Generic health-related quality-of-life assessment in children and adolescents: methodological considerations

The health-related quality of life (HR-QOL) of children and adolescents is increasingly considered a relevant topic for research. Instruments to assess quality of life in children and adolescents of a generic as well as disease- or condition-specific nature are being developed and applied in epidemiological surveys, clinical studies, quality assurance and health economics. This paper attempts to give an overview on the state of the art of HR-QOL assessment in children as it relates to methodological and conceptual challenges. Instruments available in international or cross-cultural research to assess HR-QOL in generic terms were identified and described according to psychometric data provided and the width of application. In an initial literature search, several challenges in the assessment of child and adolescent HR-QOL were identified, ranging from conceptual and methodological to practical aspects. Seven specific major issues were considered: (i) What are the dimensions of HR-QOL relevant for children and adolescents, and do suitable instruments for their measurement exist? (ii) Can these dimensions be collected in a cross-culturally comparable way? (iii) What advantages and disadvantages do self-rated versus externally evaluated HR-QOL measurements of children and adolescents have? (iv) How can HR-QOL be assessed in an age-appropriate way? (v) What are the advantages and disadvantages of disease-specific and generic data collection? (vi) What advantages and disadvantages do profile and index instruments have? (vii) How can HR-QOL be connected with utility- preference values? In a second literature search we identified nine generic HR-QOL instruments and four utility health state classification systems that complied with the prespecified inclusion criteria. It was concluded that (i) HR-QOL instruments are available to assess the dimensions of the construct relevant to children and adolescents; (ii) provided that an instrument was constructed in an appropriate way, the dimensions of HR-QOL can be measured in an interculturally comparable manner; (iii) the HR-QOL of children and adolescents can and should be ascertained by self-rating; (iv) the measurement instruments used have to consider maturity and cognitive development; (v) only generic quality-of-life instruments allow for an assessment of HR-QOL in both healthy and chronically ill children and adolescents; (vi) the representation of HR-QOL achieved through a singular index value is connected to strict psychometric conditions: the index instrument has to be tailored to these psychometric conditions; (vii) how far utility measures are employable with children and adolescents has to be investigated in further studies. The problem aspects identified indicate the necessity for further research. Nevertheless, instruments for assessing the HR-QOL of children and adolescents can be identified that meet the requirements mentioned above.     

A comparative review of generic quality-of-life instruments

The assessment of health-related quality of life (HR-QOL) is an essential element of healthcare evaluation. Hundreds of generic and specific HR-QOL instruments have been developed. Generic HR-QOL instruments are designed to be applicable across a wide range of populations and interventions. Specific HR-QOL measures are designed to be relevant to particular interventions or in certain subpopulations (e.g. individuals with rheumatoid arthritis). This review examines 7 generic HR-QOL instruments: (i) the Medical Outcomes Study 36-Item Short Form (SF-36) health survey; (ii) the Nottingham Health Profile (NHP); (iii) the Sickness Impact Profile (SIP); (iv) the Dartmouth Primary care Cooperative Information Project (COOP) Charts; (v) the Quality of Well-Being (QWB) Scale; (vi) the Health Utilities Index (HUI); and (vii) the EuroQol Instrument (EQ-5D). These instruments were selected because they are commonly used and/or cited in the English language literature. The 6 characteristics of an instrument addressed by this review are: (i) conceptual and measurement model; (ii) reliability; (iii) validity; (iv) respondent and administrative burden; (v) alternative forms; and (vi) cultural and language adaptations. Of the instruments reviewed, the SF-36 health survey is the most commonly used HR-QOL measure. It was developed as a short-form measure of functioning and well-being in the Medical Outcomes Study. The Dartmouth COOP Charts were designed to be used in everyday clinical practice to provide immediate feedback to clinicians about the health status of their patients. The NHP was developed to reflect lay rather than professional perceptions of health. The SIP was constructed as a measure of sickness in relation to impact on behaviour. The QWB, HUI and EQ-5D are preference-based measures designed to summarise HR-QOL in a single number ranging from 0 to 1. We found that there are no uniformly 'worst' or 'best' performing instruments. The decision to use one over another, to use a combination of 2 or more, to use a profile and/or a preference-based measure or to use a generic measure along with a targeted measure will be driven by the purpose of the measurement. In addition, the choice will depend on a variety of factors including the characteristics of the population (e.g. age, health status, language/culture) and the environment in which the measurement is undertaken (e.g. clinical trial, routine physician visit). We provide our summary of the level of evidence in the literature regarding each instrument's characteristics based on the review criteria. The potential user of these instruments should base their instrument selection decision on the characteristics that are most relevant to their particular HR-QOL measurement needs.     

Reassessing quality-of-life instruments in the evaluation of new drugs

Investigators use 2 fundamental approaches to the measurement of health-related quality of life (HR-QOL). Generic instruments include health profiles that tap into the full range of HR-QOL issues and are widely applicable, but may lack responsiveness to small but important changes in HR-QOL. Utility measures summarise HR-QOL in a single number between 0 (death) and 1 (full health) and are useful for economic analysis, but may lack responsiveness. Accumulating data suggest the alternatives to generic measures, instruments that are specific to a function or a health problem, are more responsive than generic measures. While direct comparison of the validity and responsiveness of alternative approaches remains limited and should be extended, it is already clear that comprehensive assessment of HR-QOL requires more than 1 type of instrument. To be useful, HR-QOL instruments must be interpretable. Investigators are beginning to elucidate what constitutes trivial, small but important, or large changes in HR-QOL. Approaches include both within- and between-patient global ratings, observing HR-QOL scores in different patient populations, and observing the magnitude of change in HR-QOL with established interventions.     

Quality-of-life instruments in hypertension

This review considers the choice of dimensions to be assessed and the practical problems of measuring quality of life in hypertensive patients. The dimensions of symptomatic well-being, psychological well-being, sleep, sexual function and cognitive function should be assessed. Symptomatic well-being may be measured by many different instruments, and that devised by the authors has been used extensively. The results in different trials may therefore be examined for consistency and sensitivity. Psychological well-being has been assessed by the Psychological General Well-Being Index, the Symptom Rating Test and the Profile of Mood States. The response of these instruments is discussed. The assessment of sleep, sexual function and cognitive function is also described. It is recommended that quality-of-life instruments to be employed in trials of antihypertensive drugs are known to be sensitive to the effects of such drugs.     

Measuring health-related quality of life in older patient populations: a review of current approaches

The changing demographic profile of the world's population towards old age and evidence of people living for longer with less time spent in ill health highlight the importance of addressing quality-of-life (QOL) assessment issues for older people. The assessment of health-related QOL (HR-QOL) has received considerable attention in the last 2-3 decades, with a wide variety of assessment instruments available. These instruments can be either generic or disease specific, health profiles or preference based.The literature was reviewed systematically to identify studies measuring HR-QOL in older patient groups. A total of 37 studies were identified, 11 of which were randomised, controlled trials/evaluations, 14 were prospective studies that did not involve a randomised, controlled intervention, and 12 were cross-sectional studies. Studies were summarised in terms of the study aim, patient population characteristics, the instrument used to measure HR-QOL, and HR-QOL findings. A majority of studies used a generic HR-QOL instrument, the single most commonly used being the 36-Item Short-Form Health Survey. In many cases, a second disease-specific measure was used in combination with the generic measure. In a majority of studies involving interventions, significant improvements in HR-QOL were noted. In prospective studies, a negative impact of health conditions (e.g. myocardial infarction and chronic heart failure) was also identified using HR-QOL assessments.None of the studies in this review used HR-QOL measurement instruments that were old-age specific. Using instruments that are not specific to a particular age group enables comparisons to be made with other age groups, i.e. younger or middle-aged groups. However, the questionnaire items of HR-QOL instruments tend to be phrased predominantly in relation to physical function and thus may inadvertently discriminate against older persons, whose physical function is likely to be not as good as that of younger people. Particular issues in the assessment of HR-QOL in older patient populations include the persistent finding of a poor relationship between QOL and disability/disease severity, the dynamic nature of QOL, and the importance of valid proxy ratings for those unable to make decisions or communicate for themselves.It is important, therefore, that assessment of HR-QOL incorporates issues of importance to individual older people by broadening the scope of the measurement instruments, thus representing more validly the HR-QOL status of older patient groups. Future research in HR-QOL must incorporate the perspective of the individual in order to enable valid conclusions to be derived based on content that is relevant to the individual being assessed, thus informing management decisions, policy and practice more meaningfully.     

A review of quality-of-life evaluations in prostate cancer.

Prostate cancer is a highly prevalent malignancy in older men. Because the disease and its treatments have the potential to cause substantial morbidity in affected individuals, prostate cancer has been the subject of great interest for quality-of-life (QOL) researchers. In this article, we review published QOL studies that have focused on individuals with prostate cancer. Generic survey instruments have generally been found to be insensitive to changes in health-related quality of life (HR-QOL) related to prostate cancer and its treatments. Domain-specific survey instruments (such as those focusing on sexual function) have been more sensitive, but fail to capture all relevant impacts. At least 9 disease-specific instruments have been developed to measure the HR-QOL impact of prostate cancer. These instruments generally focus on specific symptoms related to the disease and its treatment--urinary function, bowel function, sexual function, physical function, psychological function and pain--however, the domains covered are not consistent from instrument to instrument, and the domains of emphasis within each instrument are rarely the same. In addition, no single instrument has been applied to all major therapies for prostate cancer across men at different ages and stages of disease. Finally, HR-QOL evaluations in some patient groups, such as those with advanced disease, have received relatively little attention to date. As a result of the proliferation of prostate cancer-specific survey instruments and inconsistencies in their design and application, decision-makers face great difficulties evaluating HR-QOL across disease stages and comparing the HR-QOL impacts of alternative therapies, including conservative management ('watchful waiting'). In order for these tools to be useful for patient management and policy-making, coordination of instrument development efforts with the goal of consolidating the number of measures used is urgently needed.     

Subjective outcome measurement_a primer

There is a growing recognition within both the practice and research communities in pharmacy that serious attention must be given to the systematic study of the outcomes of pharmacy services, especially those outcomes that are focused on the patient. Research has tended to focus too strongly on the measurement of structure and process, with the unspoken assumption that if these are of good quality, the outcome will automatically be similar. However, the literature on outcome measurement instruments is vast and practitioners moving into this area for the first time may find themselves lost in a morass of conflicting definitions and different methods of measurement. This review considers the outcome measures or 'measurement instruments' that are used to assess subjective health status. Two commonly used taxonomies are described that concern the conceptual content (functional status, general health perceptions, quality of life and health‐related quality of life) and the breadth of coverage of the instruments (generic, disease specific, domain or dimensions specific and patient‐centred instruments). Specific attention is paid to the newest of these groups, the patient‐centred instruments, which are very different in style and content to the other three and reflect a change in direction in instrument development, to address limitations of commonly used 'fixed' outcome instruments. Detail is given on what makes a quality instrument in particular circumstances (validity, reliability, sensitivity to change, multidimensional construct, practicality and applicability), to help pharmacists develop the necessary skills to select appropriate instruments in the burgeoning field of outcomes measurement.     

Health-related quality-of-life measurement in patients with Parkinson's disease.

Outcome measures are increasingly used to assess the impact of diseases such as Parkinson's disease (PD) from the patient's perspective. These measures, in the form of questionnaires to assess health-related quality of life (HR-QOL), are of 2 main kinds: generic and disease-specific. The former is intended to be relevant to the widest range of health problems; the latter is developed specifically to assess HR-QOL for a specific condition. Possible consequences of PD have been assessed by generic instruments such as the Sickness Impact Profile (SIP), the Nottingham Health Profile (NHP), the Medical Outcomes Study 36-Item Short Form (SF-36) Health Survey and also by disease-specific instruments; in particular, the Parkinson's Disease Quality-of-Life Questionnaire (PDQL) and 39-Item Parkinson's Disease Questionnaire (PDQ-39). This article summarises the criteria whereby such instruments should be evaluated by potential users and describes in more detail the methods of developing and testing such disease-specific instruments for use in PD. There is a range of valid and feasible methods available for taking into account patients' views of PD outcomes. These will become important outcome measures in future clinical trials of treatment regimes.     

Health state values for use in the economic evaluation of treatments for Alzheimer's disease

Alzheimer's disease (AD) is a chronic, progressive, neurodegenerative disease that places a heavy burden on people with the condition, their families and carers, health care systems and society in general. Health-related quality of life (HR-QOL) in patients deteriorates as the cognitive, behavioural and functional symptoms of AD develop. The human and financial cost of AD is forecast to grow rapidly as populations age, and those responsible for planning and financing health care face the challenge of allocating increasingly scarce resources against current and future interventions targeted towards AD. These include calls for early detection and diagnosis, preventative strategies, new medications, residential care, supportive care, and meeting the needs of carers as well as patients. Health care funders in many health systems now require a demonstration of the value of new interventions through a comparison of benefits in terms of improvements in HR-QOL and costs relative to those of competing or existing practices. Changes in HR-QOL provide the basis for the calculation of the quality-adjusted life-year (QALY), a key outcome used in economic evaluations to compare treatments within and between different disease conditions. The objective of this systematic review was to provide a summary of the published health state values (utilities) for AD patients and their carers that are currently available to estimate QALYs for use in health economic evaluations of interventions in AD. The health care literature was searched for articles published in English between 2000 and 2011, using keywords and variants including 'quality-adjusted life years', 'health state indicators', 'health utilities' and the specific names of generic measures of HR-QOL and health state valuation techniques. Databases searched included MEDLINE, EMBASE, NHS EED, PsycINFO and ISI Web of Science. This review identified 12 studies that reported utility values associated with health states in AD. Values for AD health states categorized according to cognitive impairment (where 1 = perfect health and 0 = dead) ranged from mild AD (0.52-0.73) to moderate AD (0.30-0.53) to severe AD (0.12-0.49). Utility values were almost all based on two generic measures of HR-QOL: the EQ-5D and Health Utility Index mark 2/3 (HUI2/3). There were no health state values estimated from condition- or disease-specific measures of HR-QOL. The review also identified 18 published cost-utility analyses (CUAs) of treatments for AD. The CUAs incorporated results from only three of the identified health state valuation studies. Twelve CUAs relied on the same study for health state values. We conclude that the literature on health state values in AD is limited and overly reliant on a single symptom (cognition) to describe disease progression. Other approaches to characterizing disease progression in AD based on multiple outcomes or dependency may be better predictors of costs and utilities in economic evaluations. Patient and proxy ratings were poorly correlated, particularly in patients with more advanced AD. However, proxy ratings displayed the validity and reliability across the entire range of AD severity needed to detect long-term changes relevant to economic evaluation. Further longitudinal research of patient and carer HR-QOL based on multidimensional measures of outcome and utilities is needed.     

Sociodemographic differences in quality of life in rheumatoid arthritis

Assessment of health-related quality of life (HR-QOL) in people with rheumatoid arthritis (RA) has become important in health research and can inform clinical care. Many studies have found sociodemographic differences in the HR-QOL of people with RA, and interpreting these differences can be challenging. Biological, health disparity, reporting and assessment instrument differences are a few of the possible explanations that should be considered when interpreting results. Our review of the evidence of sociodemographic differences in HR-QOL in people with RA produced 34 articles describing 49 studies.Typically, patients with RA who were older, female, less educated, non-employed and/or less affluent tended to have significantly lower HR-QOL than other groups. Some evidence also indicated that people with RA who are non-White or who live in rural settings may also tend to have lower HR-QOL scores, but the number of studies supporting these findings was sparse.Researchers and clinicians can optimise their assessment of HR-QOL by finding well validated instruments for the context they are working in. Additional research is needed to identify the exact causes of HR-QOL differences so that quality treatment can be provided to those in need.     

Onychomycosis: health-related quality of life considerations

The symptoms of onychomycosis and their impact on personal appearance are important determinants of patients' perceptions of their own health. The effect of onychomycosis is greater on psychosocial than physical functioning and is directly related to the extent of nail involvement. This review identified a number of disease-targeted questionnaires that have been developed to assess the impact of onychomycosis and its treatment on health-related quality of life (HR-QOL). The instruments differ considerably in the extent to which they have been psychometrically tested. Most have been shown to provide both valid and reliable measurement of HR-QOL in patients with onychomycosis of the toes. However, not all have been tested in patients with fingernail disease. The generic and disease-targeted scales of most of the available questionnaires exhibit poor variability, which may limit their responsiveness to clinically important change. Only one instrument, the Onychomycosis Disease-Specific Questionnaire, has been incorporated into a clinical trial. Thus, information relating to the impact of onychomycosis treatment on HR-QOL is limited. Future efforts should focus on the systematic evaluation of existing questionnaires in all populations for which they were developed. In addition, it is important that disease-targeted measures be included in future clinical trials so that a better understanding of the impact of onychomycosis treatment on patient HR-QOL may be gained.     

The impact of fragility fracture on health-related quality of life : the importance of antifracture therapy

Both general and specific health status instruments can be utilised in evaluating health-related quality of life (HR-QOL) deficits resulting from osteoporotic fractures. Osteoporotic hip, vertebral and wrist fractures significantly decrease HR-QOL in most HR-QOL domains investigated. The presence of multiple vertebral fractures leads to larger decrements in HR-QOL. More research needs to be completed with these HR-QOL tools to better assess the true burden of osteoporotic fractures, particularly in the case of hip fractures, as the burden is surely being underestimated without recognition of HR-QOL. Only when the burden of fragility fractures is understood, inclusive of HR-QOL, will the value of proven antifracture prevention and treatment therapies be appreciated. Information collected by HR-QOL instruments may provide new insight as to how to improve quality of life for patients with fractures and how to properly allocate healthcare spending.     

Evaluating health-related quality-of-life studies in paediatric populations: some conceptual, methodological and developmental considerations and recent applications

Although numerous paediatric-based health-related quality-of-life (HR-QOL) instruments are currently in use, there still remain conceptual, methodological and developmental issues to address. This paper provides an up-to-date critical review of the HR-QOL literature in paediatric medicine.Our analysis indicates that there is no consensus on how HR-QOL and overall QOL should be defined and measured in children. It is recommended that future studies focus on operationalising and distinguishing these constructs from each other and from traditional health-status measures. A clear empirical basis for generating instrument items and for prioritising specific domains must be described. Researchers should consider using the data gathered during their first interviews as a springboard from which to test their ideas of HR-QOL and QOL, reformulate concepts and subsequently retest their notions before developing instruments.Related to methodological challenges, consistency and agreement are still used interchangeably when comparing child and parent reports of children's HR-QOL. The Pearson correlation is a measure of co-variation in scores, and not a measure of agreement. We recommend that researchers focus on determining agreement as opposed to consistency. Few, if any, attempts have been made to account for the possibility that a response shift may have occurred in the evaluation of HR-QOL. Most studies have compared HR-QOL scores of children with illness with their healthy peers. As such, there is a dearth of knowledge regarding the normative process of adaptation within the context of illness. It is recommended that researchers focus on gathering data using a relative standard of comparison. We further recommend that researchers interpret HR-QOL data in line with their intended purpose. Regarding developmental consideration, particular attention ought to be paid to developing instruments that consider children's emerging sense of self, cognitive capacity and emotional awareness. Instruments that include items that are age appropriate are more likely to maximise reliability and validity of reports.The results of many HR-QOL instruments are applied in pharmacotherapeutic and pharmacoeconomic assessments. However, there has been relative infrequent application of economically valid HR-QOL tools (utility scales) and the use of HR-QOL scales as outcome measures in paediatric drug trials. As such, few cost-utility analyses have been performed to inform paediatric decision making. In addition, many of the concerns in the development of HR-QOL instruments should also be applied to the utility scales such that they reflect adequately children's preferences for health states.     

Health-related QOL in acute exacerbations of chronic bronchitis and chronic obstructive pulmonary disease: a review of the literature

There is a lack of emphasis on health-related QOL (HR-QOL) changes associated with acute exacerbation of chronic bronchitis (CB) or chronic obstructive pulmonary disease (COPD). The aim of this review is to examine the use of HR-QOL instruments to evaluate acute exacerbation of CB or COPD, so as to form recommendations for future research.A literature search of papers published between 1966 and July 2003 identified more than 300 articles that used acute exacerbation of CB or COPD as the search term. However, only 21 of these studies employed HR-QOL measures as predictors of outcome or in the assessment of the impact, evolution or treatment of acute exacerbations of COPD or CB. A variety of HR-QOL measures were used, both generic and disease specific. The disease-specific St George's Respiratory Questionnaire (SGRQ), devised for patients with stable CB and with a recall period of 1-12 months, was the most widely used measure, with the Chronic Respiratory disease Questionnaire (CRQ) and the Baseline and Transitional Dyspnoea Index (BDI, TDI) being the only other disease-specific measures used.Most measures, both generic and disease specific, performed adequately when used during acute exacerbation of CB or COPD and indicated poor HR-QOL during acute exacerbation, which improved on resolution of the exacerbation. Relationships were evident between HR-QOL during an acute exacerbation and various outcomes, including post-exacerbation functional status, hospital re- admission for acute exacerbation or COPD, and mortality.There is a need for studies of treatments for acute exacerbation of CB or COPD to include an appropriate HR-QOL instrument to aid in the stratification of patients so as to target the right treatment to the right patient group. While a new instrument could be developed to measure HR-QOL during acute exacerbation of CB or COPD, currently available disease-specific measures such as the CRQ and the SGRQ appear to be acceptable to patients during acute exacerbation. However, the recall period of the SGRQ symptoms component should be shortened to make it more appropriate for use during acute exacerbation.     

Assessment of quality of life in rheumatoid arthritis: methods and implications

During the last decade, self-report of health status and quality of life has gained increasing credibility and acceptance in studies of individuals with rheumatoid arthritis (RA). According to a number of reports, the new self-assessment instruments offer an excellent complement to the more traditional clinical outcome measurements. In the absence of a cure for RA and the use of potentially toxic drugs, quality-of-life assessment seems to have an important place in clinical drug trials. The most commonly used quality of life or health status instruments in studies of RA seem to perform well and give reliable and valid information. A common concern, however, with these instruments is that there appears to be a lack of questionnaires which allow satisfaction with various aspects of quality of life to be expressed. Many instruments focus on negative aspects of quality of life, although quality of life for most individuals is related to something positive. There is no perfect instrument applicable for all situations, but the selection of an instrument depends on the specific purpose of a particular study. Psychological interventions are more likely to affect people's emotions and well-being, whereas a drug intervention might more dramatically affect physical function. It appears, however, reasonable to assume that effects of drug intervention on quality of life should be measured with a longer perspective, such as after at least 6 months' observation. The field is still in a phase of methodological and theoretical development which is also reflected in the few numbers of published studies concerning the effect of drug interventions on quality of life of patients with RA.     

Vision-specific instruments for the assessment of health-related quality of life and visual functioning: a literature review

Clinically objective measures such as visual acuity or visual field provide an assessment of a patient's visual status. However such measures may not reflect the degree of visual impairment the patient experiences in his or her daily activities. Visual impairment has been shown to have negative effects on health-related quality of life (HR-QOL) and a significant impact on daily functioning, including social activities. As such, there is a growing recognition of the importance of patient-reported outcomes of visual functioning. This review examines the development and psychometric properties of 22 vision-specific instruments assessing visual functioning and/or the impact of visual impairment on HR-QOL or daily activities. Issues relevant to assessing vision-specific subjective outcomes are reviewed, with specific application of the reviewed instruments. Three instruments, the Activities of Daily Vision Scale, National Eye Institute Visual Function Questionnaire, and Visual Function Index have been well validated and widely used, but others also show promise. To fully capture the benefits of a new ophthalmology treatment (or new treatment for eye disease) a valid and reliable visual instrument, in which the psychometric performance has been demonstrated in the particular ocular condition being treated, should be utilised.     

Quality of life among alcohol-dependent patients: How satisfactory are the available instruments? A systematic review

Aim

The purpose of this systematic review was to compare quality-of-life instruments used as outcome measures in randomized clinical trials for alcohol-dependence treatment.

Methods

Randomized controlled clinical trials, indexed in the EMBASE, PubMed and PsycINFO databases since 1981, which aimed at improving the quality of life in alcohol-dependent patients and used as instrument to measure the quality of life, as specifically designated by the authors, were included.

Results

Of the 331 articles screened, 18 studies were included in the review. Eight different quality-of-life instruments were used as outcome measures. Twenty-seven life domains were explored. Between-scale heterogeneity was high. The scale most frequently used was the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). Only 1 clinical trial demonstrated a significant difference between intervention groups at all endpoints, using the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q).

Conclusion

Because many different instruments were used, it is difficult to compare quality-of-life improvement between trials. The most frequently used instrument was a generic health status measure that may not be well suited as a quality-of-life measure for subjects with alcohol dependence. The construction and validation of a specific patient-reported outcome based on alcohol-dependent patients’ concerns would effectively contribute to the assessment of treatment efficacy.     

Subjective outcome measurement--a primer.

There is a growing recognition within both the practice and research communities in pharmacy that serious attention must be given to the systematic study of the outcomes of pharmacy services, especially those outcomes that are focused on the patient. Research has tended to focus too strongly on the measurement of structure and process, with the unspoken assumption that if these are of good quality, the outcome will automatically be similar. However, the literature on outcome measurement instruments is vast and practitioners moving into this area for the first time may find themselves lost in a morass of conflicting definitions and different methods of measurement. This review considers the outcome measures or 'measurement instruments' that are used to assess subjective health status. Two commonly used taxonomies are described that concern the conceptual content (functional status, general health perceptions, quality of life and health-related quality of life) and the breadth of coverage of the instruments (generic, disease specific, domain or dimensions specific and patient-centred instruments). Specific attention is paid to the newest of these groups, the patient-centred instruments, which are very different in style and content to the other three and reflect a change in direction in instrument development, to address limitations of commonly used 'fixed' outcome instruments. Detail is given on what makes a quality instrument in particular circumstances (validity, reliability, sensitivity to change, multidimensional construct, practicality and applicability), to help pharmacists develop the necessary skills to select appropriate instruments in the burgeoning field of outcomes measurement.