Measuring quality of life in britain

Abstract

Quality of life is an important outcome measure in the evaluation of treatments for a range of chronic physical and psychological disorders. The psychometric properties of a new British quality-of-life instrument—the WHOQOL-100—are presented, as part of an international project to create a multilingual, multidimensional profile for cross-cultural use. The WHOQOL was completed by an adult sample (N=320) of well people and patients attending GP surgeries and out-patient clinics and from in-patient wards. The sick represented 16 disease categories and all were selected for age, gender, and disease severity. The levels of quality of life of different disease groups and sociodemographic categories are reported. The presence or absence of positive feelings provides the best single predictor of quality of life in Britain today, and this improves when supplemented by information about mobility and energy. The scores of the scale discriminate well between sick and well people and concur with reported health status. The concept of quality of life covering 25 facets (hierarchically organized within six domains) was largely confirmed by mapping intercorrelations. The WHOQOL-100 shows excellent overall internal consistency reliability and can be used with individuals. This level of reliability extends to all domains and patient subgroups. Seven UK national items were also assessed for inclusion. The results show that WHOQOL-100 promises to be a comprehensive profile for generic use in the evaluation of contemporary health care.

Introduction

Demand is increasing for a good quality-of-life measure that will enable health and health care interventions to be properly evaluated, and such an instrument can assist with policymaking and planning in health service. The concerns and perceptions of the patient are central to the assessment of quality of life and thus subjective measures must be both applicable and acceptable to the people who use them. Any new scale for use in health settings must at the same time display the valued psychometric properties of sensitivity to changes in clinical condition as well as reliability and validity [1]. The present study investigates some of the psychometric properties of a new quality-of-life assessment, which may be of use in British health care—the UK WHOQOL-100. This instrument has been designed through collaborative work with the WHOQOL Group, originating from the World Health Organisation (WHO), Geneva, and is currently available in more than 40 languages worldwide (WHOQOL Group, 1995, 1998). It will be most useful in multinational clinical trials for the evaluation of quality-of-life outcomes during all types of health care interventions; for instance, surgery, counseling, and medication. The measurement of quality of life is especially salient to the care of those with serious and chronic diseases, where recovery may be partial, remission rates high, and care often palliative. It will also be useful for making cross-cultural comparisons about perceived quality of life relating to health and, at a one-to-one level, in improving communications between doctors and their patients in the consulting room.

There is considerable debate about the definition of quality of life. It is frequently confused with standard of living; square feet of living space in Tokyo and Los Angeles provide a comparative illustration of why such indicators have not succeeded in measuring quality of life cross-culturally. It is the meaning of these resources or conditions that tell us about quality of life and, inevitably, these meanings will be grounded in cultural values. Indeed, many items are claimed to be quality-of-life indicators, although these claims are equivocal. For instance, in a review of recent clinical trials, Hunt [2] noted that the measurement of quality of life has been variously confused with the incidence of psychiatric morbidity, number and severity of symptoms, cognitive ability, social contact, the ability to work, physical capacity, and the frequency of diarrhea.

Quality of life cannot be measured with objective indicators because it is a subjective experience. Hence, the best person to assess quality of life is arguably the individual themselves. For instance, a clinician who wants to know about how sleep affects quality of life might ask questions about length of sleep time, early waking, interruptions to sleep, use of sleeping pills, and so on. But answers to these questions do not provide a direct insight into that person's quality of life because they require interpretation. Any such interpretations necessarily bring to bear the attitudes, beliefs, and expectations of the judge and must be based on limited (usually observable) information. Therefore, the conclusion reached by a judge about that person's quality of life may be far from accurate, and inaccuracy is a prime reason why clinician ratings of quality of life have shown only limited clinical success in the history of the subject. We may question the quality of life of a person who sleeps 3 hours a night. The important issue in quality-of-life assessment is not how many hours a person sleeps but whether, when waking, their sleep has been refreshing. Questions about how satisfied or bothered people are about important aspects of life provide not only an individual profile about how that person perceives their condition but also could be used as a primer for clinical action in areas deemed to be problematic. The best way to find out about a person's quality of life is therefore to ask them, and then to supplement this assessment with the usual clinical observational information.

Last, where subjective qualities of life have been evaluated in health care, they have often been restricted to a relatively small number of dimensions. Among published scales, the most popular of these dimensions has been functional status for physical illness (covering mobility and activities of daily living) and negative mood for psychological disorders. Although these are undoubtedly important aspects of life, many other properties may also be important and, to date, these remain largely unevaluated. This is due to restricted consensus about what dimensions are essential to a comprehensive assessment of quality of life. It is also due to clinical pressure about providing short scales to ease the clinical burden. Some quality-of-life instruments have compiled the “best” items available and, although this is laudable from a measurement viewpoint, it has resulted in a tendency to lose sight of the entirety of the concept of quality of life, conceptual poverty in the field, and increasing similarity among instruments. But, in 1991, the WHOQOL Group took a fresh look at the comprehensiveness of the concept of quality of life and carried out this work internationally in an attempt to establish its most important global dimensions.

The WHO's definition of health is “a state of complete physical, mental and social well-being, not merely the absence of disease or infirmity” [3]. In the spirit of this statement, quality of life was defined by the WHOQOL Group as “an individual's perceptions 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 the person's physical health, psychological state, level of independence, social relationships and their relationship to salient features of their environment” [4]. A sixth domain, addressing spirituality, religion, and personal beliefs, was subsequently added to the list in this definition following recommendations by focus groups. In psychosomatic research, it is necessary to give equivalent weight to the assessment of both the physical and psychological aspects of a disorder and this Cartesian dualism underpins the WHOQOL concept. The WHOQOL is intended for use by those with chronic diseases, well people, informal caregivers, and people living in highly stressful situations, such as refugees and migrants. It is a subjective assessment for adults with a reading age of 8 years and above, but can also be completed with interviewer assistance.

To develop this multidimensional, multilingual, generic profile, a manual defining 33 aspects or facets of quality of life was constructed to provide instructions that could assist focus groups in the task of composing questions or items that would later be included in the WHOQOL instrument [5]. Labels attached to five-point Likert interval rating scales were also developed by each center [6]. From a pool of over 2000 questions generated by focus groups of patients, health professionals, and community members carried out in 15 centers, a pilot version of 276 items was selected to form the international core questions [7]. National items specific to the language and culture of a particular center were allowed be appended to the core where focus groups showed that those concepts were not fully addressed in that culture (e.g., skin color in India). Four national items representing specific concerns in Britain were included (e.g., feeling “fed up”). Results showed that 29 aspects of quality of life were important international features of quality of life (Table I). General questions on overall quality of life and health were added. For each facet, questions about its importance to quality of life were included.

The content and organization of items, facets, and domains has undergone several revisions throughout the dual and reflexive processes of establishing the conceptual structure and reducing the item pool, first using qualitative, then quantitative, international consensus. The method allows for the inclusion of important semantic and conceptual features pertaining to the main aspects of quality of life in that population, and hence equivalence between versions could be achieved [4]. This common, centrally directed, “spoke-wheel” procedure enables standards to be maintained across centers, and for a number of different language versions to be developed simultaneously. Hence, the WHOQOL differs in its method of development from that of previous instruments where, in a sequential process, a scale designed in one language showed only limited semantic and conceptual equivalence when translated into subsequent versions. The WHOQOL is genuinely cross-cultural in the manner in which it was created [8] and this method of simultaneously developing versions in many cultures represents a “fast track” to international use [9]. Furthermore, the manual designed for focus group use provides a common central tool and a blueprint for the creation of potentially hundreds of different language versions (Table I).

Some psychometric properties of the WHOQOL have been examined in a global sample obtained from 15 centers (N=4802) [10]. The UK instrument performed at a very high level and was largely consistent with the international model. An examination of results across global centers enabled weak items to be deleted and changes to the conceptual structure to be made, hence facets on sensory functioning, dependence on nonmedicinal substances, communication capacity, activities as provider/supporter, and work satisfaction were deleted (see Table I). Mapped global intercorrelations showed that sexual activity should be moved from the physical to the social domain. Four psychometrically superior items from each of the remaining 25 facets (hierarchically grouped within six domains) were selected for the WHOQOL-100 and 32 importance items were retained as an appendix to this international core [10].

Thirty-one items contributed by UK focus groups were included in the 276-item pilot version of the WHOQOL. Of the 176 items discarded during the selection of the WHOQOL-100, 18 were UK items, and these were now reassessed as potential national items. Internal consistency reliability was good for all these national items (Cronbach's α ranged from 0.68 to 0.77). However, 15 were deleted where there was semantic overlap and/or high correlations with international core items (five items), where scores did not significantly distinguish between sick and well samples (seven items) and where there were consistent patterns of missing data (three items). Consequently, the remaining three items were added to the original four national items and these were assessed and compared with the performance of the international items in the WHOQOL-100. This article reports the preliminary psychometric properties of the WHOQOL-100 for a British sample. The purpose of this study was to examine internal consistency reliability, construct validity, and discriminant power for the instrument using a heterogeneous cross-section of sick and well people. A secondary aim was to examine any effect on these results when the UK national items were included.