum while neglecting concepts at the more positive end.

4. Assessment Of Health-Related QoL

There are a number of approaches to the assessment of HRQoL. Most of these involve some form of subjective multidimensional assessment preferably completed by the respondent whose QoL is under scrutiny since levels of agreement among doctors and between doctors’ and patients’ judgments are usually low (Sprangers and Aaranson 1992). Measures include generic instruments such as health profiles and utility measures, disease-specific questionnaires, and individually focused measures.

4.1 Generic Measures

Generic measures, such as the SF-36, The Nottingham Health Questionnaire, the McMaster Health Index Questionnaire, and The Sickness Impact Profile are broadly-based questionnaires and can be applied in a wide range of conditions and populations. The main limitation of generic questionnaires is that they are broad measures of health status. Consequently, they may not provide sufficient information on specific aspects of a given disease which are likely to be important in assessing disease impact and the outcome of treatment. It is common practice to use a generic measure together with a disease-specific measure. It is likely that the use of generic instruments will diminish as more sophisticated disease-specific measures are developed.

4.2 The World Health Organization QoL Instrument (WHOQOL)

The concept of HRQoL owes much to the original World Health Organization (WHO) definition of health as a state of complete physical, mental, and social well-being and not merely the absence of disease. The WHO established a multinational group to develop a measure that would allow for cross-cultural comparisons of QoL (WHOQOL 1993). The definition underlying the measure was:

QoL is defined as the individual’s perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns. It is a broad ranging concept affected in a complex way by a person’s physical health, psychological state, level of independence and their relationships to salient features of their environment.

The WHOQOL is a somewhat unusual measure of HRQoL because, in addition to measuring physical and psychological health and social relationships, it also measures spirituality and it deals with facets of the environment such as financial resources and home environment. In developing the WHOQOL, the authors unexpectedly found that the basic factors inherent in QoL did not differ substantially across cultures (Power et al. 1999).

4.3 Utility Measures

Utility measures are generic measures derived from economics and decision theory and represent patients’ preferences for different health states in the form of a single summary score. Their key characteristics are that they are based on preference judgments and usually are measured along a continuum from death (0.0) to perfect health (1.0), although scores less than 0 representing states worse than death are possible. Utility scores represent both health status and the value of that health status to the patient. They are used in cost-utility studies in which the cost of an intervention is related to the utility value afforded by the intervention. Various approaches to measuring utilities have been developed. In the Kaplan Index of Well-being Scale, case descriptions were compiled to illustrate combinations of functional levels, symptoms or problems and these cases were rated by random samples of the public who gave their preference ratings which were then used to determine utility values. In the somewhat controversial QALY (quality-adjusted life years) approach, improvements in the length and quality of life are amalgamated into a single index. In the standard-gamble approach, patients are asked to assess the risks they would tolerate for certain medical interventions. In the time-trade-off method, respondents are asked to estimate their relative preference for quality vs. quantity of life.

The utility approach assumes that individuals are capable of reporting their preferences and that they can predict accurately these preferences in relation to some future putative health scenario. It is further assumed that the preferences would not change if the patient were actually to experience such a health scenario. An additional problem relates to who should provide the utility values—the general public, healthcare providers, and/or patients and their families. One response to these problems has been the development of the Euroqol (Euroqol Group 1990). The aim of the Euroqol is to provide a standardized, nondisease specific survey instrument for describing HRQoL and to generate a single health index for each health state. The measure, however, suffers from a number of logistical and methodological limitations (Bowling 1995).

4.4 Disease-Specific Measures

The second approach to QoL assessment focuses on aspects of health status that are specific to the area of primary interest. It is assumed that responsiveness will be increased by including only important aspects of HRQoL that are relevant to the patients being studied. The measure may be specific to a disease (such as cancer or arthritis), to a population of patients (frail elderly), to a certain function (sexual function or sleep), or to a particular problem (such as pain). Specific measures focus on areas that are likely to be explored routinely by clinicians and are likely to be more responsive to small but clinically significant changes. The modular approach adopted by the European Organization for Research on Treatment of Cancer (EORTC) provides a core generic measure for use in a variety of cancers supplemented by diseasespecific modules for use in particular types of cancer.

4.5 Limitations Of Health-Related QoL

The restriction of QoL assessment to HRQoL and the use of health-status measures to assess HRQoL is not entirely satisfactory. Most of the questionnaires used are essentially measures of health status in a new guise and these place an overwhelming reliance on the assessment of functional capacity. As such, while purporting to incorporate patients’ perspectives, they represent implicitly a medical model that stresses the ability to perform everyday tasks and fulfil social and occupational roles. Such measures ignore the meaning and importance of such tasks and roles for the individual and often preserve the supremacy of professional judgements leading to the suppression of what is supposed to be under scrutiny (Joyce et al.1999, Hunt 1997).

5. Individual QoL Measures

A number of researchers have argued that QoL depends on the unique interpretation and perceptions of the individual and that questionnaires represent an oversimplification of what is a complex, multidimensional, subjective phenomenon. QoL is seen as a uniquely personal perception, denoting the way that individuals feel about their health status and/or nonmedical aspects of their lives. It can be measured suitably only by determining the opinions of patients and by supplementing (or replacing) the instruments developed by ‘experts.’ This/hermeneutic approach would seek to understand individuals as self-reflective beings who are responsible for their own actions and who are the best judges of their QoL. This approach has resulted in the development of a number of individualized measures of QoL such as the Schedule for the Evaluation of Individual QoL or SEIQoL (Joyce et al. 1999).

6. Future Trends And The Need For Theoretical Models

Assessment of patient QoL facilitates improved clinical intervention, assists in treatment comparisons, and should prove increasingly important in the identification of services and facilities and in resource allocation. However, much of the research, to date, has been underpinned by somewhat tautological operational definitions of QoL. There is a growing need for theoretical models that capture the psychological reality and complexity of QoL. For example, most current measures fail to address adequately the dynamic nature of QoL. Patients confronted with a life-threatening or chronic disease are faced with the necessity to accommodate to their illness. An important mediator of this adaptation process is ‘response shift’ which has been defined by Schwartz and Sprangers (2000) as changing one’s internal standards, values, or one’s conceptualization of QoL. Response shift is but one example of a psychological process that underpins the essentially dynamic and phenomenological nature of QoL. Research in this area must incorporate psychological variables into theory construction in order to produce a body of research that more validly reflects the true nature of QoL.

QoL has, heretofore, been considered solely as an outcome measure in health research. However, exciting developments in psychoneuroimmunology and evidence from a number of clinical studies raise the intriguing possibility that QoL might influence pathological processes such as tumor progression. If this were proven, then interventions aimed at maximizing patient QoL might also influence patient recovery.

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