Commentary
Health-related quality of life measurement in pharmaceutical care Targeting an outcome that matters • N a d i r M . K h e i r , J . W. F o p p e v a n M i l , J o h n P. S h a w a n d J a n i e L . S h e r i d a n
Pharm World Sci 2004; 26: 125–128. © 2004 Kluwer Academic Publishers. Printed in the Netherlands. N.M. Kheir (correspondence, e-mail:
[email protected]), J.P. Shaw, J.L. Sheridan: The School of Pharmacy, Faculty of Medical and Health Sciences, Auckland University, New Zealand J.W.F. van Mil: Pharmacy Practice Consultant, Margrietlaan 1, 9471 CT Zuidlaren, The Netherlands Key words: Humanistic outcomes Patient outcomes Pharmaceutical care Pharmacists Quality of life Abstract The shift in emphasis of healthcare from dealing only with disease and death to also managing illness, meant that healthcare providers started to realise the importance of assessing the quality of the patient’s life as a new therapeutic outcome. This is equally true in the evolving concept of pharmaceutical care, the ultimate target of which is improving the patient’s quality of life (QoL) through a cooperative alliance between the pharmacist and the patient. This article discusses the place of QoL assessment in today’s healthcare environment, with special emphasis on its use in the practice of pharmaceutical care.
care philosophy, was subsequently adopted worldwide. Different countries have adopted different approaches to pharmaceutical care training, implementation, and marketing. For example, New Zealand was among the countries that embraced the concept of pharmaceutical care, registered by the Pharmaceutical Society of New Zealand (PSNZ) as Comprehensive Pharmaceutical Care (CPC ®). The PSNZ adopted the American Pharmaceutical Association (APhA) definition of pharmaceutical care, which described it as ‘a patient-centered, outcomes-oriented pharmacy practice that requires the pharmacist to work in concert with the patient and the patient’s other healthcare providers to promote health, prevent disease, and to assess, monitor, initiate, and modify medication use to assure that drug therapy regimens are safe and effective’. Considering what the word health comprises (i.e., physical, social and psychological dimensions), this definition does encompass improvement in QoL.
Accepted October 2003
Introduction Interest in the concept of health-related quality of life (QoL) and its value as a health outcome is relatively new, having evolved during the last 20 years or so. It was in 1948 that the World Health Organisation (WHO) defined health as ‘a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity’ 1. This definition has broadened the concept of health beyond the biomedical model which previously guided physicians towards viewing the state of health as one that falls within acceptable biological norms and that is measured by biochemical markers 2. Raeburn and Rootman described this definition of health as being an expansive definition, and one that provides a challenge for finding new ways of promoting health 3.
QoL and pharmaceutical care The second ‘Pharmacy in the 21st Century’ Conference held in Williamsburg (USA), in 1989, marked the evolution of the current concept of pharmaceutical care. The keynote speaker, Douglas Hepler, argued that the incidence and cost of drug-related morbidity and mortality should lead to a dramatic change in the attitudes of pharmacists who were seeking a new professional mission to meet the expectations and needs of society. Hepler and Strand then provided their popular definition of pharmaceutical care, which described it as ‘the responsible provision of drug therapy for the purpose of achieving definite outcomes that improve the patient’s quality of life’ 4. This definition, which placed QoL in the core of the pharmaceutical
Assessment of quality of life in pharmaceutical care Describing pharmaceutical care as an outcomeoriented practice means that the ability to assess outcomes should be considered an essential part of its implementation. Where neither cure nor prevention is possible in chronic conditions, the extent to which healthcare interventions, including pharmaceutical care provision, improve QoL becomes the desired and most realistic outcome. As a result, QoL measures, which assess subjective components of health, have become widely available. Because improving the patient’s QoL, and sustaining that improvement, represents the desired outcome for the pharmaceutical care practitioner, evaluating changes in QoL should be considered an essential component of monitoring the overall effectiveness of pharmaceutical care 5. Clinical measures, such as blood pressure and pulmonary function, should be considered surrogate endpoints for what we really want to achieve: the effect of treatment on patients’ quality of lives. However, perception of health by the individual can also have bearing on QoL, and is considered an outcome worthy of consideration 6. It is hence anticipated that in their pharmaceutical care practice, pharmacists start to use, or start to learn to use, outcome measurement tools that enable them to monitor those areas of health which are affected by disease, or by the provision of pharmaceutical care, in a more scientific and ‘quantifiable’ manner. Such a skill will complement the present emphasis on evidencebased practice, and provide the pharmacist with an opportunity to present strong evidence for the worth of their professional interventions.
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Measuring quality of life: practical issues QoL analysis is helpful for investigating the social, emotional and physical effects of treatments and disease processes on daily living from the perspective of the patient. The last two decades have witnessed a great deal of progress in constructing measures, or instruments, that are used to measure aspects of QoL with impressive accuracy and precision. Most QoL instruments are based on the development of questionnaires that has the ability of reliably and validly measure the level of disability in different domains of an individual’s life as subjectively experienced by that individual. These questionnaires typically include questions (or items) about how the patients feel, and are associated with response options such as dichotomous yes–no, seven- or nine-point scales, or visual analogue scales. Responses to these questions are aggregated into domains or dimensions (such as physical or emotional function) that yield an overall score. This is a complex process that requires skill and resources. Fortunately, several well-validated questionnaires are available for use in the healthcare field. An excellent overview of the different types of outcome instruments and their characteristics was given by Tully and Cantrill 7.
Generic and disease-specific questionnaires The two main types of QoL instruments available are generic and disease-specific questionnaires. Generic questionnaires reflect the degree to which the full spectrum of health is affected by different diseases. They can be employed when patients have multiple chronic conditions or when there are adverse affects of drug therapy. Disease-specific questionnaires include only those elements that are important to a specific disease, and are more capable of detecting a subtle change in quality of life as a result of a treatment or an intervention. Table 1 lists some examples of each type of questionnaire, with their applications, strengths and weaknesses. There are also some population-specific questionnaires, that specifically assess QoL aspects of
children or the aged. They are not (yet) used very much in healthcare related research.
The place of QoL in pharmaceutical care practice: the reality A study in the United States showed that while three quarters of a sample of American community pharmacists expressed willingness to use QoL assessment tools in their practice, only about 53% were familiar with the concept of QoL, and less than 5% reported familiarity with formal QoL instruments 7. This trend is probably not limited to the United States, suggesting that, despite the importance of outcome monitoring in pharmaceutical care, the reality remains that humanistic outcome (e.g., QoL) is still perceived as a vague end-point that lacks defined or practicable methods for measurement. This also means that there is an unfilled role for pharmacists in the assessment and monitoring of QoL as part of the practice of pharmaceutical care. However, measuring statistically significant changes in QoL as a result of pharmaceutical care provision is difficult in practice, and can sometimes provide disappointing results. A recent randomised controlled trial published in JAMA assessed the effectiveness of a pharmaceutical care program for patients with asthma or chronic obstructive pulmonary disease (COPD) and provided evidence of only little benefit over that gained by peak expiratory flow rate (PEFR) monitoring alone. The findings also questioned whether patient outcomes are enhanced by effective pharmacist-patient interactions 16. This study measured QoL using an asthma-specific instrument (the AQLQ), which could be considered sensitive enough to detect longitudinal change in QoL should that change exist 8. The authors described several limitations in their study that might have contributed to the poor implementation of the program, but one issue worthy of addressing, but was not mentioned, was assigning pharmacists to the pharmaceutical care group. Pharmaceutical care is a practice that requires a great deal of interest and commitment. Those pharmacists providing it in real life have
Table 1 Examples of quality of life measurements
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Measure
Example
Generic
– – – –
Diseasespecific
– The Asthma Quality of Life Questionnaire 8 – Arthritis Impact Measurement Scale 16 – Inflammatory Bowel Disease Questionnaire 17
Application
Wide variety of Short Form 36 (SF-36) 12 populations The EuroQOL 13 Nottingham Health Profile 14 The Sickness Impact Profile (SIP) 15
Strengths
Weaknesses
• Do not focus on • Usually a single area of interest instrument • May not be re• Established relisponsive ability and validity • Allow comparison between conditions or interventions
Focus on problems • Clinically sensible • Do not allow comparison beassociated with spe- • May be more retween conditions sponsive than cific diseases, • Limited in terms generic instrupatient groups or of populations ments areas of function and conditions
surely chosen it as a professional direction, and are committed to it. One would question, therefore the validity of assigning a group to provide the service, and how that compares with real life situations in which the pharmacist chooses to become a pharmaceutical care provider. Interestingly, Schulz and colleagues conducted a controlled trial in which pharmacists were given the choice to join the intervention or the control group. Their study provided data suggesting improvement in asthma-related QoL domains of the AQLQ, and the mental health summary of the SF-36 9. A lesson learnt from the results of trials involving pharmaceutical care so far is that pharmaceutical care should be considered merely a tool, hence the results it provides depends on the hand using this tool. The analogy is that of a nice looking set of darts; however beautiful they might be, they still need a steady hand and a focussed mind to hit the bulls-eye. Because pharmaceutical care is an intuitively sensible practice, how effective it becomes would depend on a plethora of external factors (personal commitment, time, physical facilities, type and content of training program provided, and others). The absence of a QoL instrument specifically designed for use in pharmaceutical care could be another possible reasons for the difficulty in detecting improvement in QoL domains as a result of pharmaceutical care provision. The 2nd International Working Conference on Quality Issues in Pharmaceutical Care Research (2001), which was organised by the Pharmaceutical Care Network Europe (PCNE), conducted a workshop that addressed this issue on the basis that very little evidence existed to suggest that the implementation of pharmaceutical care results in improvement of QoL as measured by existing instruments 18. The participants assessed dimensions of QoL that they expect to change as a result of resolving drug related problems. They suggested that a QoL instrument suitable for use in pharmaceutical care should include three domains: the first is a physical domain, the second is a social domain (with social well-being sub-domain; a social-functioning sub-domain; and an energy and vitality sub-domain), and the third is psychological domain (with a cognitive and functioning sub-domain). This initiative of the PCNE working group had provided initial direction and made some progress towards defining domains in a QoL instrument suitable for use in pharmaceutical care. However, since then very little development has occurred, and as of yet, no final ‘product’ ready for use, or for piloting or validation, exists. As a result, pharmaceutical care providers have had few structured or validated methods to help them identify the areas of function affected by the medical conditions presenting to them, and several studies have supported the notion that existing generic QoL instruments might lack the specificity and the sensitivity required to express change as a result of applying pharmaceutical care. The choice of QoL instruments for use with pharmaceutical care can also contribute to the difficulty in detecting significant change over time. Volume et al. conducted a randomised controlled trial that compared several outcomes, including QoL (using the SF36) of patients after the provision of pharmaceutical care with those of patients who received traditional
pharmacy care 19. The results gave no clear evidence that pharmaceutical care affects patients’ QoL, and a recommendation was made that instruments more specific than the SF-36 may be needed to detect the differences. Similar findings were reported by Malone and colleagues, who recommended the use of more sensitive QoL instruments to measure a significant change 20. While both studies described used the SF36, it must be emphasised that the inability to measure change is probably not due to an inherit deficiency in the measurement properties of the SF-36. Generic QoL instruments, in general, are known to be less capable of detecting change over time. This is hardly surprising, since they are known to be less sensitive than disease-specific instruments in measuring ‘longitudinal’ change in QoL 21. They are therefore considered more powerful as discriminatory rather than evaluative tools, and their use is more in the context of cross-sectional comparisons, at specific points of time, than in longitudinal designs. A second possible reason for the failure in detecting measurable change relates to the nature of the intervention. Pharmaceutical care is largely a behavioural intervention, which can result in subtle changes in QoL domains that require a great deal of sensitivity in an instrument to detect. Indeed, interventions that aim to influence behaviour might require longer periods of time and several interactions with the service provider to be reflected in significant, and measurable, outcome changes 10. A purely pharmacological intervention, in comparison, can be invasive enough to result in clearer changes in life domains (specially in symptoms, role functioning and physical performance areas), and these can be reflected by the score changes of a less sensitive instrument. Would the utilisation of disease-specific instruments be potentially more useful in detecting change involving pharmaceutical care interventions provided by well-trained and committed pharmacists? On the basis of what we know of the psychometrics of QoL instruments, the use of disease-specific questionnaire in pharmaceutical care seems to be highly desirable in the light of their responsiveness and sensibility. Their use would assist the pharmacist to determine the impact of an intervention on the QoL of the patient, and to assist in better overall management of the patient. Nevertheless, there are important limitations to the sole reliance on disease-specific measures. One limitation is where general aspects of QoL, and not only those areas of QoL associated with a specific condition, are to be measured (such as when measuring the general health status of an elderly population, or of patients on polypharmacy). In these cases, a generic instrument might prove to be more relevant. In addition, while disease-specific measures may comprehensively sample all aspects of QoL associated with a specific illness and still be responsive, they are unlikely to address side effects that occur as a result of treatment. For example, the developers of the AQLQ ensured the inclusion of all areas of a patient’s life that are affected by asthma, but no mention was made of the adverse effects that can be associated with treatment and can reflect on the individual’s QoL (such as oral thrush or hoarseness of voice with inhaled corticosteroids). To make up for this deficiency, a separate checklist to document adverse effects could prove useful. Alternatively, a generic QoL could be administered
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along with the disease-specific questionnaire. However, in the latter case, the burden of responding to multiple questionnaires on the patient should be carefully considered and weighed against the gains expected. Finally there is the issue of the rationale for using QoL instruments with individual patients by practitioners in real life situations. In such situations where the practitioner is not necessarily interested in collecting data for research purposes, or in determining statistical significance of the changes observed, he or she would require an instrument that is able to detect change in an individual’s QoL over time, and thereby provide a method that guides his practice. An American College of Clinical Pharmacy (ACCP) Task Force on Ambulatory Care Clinical Pharmacy Practice published a White Paper in 1994 in which they proposed that pharmacists might be able to assess health outcomes, including objective and subjective measures (QoL), at baseline and prior to providing any specific intervention. After providing the intervention for a pre-determined period of time, the same data is collected again, and the impact of the intervention on the patient’s health outcomes is determined 11. We support this approach, and consider it a first step towards more rational and constructive use for QoL data in pharmaceutical care.
Conclusion We urge pharmacists providing pharmaceutical care to start adopting subjective health outcomes, specifically QoL measurements, in their practice. This is of special importance when dealing with chronic conditions, where a cure is not achievable, and the more realistic objective of treatment is an improvement in the functioning of the patient, both physically and psychosocially. It is essential that the validity of QoL instruments, as everyday practice tools, is evaluated and guidance is given to practitioners on exactly what a QoL instrument measures and what changes in a patient’s QoL measures actually mean. Luckily, there are a number of valid and easy to use generic and diseasespecific QoL instruments for utilisation in clinical practice (the Quality of Life Instruments Database of the Mapi Research Institute contains a long list with detailed information*). Until a universal QoL instrument is developed for use in pharmaceutical care, disease-specific instruments, complemented in some cases with generic instruments and other outcome measures where appropriate, could prove useful as screening tools for individual patient situations, and not necessarily in a research environment. This should provide the pharmacist with reasonable baseline scores reflecting different QoL domains, and the extent to which these domains are affected by disease. Subsequent measurements (separated by time intervals) could reflect score changes indicating improvement or deterioration in QoL. It * Building the Science of Quality of Life. Mapi Research Institute. Retrieved from http://www.mapi-research-inst.com/index02. htm on 5 November 2002.
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should be noted that these changes in scores should not be expected to have statistical significance, as the instruments are used as screening rather than research-oriented tools. While this proposed use of QoL measures seems logical and has the potential of assisting pharmacists providing pharmaceutical care, it has not yet been supported by empirical evidence. As such, research is needed in this area to show the usefulness and applicability of this approach.
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