Health-related quality of life

The goal of treatments for multiple sclerosis (MS) and other chronic neurological conditions that produce morbidity but have limited effect on mortality is to reduce disease impact on patients’ lives and to assure that interventions result in more good than harm. A measure of our success in reaching these goals can be made only with direct information from patients about how they experience the illness and the effects of treatments. Patient-derived data are increasingly accepted as an essential assessment domain in clinical research and treatment. Research shows that measures of patient perception and clinician-derived data are not redundant. ± 3 Observation of patient functioning in the clinic is not sufficient in itself since it has been determined that patient functioning in the artificial setting of the treatment center is not always duplicated at home. The approach to patient assessment that is considered relevant in monitoring the consequences of diseases and their treatments is known as `health-related quality of life’. Quality of life is one domain of health as defined by the World Health Organization (WHO). Health-related quality of life (HRQoL) is a discrete component of general quality of life. While general quality of life can be affected by many factors beyond the scope of health care including economic instability, civil unrest or poor environment, these have only an indirect relationship with HRQoL and are not included in its definition. While such factors as equal opportunity and social security are important to community health, these extend beyond the more immediate goal of treating the sick. This thinking led to the HRQoL definition: `Quality of life’ in clinical medicine represents the functional effect of an illness and its consequent therapy upon a patient, as perceived by the patient’. Although there is variation in terminology, this construct includes four broad domains: physical and occupational function, psychological function, social interaction and somatic sensation. Several operational characteristics of HRQoL assessment help to further define the construct. First and foremost, HRQoL is subjective. As Schipper and his colleagues explain `. in clinical medicine the ultimate observer of the experiment is not a dispassionate third party but a most intimately involved patient’. They note that since the goal of treatment is to minimize the manifest consequences of disease, HRQoL represents `the final common pathway of all the physiological, psychological and social inputs into the therapeutic process’. The second characteristic of HRQoL is that it is multifactorial. Having defined HRQoL as the integration of four domains, it is important to assure that patients’ daily experiences in each domain are explored in the questionnaire, albeit in a manner that is parsimonious and minimizes respondent burden. The third characteristic is self-administration: because HRQoL is subjective, there is concern that external administration would in some way influence patient report. The final characteristic is that HRQoL is time variable; it fluctuates. Progress in HRQoL assessment in research or clinical monitoring is evolutionary and, arguably, comparable to the increasing use of MRI and immunological markers in quantifying MS severity. Data derived from HRQoL measures are used for three general purposes. The first, most commonly used in research, is to classify or group patients by levels of disease severity. The second is to monitor for change in status that indicates a need for modifying the treatment plan or to predict the health of subjects at a future point in time. The third use is as an outcome variable in clinical research. HRQoL assessment is increasingly accepted as an outcome measure in MS research for disease-modifying treatments ± 11 and symptom management. ± 14 HRQoL assessment is less commonly used to monitor patient well-being as part of the usual process of care. This can be done routinely, in much the same way that upper and lower extremity monitoring is done using the NineHole Peg Test or Timed Twenty-five Foot Walk. However, challenges to using HRQoL monitoring in clinical practice are the limited availability of instruments proved to be sensitive to change in individual patients over time, easily interpreted by clinicians, accepted by patients as relevant, and that require limited time to complete. Quality of life researchers are actively engaged in improving the science of HRQoL interpretation at the individual level; it remains an emerging field. In this issue, Shawaryn describes a measure of illness intrusiveness that has good potential for use as an HRQoL screening instrument in the clinical setting. Her findings clearly demonstrate that the physical and cognitive aspects of MS affect HRQoL, each in different ways. Her findings hold for HRQoL as measured directly by the Multiple Sclerosis Quality of Life Inventory and indirectly, by the Illness Intrusiveness Rating Scale. This later measure has a number of benefits for clinical use including brevity, face validity, clinical relevance and patient acceptability. Even though there are not yet standard methods for determining when a change in this or other patient self-reported measures indicates a need to review or revise a patient’s treatment plan, these measures have an important use for physicians providing care to patients with MS and other chronic conditions. Routine use of such measures allows physicians to review, quickly and systematically, patient functioning and concerns and to help patients to become active participants in their care.