CHAPTER 3 Quality of Life Measurement Instruments
KEY POINTS
Quality of life assessment tools have emphasized the impact of lymphedema on people’s lives.
These tools have also shown the benefits of treatment.
Validated condition-specific tools for lymphedema are available.
It is recommended that these tools be used in clinical practice and research.
In many countries, lymphedema is an underrecognized condition that is not seen as a priority by health care providers. It is often believed that lymphedema is solely related to cancer treatment, that it is rare, that it causes little in the way of morbidity, that it does not reduce life expectancy, and that there is no successful treatment for it. During recent years, growing evidence has shown that these beliefs are false. There is a greater understanding of the breadth of the problem beyond its association with cancer. This understanding includes the idea that lymphedema is more common than previously thought and causes significant morbidity among a population with an increasing life expectancy. In addition, there are a growing number of treatments that may improve lymphedema symptoms. Fundamental to this improved understanding has been research into the impact of lymphedema on an individual’s quality of life (QOL) and the improvement of QOL with treatment. This chapter will look at the QOL assessment tools available for patients with lymphedema and some of the challenges associated with the use and interpretation of these tools.
Quality of Life: Definition and Measurement Tools
Defining QOL can be challenging. Every individual will have his or her own view about what constitutes a “good” QOL, and this may vary over time. Cultural and social backgrounds, age, and expectations will all influence this view. However, in the context of health-related QOL, the following components are usually considered most important 1 :
Physical health (symptoms and signs of illness)
Physical functioning (the ability to carry out daily activities)
Social health (maintaining social relationships)
Social functioning (the ability to carry out social activities)
Psychological wellbeing (for example, the absence of psychological distress and anxiety)
Emotional wellbeing (for example, life satisfaction and coping skills)
More information about these components and their relationship with lymphedema can be found in Chapter 2.
The World Health Organization has developed an International Classification of Functioning, Disability and Health (ICF). 2 This tool aims to describe and measure health and disability, and it is particularly relevant to individuals with chronic conditions such as lymphedema. A common international approach enables the comparison of the effects of lymphedema among affected individuals in different countries, and it also allows for comparison with other conditions.
The impact of a condition on an individual’s QOL can be assessed in a number of ways. Qualitative methods such as structured interviews of individuals or focus groups can be used to derive common themes that affect people with particular conditions. For example, in a study of women with lower limb lymphedema after surgery for gynecologic cancers, such themes included impact on body image and mobility and shock related to the permanence and severity of the problem. 3
Quantitative methods usually involve the use of a specific QOL measurement tool in the form of a questionnaire completed by a patient. Qualitative methods such as those described previously may be used in the development of such quantitative tools to ensure their validity.
Quantitative methods have the advantage of producing scores that can then be combined to describe QOL in certain populations and to show changes in scores as a result of treatment. Most QOL tools have a number of response options that represent degrees of severity. These may be divided into categories by descriptive terms or scored numerically via a visual analog scale (for example, pain can be graded on a scale of “None” to “Severe” or 0 to 10).
The process of the development and validation of QOL tools should ensure that they provide meaningful results, which are discussed later in this chapter. However, most QOL life tools do not incorporate a method of “weighting” individual items and therefore can be criticized for not always accurately reflecting what matters most to a particular patient. For example, for one person, the ability to function independently may be the most important factor; for another, it may be the impact of lymphedema on body image that is of most concern.
Some QOL tools, such as the Schedule for the Evaluation of Individual Quality of Life (SEIQOL-DW), 4 have been specifically designed to allow patients to prioritize the QOL aspects that are most important to them. Patients then rate their level of satisfaction or functioning against each of the nominated areas and indicate the relative contribution of each to their overall QOL.
Similarly, the Measure Yourself Medical Outcome Profile (MYMOP) is a tool that allows patients to designate their most important symptoms, which can then be scored and reassessed after treatment to measure the outcome of an intervention. 5 MYMOP also incorporates measures of self-selected physical, social, and mental activities and a general feeling of wellbeing.
Health-related QOL tools can be general (applicable to health in general and a variety of specific conditions) or condition specific (designed to measure the impact of a particular condition). Most QOL tools cover a number of domains; these are sections that encompass common themes, such as physical health, physical and social functioning, and emotional and psychological health. Usually these domains are scored separately, and then a combined score reflects overall QOL. For patients with lymphedema, general health-related QOL scores have been used in several studies, but these may not be as accurate or informative as condition-specific tools, which have been developed more recently. 6
Use of Quality of Life Tools
Health-related QOL tools, including those that assess the effects of lymphedema, can be used in both clinical practice and research settings. In clinical practice, a QOL tool may facilitate the initial assessment of an individual with lymphedema by demonstrating the impact of the condition on that individual. This can then aid in the planning of treatment. If repeated measures are used, they may be able to demonstrate the effect of treatment for the individual.
The combining of such outcomes of treatment for individuals seen by a lymphedema service allows QOL tools to be used in a clinical audit to demonstrate service outcomes. However, it is important that these outcomes be combined with other measures such as limb volume, some understanding of the type and severity of the lymphedema or chronic edema, the comorbidities experienced by the patient, and other environmental factors so that a realistic appraisal can be made. For example, the outcomes of treating early lymphedema related to breast cancer in otherwise healthy individuals are likely to be better than those obtained when treating complex leg edema in immobile elderly patients who may have other comorbidities and who do not have access to caretakers who will help them to put on and take off compression garments.
In research, QOL tools can be used to measure the impact of lymphedema in a population, and this can help to determine the health needs of that population. These tools can also be used to assess the impact of new treatments in clinical trials. In this type of setting, QOL tools are usually combined with other outcome measures (for example, a reduction in limb volume) to obtain a more detailed assessment.
QOL tools can also be used to facilitate the making of economic decisions about investments in health care. For example, these tools are used by the National Institute for Clinical Excellence in the United Kingdom. The method of cost-utility analysis involves the use of measured outcomes to create a score of health that is derived from a combination of the duration of life and an index of the patient’s health state (in other words, the patient’s QOL). The EuroQOL-5D 7 is a five-item score of an individual’s health state that can be expressed on a continuum from 0.0 (death) to 1.0 (perfect health). These values are called “utilities,” and they can be combined with the length of life to give a single index known as the quality-adjusted life year (QALY). For example, living 1 year with a utility of 1.0 (perfect health) would equate to 1 QALY; living 2 years with a health utility of 0.5 would also equate to 1 QALY. Cost-utility analysis involves the use of this concept but attaches a financial cost per QALY. Thus QALYs constitute a single outcome measure that can be costed, and comparisons can be made among different treatments for a particular condition and to assess the costs of treating different conditions. This enables decisions to be made about whether to invest in certain treatments. 8
Quality of Life Tools: Validation Process
QOL tools to be used in research and clinical practice should undergo a robust validation process. Although methodologies may vary to some extent in different publications, there are some standard themes that are usually addressed during this process:
Validity: Is the tool measuring what it was designed to measure?
Reliability: Does the tool produce similar results under different conditions? Are results repeatable?
Responsiveness: Does the tool detect significant changes after an intervention?
The details of relevant methodologies can be found in the literature that describes the validation of individual tools. 9 – 13 There are also consensus guidelines produced by the COSMIN initiative, which seeks to improve health measurement instruments. 14
Quality of Life Measures Used in Lymphedema Studies
The Short Form (36) Health Survey (SF-36) has been the most commonly used QOL assessment tool, and one study has suggested that it is the most appropriate tool to use for patients who have lower limb lymphedema. 15 However, this study took place before the development of most of the lymphedema-specific tools, which are described later in this chapter.
The SF-36 covers eight subscales:
Vitality
Physical functioning
Bodily pain
General health perceptions
Physical role functioning
Emotional role functioning
Social role functioning
Mental health
A score of 0 on this scale represents the worst possible level of health, and a score of 100 represents the best possible health.
Other general QOL tools that have been used in studies of lymphedema include the following:
SF-36 Medical Outcome Study-Short Form (36 items) 16
Nottingham Health Profile Part 1 (38 items) 17
The EuroQOL Group’s EuroQOL-5D (5 items) 7
The World Health Organization Disability Assessment Scale (WHODAS) based on the ICF described previously (12- and 36-item versions) 18
CANCER-SPECIFIC QUALITY OF LIFE TOOLS
Much research regarding lymphedema has focused specifically on lymphedema related to cancer and particularly to breast cancer. As a result, a number of cancer-specific QOL tools have been used in studies of lymphedema related to breast cancer treatment (Table 3-1). These tools can be used together to evaluate a specific aspect of treatment, as follows:
The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire, with 30 core items (EORTC QLQ-C30), plus the breast cancer supplement, with 23 items (EORTC QLQ-BR23) (see Chapter 2)
The Functional Assessment of Cancer Therapy-Breast Cancer, with 36 items (FACT-B), plus the FACT-B + 4, which includes an additional four items to address issues such as arm swelling 19
The Psychosocial Adjustment to Illness Scale (PAIS) (see Chapter 2)
Related posts:
CHAPTER 2 Lymphedema and Its Impact on Quality of Life
CHAPTER 1 Lymphedema: Lack of Solutions to a Clinical Problem
CHAPTER 16 Lymphedema in Pediatric Patients
CHAPTER 29 Conservative Treatments for Lymphedema
CHAPTER 35 Lymphaticovenular Anastomosis
CHAPTER 43 Lymphedema Complications and Their Treatment
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