A Framework for Generalizability in Palliative Care

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Journal of Pain and Symptom Management

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Special Article

A Framework for Generalizability in Palliative Care David C. Currow, MPH, FRACP, Jane L. Wheeler, MPH, Paul A. Glare, MM, FRACP, Stein Kaasa, MD, PhD, and Amy P. Abernethy, MD Department of Palliative and Supportive Services (D.C.C., A.P.A.), Flinders University, Adelaide, and Southern Adelaide Palliative Services (D.C.C., A.P.A.), Repatriation General Hospital, Daw Park, South Australia, Australia; Division of Medical Oncology (J.L.W., A.P.A.), Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA; Department of Medicine (P.A.G.), University of Sydney, and Palliative Care, Sydney Cancer Centre (P.A.G.), Royal Prince Alfred Hospital, Camperdown, Sydney, New South Wales, Australia; and Unit for Applied Clinical Research (S.K.), The Norwegian University for Science and Technology, and Palliative Medicine Unit (S.K.), Trondheim University Hospital, Trondheim, Norway

Abstract Palliative medicine has only recently joined the ranks of evidence-based medical subspecialties. Palliative medicine is a rapidly evolving field, which is quickly moving to redress its historical paucity of high-quality research evidence. This burgeoning evidence base can help support the application of evidence-based principles in palliative and hospice clinical care and service delivery. New knowledge is generally taken into practice relatively slowly by established practitioners. At present, the translation of evidence into palliative and hospice care clinical practice lags behind emerging research evidence in palliative care at even greater rates for three critical reasons: 1) the application of research results to specific clinical subpopulations is complicated by the heterogeneity of palliative care study subpopulations and by the lack of a recognized schema for describing populations or services; 2) definitional issues in service provision are, at best, confusing; and 3) fundamental research concepts (e.g., external validity, effect size, generalizability, applicability) are difficult to apply meaningfully in palliative care. This article provides a suggested framework for classifying palliative care research subpopulations and the clinical subpopulations to which the research findings are being applied to improve the ability of clinicians, health planners, and funders to interpret and apply palliative care research in real-world settings. The framework has five domains: patients and caregivers; health professionals; service issues; health and social policy; and research. J Pain Symptom Manage 2009;37:373e386. Ó 2009 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved. Key Words Palliative care, evidence-based medicine/evidence-based practice, generalizability, models of service provision, validity, end-of-life care/terminal care/hospice care

Address correspondence to: David C. Currow, MPH, FRACP, Flinders University, 700, Goodwood Road, Daw Park, South Australia 5041, Australia. E-mail: [email protected] Ó 2009 U.S. Cancer Pain Relief Committee Published by Elsevier Inc. All rights reserved.

Accepted for publication: April 3, 2008.

0885-3924/09/$esee front matter doi:10.1016/j.jpainsymman.2008.03.020

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Background In 2006, the field of palliative care passed a critical milestone in its effort to become a more effective contributor to evidence-based medicine (EBM) in the United States. In June, the Accreditation Council for Graduate Medical Education (ACGME) initiated the process of ACGME accreditation for Hospice and Palliative Medicine fellowship programs. In September, the American Board of Medical Specialties approved the creation of Hospice and Palliative Medicine as a subspecialty of 10 participating boards, including the American Boards of: Anesthesiology, Emergency Medicine, Family Medicine, Internal Medicine, Pediatrics, Physical Medicine and Rehabilitation, Psychiatry and Neurology, Radiology, Surgery, and Obstetrics and Gynecology (pending approval). This formal recognition by two of the most prominent and influential institutions in U.S. academic medicine will have influence on recognition of the specialty in other parts of the world. As palliative medicine is recognized as a subspecialty, it is timely also to adopt key standards of other medical specialties and subspecialties by: examining its methods and rationale for clinical decision-making; identifying obstacles to the translation of research evidence into clinical practice, especially generalizability;1 developing strategies for overcoming these obstacles and shortcomings; and updating its clinical and research practices to meet the standards of highest-quality EBM. In short, there is urgency to adopt the key tenets of EBM as a conscious process in palliative and hospice care.

What Research Concepts Do Palliative Medicine Clinicians Need to Understand to Generalize Research Findings into Practice? Evidence-based practice (EBP), the application of EBM principles and methods to daily clinical decision-making, encourages clinicians and health service planners to find the best evidence available to help them answer current questions. The core skills required for this process can be laid out as a series of steps: ask, find, appraise, act, and evaluate. Critical appraisal, at the center of this process, hinges on an understanding of several key concepts.2

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Internal Validity: Quality of study design that increases confidence in the ability to infer cause (the independent variable) and effect (on the dependent variable) in interventional studies. Effect Size: The magnitude of benefit attributed to an intervention, a construct that is independent of sample size. External Validity/Generalizability: The extent to which the findings of a study can be applied to another patient, population or setting of care. Applicability: The ability to apply the findings to a patient/group of patients in the broadest terms.3 Will this person react the same way to the intervention for the same net clinical benefit? Both generalizability and applicability require knowing the population (or patients) and the setting of the original study (a responsibility of the person reporting the research), and answering the question, ‘‘Would this individual patient have been eligible for the study whose results are being considered?’’ The issues being addressed in this article relate to generalizability.

The Problem: Why Is Generalizability of Palliative Care Research Any Different from Other Clinical Disciplines? Overview and Need The quality of palliative care will improve to the extent that palliative care research activities generate a body of evidence to support this newly emerging clinical subspecialty, and that clinicians employ EBM principles and methods in applying this evidence to their own practices. EBM requires: a high-quality body of research evidence; an agreed taxonomy for the processes that the research is describing; and that clinicians take a systematic approach to applying the evidence. Clinicians need to use critical appraisal skills to evaluate the evidence, apply the evidence appropriately to their clinical populations, and ultimately make clinically relevant decisions, to benefit the individual patient, based on the evidence. In translating evidence into practice, clinicians must determine whether the research findings from the study

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population can be generalized to apply to their particular clinical populations. At present, difficulties in this generalizing step may introduce bias, and even error, into the translation of palliative care research evidence.

Two Key Problems Intrinsically, there are two key problems in the chain of palliative-care-evidence-into-palliative-care-practice. There are differing definitions in terminology in palliative and hospice care around the world, and there is no framework for application of study results, given the very different patient populations in a specialty where only a fraction of eligible patients may be referred to specialist hospice/palliative care services (SHPCS), and that fraction is likely to differ from service to service and almost certainly from country to country. 1. Definitional issues limiting generalizability in palliative care: Palliative care, perhaps more than any other medical discipline, experiences problems in translating research evidence into practice. Clinical terminology itself lies at the root of the problem. For example, cardiology has achieved internal agreement on definitions for key constructs in their fields, such as ‘‘congestive heart failure,’’ ‘‘myocardial infarction,’’ ‘‘arrhythmia,’’ or ‘‘coronary care unit.’’ In palliative medicine, by contrast, definitions differ on fundamental terms. ‘‘Hospice,’’ for example, means ‘‘home care for patients with only a few weeks to live’’ on one side of the Atlantic, and ‘‘specialized in-patient care for weeks to months’’ on the other. Similar discrepancies exist for other basic concepts in palliative care, such as ‘‘end-of-life,’’ ‘‘terminal,’’ or ‘‘caregiver.’’ This lack of common language frustrates clinicians’ efforts to draw conclusions from the research literature and to apply that evidence to their local clinical setting. The lack of common terminology and absence of a framework to assess generalizability continues to hamper efforts to distill best practices from the quality evidence now being generated in the palliative care research literature. Ultimately, this limits the development of EBP and may be limiting the quality of care that can be offered to people at the end of life.

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2. Problems with defining intervention and target populations in palliative care: The heterogeneity of palliative care populations complicates efforts to generalize from one population to another. Palliative care populations present markedly different characteristics depending on country, region, and local settings. Because half of all patients with life-limiting illnesses access palliative care services, the total palliative care population contains a high degree of heterogeneity and includes a broad spread of diagnoses.4e7 The aggregate 50% referral rate of people with life-limiting illnesses exhibits wide local and national variation8,9 owing to the differences in health system structure, resources, and clinical relationships (Fig. 1).10,11 This inserts an additional step in the process of defining the study and population, and in understanding the target population to which the study’s findings will be applied (Fig. 1). Clinical subpopulations differ in life expectancy, functional status, and the prevalence, nature, and severity of comorbidities. Study populations differ because of variations in referral rates between physicians, and across continents. Diversity of populations in palliative care often makes applicability difficult to judge. A typical approach for determining applicability is to examine the study’s inclusion and exclusion criteria, and on that basis, to determine whether the patient (or population) in question would have been eligible for inclusion in the study. An alternative and less restrictive approach is to decide whether there is a compelling reason, based on the external validity of the study, that the study findings should not be applied to the individual (or population) in question. The study must also take account of any potential outcomes, harms, and costs that would be important to the particular individual or population.12 Other factors that may confound generalizability, specifically in referral-based palliative care practices, are outlined in Table 1. The net effects of these factors are that: the subpopulation seen by any individual palliative care service is a locally determined subset of the entire population with life-limiting illness (Fig. 1); research study populations have distinctive characteristics that may or may not match any given clinical subpopulation; and common

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Four step process for hospice / palliative care services (shared with other areas such as rehabilitation and psycho-geriatrics)

Three step process for identifying participants for most clinical studies

1.Acute myocardial infarction

100 of people referred to specialist cardiac services – minimal filtering

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Potential research participant with a condition / diagnosis of interest

1. End-stage non-small cell lung cancer

Filtering of potential participants because of variable referral to specialist services

2. Only a proportion (10 -60 ) of these patients will be referred to specialized hospice / palliative care services (SHPCS). If people with end-stage lung cancer are recruited to clinical studies in SHPCS, participation is ultimately dependent on local referral patterns to the SHPCS. Hence the cohort available to participate differs from service to service.

2. All people with the condition as potential participants

Able to participate in an appropriate study

3. Other eligibility criteria tested

Proceed with normal clinical trials processes

3. Only a percentage of potential participants identified from a far wider field of people with the index condition

4. Other eligibility criteria tested

Fig. 1. Access to specialist services for potential trial participation comparing a diagnosis-based referral (acute myocardial infarction) with a referral that is not primarily based on diagnosis nor prognosis (advanced non-small cell lung cancer).

terminology to define and compare palliative care populations is, as yet, nonexistent. A key challenge for, and one of the overarching purposes of, EBM is improving quality of care at a population level.13,14 In turn, population-level guidelines and best practices become meaningful only in their application in specific patient groups, or clinical subpopulations. Aggregated research evidence will support the development of these population-level best practices and clinical guidelines so that they can be translated to specific clinical subpopulations. The ability of a clinician to quickly and confidently decide whether or not a reported intervention will be beneficial for an individual patient is an ongoing and fundamental challenge of providing quality care in any clinical setting.

In addition to inhibiting the translation of research findings into practice, inability to rapidly and reproducibly generalize the results of palliative care research findings harms the future of palliative medicine in other important ways:  It limits service development, because palliative care programs are less able to complete for the limited health funds available.  It hinders the development of guidelines, quality outcome metrics, best practices, and other quality-improvement measures, because palliative care researchers and clinicians do not have common definitions for concepts like ‘‘best supportive care.’’  It thwarts efforts to allocate scarce resources to patients with greatest need.15,16

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Table 1 Factors Specifically Related to Palliative Care as a Referral-Based Specialty that May Affect Generalizability in Well-Executed Research Studies Factors

Examples

Even within a referral-based specialty, there are lower levels of referral for identified subpopulations with further variation from service to service.

People from culturally and linguistically diverse populations; people from lower socioeconomic strata; people with a noncancer, life-limiting illness; the elderly.6,7,49e52

Different health and social systems attribute differing values to the provision of supportive, palliative and end-of-life care.

Differing levels of funding and other resources directed to palliative care clinical service provision, education and research.

The large number of descriptive studies in the palliative care literature.46

Dependence on the proportion and characteristics of the local population referred to palliative care influences the participants recruited to the study and hence its generalizability (Table 4).

Randomized controlled trials (RCTs) in palliative care may have referral biases that limit generalizability unless the study population and its relationship to all referrals and all eligible referrals are described.

Well-designed RCTs with explicit inclusion and exclusion criteria can still only recruit participants referred to the service. Identical studies in different palliative care services may reach different conclusions because of the population differences in the people referred to these services (Table 5; Fig. 1).

Patients’ and caregivers’ needs are not determined by diagnosis nor prognosis in palliative care.16

Simple categorization by disease severity or estimated prognosis will not account for the threshold of needs-based referral that typifies palliative care, rehabilitation, and aspects of elder care.

A Solution: A Generalizability Framework that Describes Any Palliative Care Research Population and the Clinical Population to Which the Research Could be Applied The remainder of this article will suggest a framework for addressing problems related to generalizability: Would the population reported in the study be referred to the palliative care service to which the results are being applied? Would the person to whom the results are being applied have been referred to the clinical study being reported? In palliative care, generalizability could be facilitated by a framework that enables comparisons between palliative care populations by describing prospectively: 1) at the time the study is conceived by the researchers the subpopulation being studied; 2) as other clinicians read the study outcomes, the subpopulation to which the study’s findings will be applied. Until such a framework can be put in place, EBM-based practice in palliative care will remain flawed at best, and severely limited at worst, without a clearly shared, understood,

and readily applied framework to help clinicians generalize from research subpopulations to specific clinical subpopulations in other settings. The lack of common language for describing palliative care populations leaves the clinician without a tool to assess a research study’s generalizability, and to assess its applicability to his/her clinical population or specific patient. A first step in improving EB methodology in palliative medicine, therefore, is to articulate study domains that define, in a meaningful way, key aspects of the population and setting. These domains will help researchers to characterize their research and help clinicians to clarify the parameters of the study population/ setting, in addition to defining those of the clinical population/setting in which he/she might apply the findings. We propose five domains that help to describe palliative care populations and need to be applied at the time that researchers are designing their study (so that relevant data can be collected), and used by clinicians so that they can most effectively apply the findings of the research to their clinical setting and the group of patients concerned: patients and caregivers; professional; service; national/state health and social policy; and research factors.

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Domain 1: Patient and Caregiver Factors Patient Demographic Factors. Basic demographics include: eage (median, mean, and range) and gender;17,18 elocally relevant racial and ethnic diversity; eindices of social support, including marital status, accommodation setting, and living arrangements; and elocal socioeconomic indices, such as median income, given the known associations with health status, health outcomes, and caregiver availability.17,19e21 Patient Clinical Factors. Clinical factors at the time of referral include: eprincipal life-limiting illness and extent of disease; enumber and nature of active comorbidities; and eglobal indices, such as performance status,22 phase of palliative care,23 and time from referral to death (median, mean, and range).24e26 Caregiver Factors. The number of people with an identified caregiver is an important indicator in palliative care because of its impact on place of care.19,27 Caregiver issues are complex but important in understanding key differences in patient populations.28,29 Relevant factors to be considered in this domain include: epercentage of population with no identifiable caregiver; eavailability of caregiver living in the same household; epercentage of caregivers still working full-time; epredominant relationships of caregivers to care recipients; and epercentage of caregivers with comorbidities that interfere with care.

Domain 2: Professional Factors The first factor in considering the professional parameters of the palliative care population in question is the status accorded to palliative care in the country reporting the study. Is palliative care (and its discipline-specific branches in nursing, medicine, and allied health) recognized as a distinct area of specialty practice?30,31 Such recognition may

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indicate the role of palliative care within the broader health sector. Where palliative care is well-recognized, a higher level of training and more advanced skill base of palliative care service personnel may influence referral patterns to the service and the way the service grows and develops as it interacts with other clinical services. Without this recognition, clinicians who are providing care to people with life-limiting illnesses are likely to care for a very small number of such patients relative to their overall workload.32,33 Professional factors that may impact the palliative care population include: eEducation of primary care providers and referring specialist teams. The preparation of this level of providers (those who refer patients to palliative care) will influence the palliative care population. Here, a relevant objective measure is whether continuing professional development opportunities are available and taken up by practitioners whose substantive work is not in palliative care. eEducation of palliative care service providers. The composition of the palliative care population will be influenced by the availability of nursing, medical, and allied health providers who have taken up palliative care as their predominant clinical training. This may also reflect in the nature and extent of subsequent professional development activities for palliative care specialists and researchers.

Domain 3: Service Factors Efforts currently underway to generate more structured frameworks for service provision and for access to palliative care may serve to make describing this domain easier.11,34e37 We cannot expect the impact of these efforts to be universal, and even with such frameworks in place, there will still remain the need to compare and contrast subpopulations referred to palliative hospice care services locally. Referral patterns, and hence palliative care subpopulations, may vary because of factors including: Local Palliative Care Model of Service Delivery (Primary or Consultative). Is the service one that econsults other clinicians, or one that provides all the direct care to people

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with a life-limiting illness, or a mixture of both?; and eis predominantly hospital-based, community-based, hospice, or a regional service regardless of where the person is situated?38 This characterization will help to shape fundamentally the population included in any palliative care study. For example, a palliative care team based only in a tertiary hospital will have a patient mix reflective of the clinical acuity of the needs of hospitalized patients, whereas a community team may reflect a more ambulant population. Access to Services. Ease or barriers of access to palliative and hospice care services will play a role in determining the composition of palliative care subpopulations. Relevant questions include: eWhat is required to initiate access to the palliative care service? eCan patients self-refer; can a family refer; or is referral restricted to health professionals? eWhat percentage of referrals comes from primary care, compared with emergency departments or hospital consultation teams? eAre outpatient clinic services available to palliative patients? Admission and Discharge Policy. The admission and discharge policies for the local palliative care program will have an impact on that program’s population. Relevant considerations are: whether the admission criteria are based predominantly around diagnosis (cancer, noncancer), prognosis, or complexity of needs.10,15,16,24,39 If criteria are predominantly prognosis-based, then length of stay for patients in the service may be limited to more terminal periods, whereas in a needs-based system, length of stay may cover a longer time period for people with more complex needs.

Domain 4: Health and Social Policy Factors Model of Health System. Health systems influence a person’s ability and likelihood of accessing specialized palliative care services. For example, the United States bases its model of health care delivery on principles of economic liberalism and the laws of the free market

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system, with universal coverage of those over 65 years or people with predefined needs. In Western Europe, Canada, and Australia, health care policies are framed in accordance with a social-democratic vision, which attempts to allocate resources in a manner that values societal equity. Variations on these two models can be found throughout the world. Other factors that may influence the health system include ewhether there is a single source of funding or multiple sources for the same episode of care; ewhether the health system has established gatekeeper roles (limiting access to specialists through general practitioners/family physicians, for example); ethe involvement of government in setting or monitoring the availability or costs of medical care or medical insurance; ePer-diem payments, such as the 1982initiated U.S. Medicare hospice per-diem payment40,41 or other fee-for-service models when compared with payments for whole episodes of care. For example, fee-for-service settings may potentially delay referral to palliative services, whereas salaried clinical staff may be more likely to refer at an earlier phase of a person’s life-limiting illness; eany reliance on funding clinical services from charitable donations (where individual donor issues may influence service provision); or ecapped benefits or payments for services. The impact of these economic and health care delivery factors on aspects of palliative care, such as referral and continuity of care, should not be underestimated.42,43 For caregivers, questions in this domain include whether there is support (government, private payer, insurance) for caregivers. Do workplace provisions allow for caregivers to be provided with leave to take on the caregiving role?

Domain 5: Research Factors Questions of importance here include whether the reported results were derived from analysis of a primary data set, from

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secondary analysis of another data set, or from analysis of data not collected for research. Were the outcome measures used in the research properly validated for use in palliative care populations (because if not, potentially both the internal and the external validity of palliative care research may be compromised).44 Use of widely validated, reliable, and agreed measurement tools will help readers more easily compare studies, better evaluate outcomes, and adapt those findings to clinical practice.45

Applying the Model: Suggestions for Putting the Generalizability Framework into Practice There are two levels of data complexity in the domains proposed. The first of these deals with basic descriptors in each domain (Table 2). An extended version (Table 3) provides more detail in each domain. Although largely arbitrary at this time, the distinction between ‘‘core’’ and ‘‘optional’’ elements relates to the highest likelihood that a data item will influence generalizability, and also that the data are likely to be already collected or are very easily accessible. Future work will include determining the individual factors that influence the generalizability of palliative care research the most. Not all domains have the same relevance to all study designs. For all nonrandomized trials of direct patient care, such as case series or cohort studies, all five domains are crucial (Table 4). For interventions which include professional skills, such as counseling or behavior modification, Domains 2 and 5 have special importance. For health service delivery studies, Domains 2, 3, 4 and 5 will greatly influence generalizability. For evaluation of caregiver support processes, even in a randomized controlled trial (RCT), all five domains will need to be carefully considered (Table 5). A central step in practicing EBM is critical appraisal of the evidence. To perform this step in Palliative Medicine, as in any medical discipline, clinicians must employ a systematic approach to the evidence. One key element of this systematic approach is the use of an agreed language with agreed definitions, which ensures that all readers of the same

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literature will reach similar conclusions from a given research study. The proposed generalizability framework provides a lexicon for defining palliative care populations, and for making sense of research findings. Promotion of the proposed framework represents an educational step necessary to enable palliative care researchers and clinicians to ‘‘speak the same language,’’ and thus to appropriately move evidence into practice and policy. The authors suggest that the researchers should familiarize themselves with the generalizability framework using a detailed version (Tables 2 and 3), and that the field should adopt a simplified and convenient version (Table 2) for frequent and efficient comparison of palliative care populations by researchers submitting their research for publication and for clinicians seeking to apply the findings. By understanding and employing the proposed domains, researchers will be abledefficiently, using standardized termsdto describe their research cohorts and settings; clinicians will be able to quickly identify the research population’s similarities to, and differences with, the clinical population to whom they might apply the findings. The clinician reading the research will be able to describe his/ her local service and the people referred to it using the same parameters that the researcher used to describe the study population. The framework thus elicits a simple thumbnail sketch that allows key characteristics to be captured, and establishes a common language to describe palliative care research and to better apply its findings in other services and settings. Ideally, all studies in palliative care in the literature should report one line for each domain, to help readers apply the study findings to their own palliative care setting. This standardized reporting of study parameters, even in a check-box format, will improve clinicians’ ability to identify studies that can be more easily generalized to their own setting. This would allow every clinician and service to use the generalizability framework to profile their population in each of the five domains, compare their profile to that of study populations, and translate research knowledge to their local setting with more confidence. Why are these data not always included in scientific papers from hospice or palliative care research? Although this will need to be explored

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Table 2 Suggested Core Factors that May Affect Referral Patterns to Specialized Palliative Care Services, Referral to Their Studies, and Generalizability of Their Research Findings

Factors Domain 1: Patient and Caregiver

Suggested Core Data Items Patient factors

Patients’ clinical issues

Caregiver issues

Example Data Fields Age Gender Service socioeconomic indices (median income compared with national average, work force participation rates) Locally relevant racial or ethnic issues compared with population served Primary life-limiting illnesses Performance status on referral Phase of illness Time from referral to death (days) Percentage of people with no identifiable caregiver

Example Output for People at the Time of Referral Mean age, median age 54% female Median income covered by the service/median income of the country 9% of people referred had an Hispanic background compared with 13% of the region’s population 81% have cancer as their primary life-limiting illness Median performance status AKPS 60 Median phase 2 Mean 117; median 43 7% of people referred

Domain 2: Professional

Training in SHPC care as a specialty

Are nursing, medicine, and allied health professionals recognized as being in specialist SHPC clinical practice?

Subspecialty recognitiondyes

Domain 3: Service

Local SHPC model of service delivery

Is the service mainly consultative (supporting primary health professionals and other specialists), a primary care service, or a hybrid? Is the service hospitalbased, community-based, or regional? Is access to the SHPC service defined by diagnosis (cancer/ noncancer), prognosis, or complexitiy of needs?

Consultative service

Admission and discharge policy

Regional Needs-based admission to the service

Domain 4: Health and Social Policy

Health systems’ funding mechanism

Is the health system predominantly user-pays or is there some form of universal health service?

Universal health coverage

Domain 5: Research

Outcome measures

Are the outcome measures used in reporting research validated for a palliative care population?

Yes/no (for each measure)

AKPS ¼ Australian-modified Karnofsky Performance Status; SHPC ¼ Specialist Hospice/Palliative Care.

further, reasons could include that: authors assume that the factors pertaining to the setting in which the study is carried out pertain to all services; authors assume that readers know all these parameters; or that authors do not yet appreciate the importance of such a data set if

a referral-based specialty is going to ensure the optimal application of evidence-based care. Even if this generalizability framework were to be widely adopted, there remain challenges, including how to improve the applicability of palliative care research and to define the net clinical

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Table 3 Suggested Optional Factors that May Affect Referral Patterns to Specialized Palliative Care Services, Referral to Their Studies, and Generalizability of Their Research Findings Factors Domain 1: Patient and Caregiver

Suggested Fields

Example Data Fields at the Time of Referral

Patient demographics

Accommodation available to clients (owner occupier, rented). Marital status of people referred to the service Documented extent of disease Active comorbid illnesses Preferred place of care. Percentage with established cachexia at the time of referral Availability of caregiver living in the same household Percentage of caregivers still working full-time Predominant relationships of caregivers to care recipients. Percentage of caregivers with significant comorbidities

Patients’ clinical issues

Caregiver factors

Domain 2: Professional

Education of primary care/ referring teams Disciplines in SHPCS Ongoing education for SHPCS

Domain 3: Service

Service relationships with other providers

Are there formally negotiated relationships with (1) Other service providers (2) Referring units? Was the service planned de novo or has it evolved? What is required to initiate access to the palliative care service? (self-referral/family referral, health professional only) What percentages of referrals are from primary care/emergency departments or hospital consultation teams? Are there outpatient clinics available? Percentage of patients who are discharged from the service other than through death Who does the initial clinical assessment on referral? (nurse, nurse/doctor, nurse/ doctor/social worker) What quality improvement processes are in place in the service?

SHPCS evolution Accessing services

Discharge policy Clinical assessment Quality processes Domain 4: Health and Social Policy

Models of primary health care Caregiver support

Domain 5: Research

Intervention Data source

Continuing professional development opportunities are available to practitioners whose substantive work is not in palliative care Availability of nursing, medical, and allied health disciplines with palliative care as their predominant clinical practice Are there ongoing professional development opportunities, such as journal club, for the specialist clinical team?

Is there a primary care system universally available? Is there direct access to SPCS or do primary carers act as gatekeepers? Is there government support for caregivers (including financial support for them to leave the workplace to provide care)? Are there workplace provisions for caregiver leave? Are there unique local issues that frame the interventions used? Results are an analysis of primary data set? or Results are a secondary analysis of another data set? or Results are an analysis of data not collected for research?

SHPCS¼Specialist Hospice/Palliative Care Services.

benefit likely to accrue to an individual patient as a result of research findings in a better way. Are there costs (including staff time) associated with the proposed framework? Any cost is

likely to be minimal especially for ‘‘core’’ items. In Domain 1 (Patient and Caregiver Factors), data will already be collected in most clinical studies. Issues such as the percentage

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Table 4 Core Domains Highlighting Differences in Study Populations and Services on Referral (Identical Cohort Studies) Factors

Study Population 1

Study Population 2

Domain 1: Patient and Caregiver

Mean age: 74 years Median income: AU$54,000 2% from CALD backgrounds 14% of caregivers working 64% have active comorbid disease Median AKPS 50 Median time from referral to death: seven weeks

Mean age: 68 years Median income: AU$46,000 16% from CALD backgrounds 48% of caregivers working 22% have active comorbid disease Median AKPS 70 Median time from referral to death: 22 weeks

Domain 2: Professional

Primary care providers working part-time in palliative care with no formal training

Full-time vocationally trained palliative care health professionals in a health system that recognizes the specialty

Domain 3: Service

Prognosis-based referrals in a primary care model

Needs-based referrals to an interdisciplinary team sharing care with primary clinicians

Domain 4: Health and Social Policy

Fee-for-service payments for all services

Salaried palliative service staff

Domain 5: Research

Validated for a palliative care population

Summary of example patient

Late referral to a primary palliative care service of people with limited life expectancy and very poor level of function

Example Studies

Case series of 30 consecutive patients reflecting the use of medication X for difficult to control pain.

Participant characteristics

20% of referrals eligible for study Improved pain control for 70% of participants

5% of referrals eligible Improved pain control for 40% of participants

Withdrawal and side effects

20% withdraw because of nausea and vomiting

Conclusions

Good analgesia if nausea and vomiting can be controlled

5% withdrew due to nausea and vomiting (and 20% started on medications for nausea and vomiting) Some benefit in refractory pain but well tolerated

Contrast between study conclusions

In Group 1, given resource limitations, one may not be treating truly refractory paindthese people simply have untreated pain because of late referral and poor resources. In Group 2, an efficacy study has been donedhow the medication benefits and burdens patients whose analgesia has already been optimized before the introduction of medication X

Early referral of people to a specialist team with better level of function in a social setting that creates more complex needs

CALD ¼ culturally and linguistically diverse; AKPS ¼ Australian-modified Karnofsky Performance Status.

of people without an identifiable caregiver may well be on locally held data bases, and if not, are an important service-planning tool. Socioeconomic status and specific populations of need may be updated every three or five years for any service. Domain 2 (Professional Issues) and Domain 4 (Health and Social Policy) are measured at a state or national level and would only need to be updated as legislation or processes changed. Domain 3 (Service Issues) are local but change slowly, limiting the impost on clinical or research staff. Domain 5 (Research Issues) are dealt with ideally in the design phase of a study and should be reported in ‘‘Methods.’’ Optional fields may take more work, but if it will add to the uptake of research findings, such an investment may be justified. This needs to be confirmed in prospective work.

Future Directions As any addition to standard reporting practice, this generalizability framework will itself be the focus of future research, and will need to be iteratively validated and refined as:  experience with the framework generates data that can be used to better define ‘‘core’’ and ‘‘optional’’ items, and to weight their relative impact;  use of the model for different study designs enables evaluation of the relative importance of each domain and the elements in the domain for each study type;  palliative care service delivery and research continues to evolve in resourcerich and resource-poor countries around the world; and

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Table 5 Core Domains Highlighting Differences in Study Populations and Services on Referral (Identical RCTs Conducted) Factors

Study Population 1

Study Population 2

Domain 1: Patient and Caregiver

Mean age: 74 years Median income: AU$54,000 2% from CALD backgrounds 14% of caregivers working 64% have active comorbid disease Median AKPS 50 Median time from referral to death: seven weeks

Mean age: 68 years Median income: AU$46,000 16% from CALD backgrounds 48% of caregivers working 22% have active comorbid disease Median AKPS 70 Median time from referral to death: 22 weeks

Domain 2: Professional

Primary care providers working part-time in palliative care with no formal training

Full-time vocationally trained palliative care health professionals in a health system that recognizes the specialty

Domain 3: Service

Prognosis-based referrals in a primary care model

Needs-based referrals to an interdisciplinary team sharing care with primary clinicians

Domain 4: Health and Social Policy Domain 5: Research

Fee-for-service payments for all services

Fee-for-service payments for all services

Summary of example patient

Late referral to a primary palliative care service of people with limited life expectancy and very poor level of function

Example Studies

50 patients enrolled in adequately powered placebo-controlled, double-blinded study to determine a 10% change in a VAS at one week in dyspnea from medication Y.

Validated for a palliative care population Early referral of people to a specialist team with better level of function in a social setting that creates more complex needs

VAS drops by 25 mm (50%) in the intervention arm 5% withdrawal in study arm because of falls

VAS drops by 15 mm (30%) in the intervention arm 60% withdrawal rate due to somnolence

Conclusions

Good medication for dyspnea, but care required in frail patients

Medication with a significant side effect profile in a large number of people who were otherwise functioning quite well

Contrast between study conclusions

Study population 1 is frail and is already starting to fail systemically; so somnolence is not noted. Instead, falls become the manifestation of medication Y’s sedating effects. The higher response in population 1 is because of sedating effects not the relief of dyspnea per se. Study population 2 has a better functioning population with optimally treated reversible causes of dyspnea who do not tolerate even mild sedation

CALD, culturally and linguistically diverse; AKPS, Australian-modified Karnofsky Performance Status; VAS, visual analog scale.

 models of care become more standardized around complexity of the needs of the person with the life-limiting illness (rather than diagnosis or prognosis). Immediate work is to analyze how these domains are currently reflected in the studies that are being reported in the palliative care literature. Such an analysis would need to be stratified for the study design and will also allow subsequent analysis of the framework. There is urgency in applying the work from this model, given major new national and international initiatives in palliative care clinical research.46e48 These significant projects, which will contribute so strongly to EBP, need to include in their data-collection design the five domains in order to optimize the

ability of clinicians to apply most effectively the results in daily practice.

References 1. Abernethy AP, Currow DC. Culture and financing influence palliative care services, study populations, and generalizabiliy of research findings [letter]. J Palliat Med 2008;11(2):146. 2. Craig JC, Irwig LM, Stockler MR. Evidence based medicine: useful tools for decision making. Med J Aust 2001;174:248e253. 3. Jordhoy MS, Saltvedt I, Fayers P, et al. Which cancer patients die in nursing homes? Quality of life, medical and sociodemographic characteristics. Palliat Med 2003;17:433e444.

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4. Franks PJ, Salisbury C, Bosanquet N, et al. The level of need for palliative care: a systematic review of the literature. Palliat Med 2000;14:93e104. 5. Gott MC, Ahmedzai SH, Wood C. How many inpatients at an acute hospital have palliative care needs? Comparing the perspectives of medical and nursing staff. Palliat Med 2001;15:451e460. 6. Currow DC, Abernethy AP, Fazekas BS. Palliative needs of whole populations: a comprehensive population approach to determining need. Palliat Med 2004;18:239e247. 7. Rosenwax LK, McNamara B, Blackmore AM, Holman CD. Estimating the size of a potential palliative care population. Palliat Med 2005;19:556e562. 8. Addington-Hall J, Altmann D, McCarthy M. Which terminally ill cancer patients receive hospice in-patient care? Soc Sci Med 1998;46:1011e1016. 9. Bestall JC, Ahmed N, Ahmedzai SH, et al. Access and referral to specialist palliative care: patients’ and professionals’ experiences. Int J Palliat Nurs 2004;10:381e389.

385

19. Grande GE, Addington-Hall JM, Todd CJ. Place of death and access to home care services: are certain patient groups at a disadvantage? Soc Sci Med 1998;47:565e579. 20. Higginson IJ, Jarman B, Astin P, Dolan S. Do social factors affect where patients die: an analysis of 10 years of cancer deaths in England. J Public Health Med 1999;21:22e28. 21. Gibson R. Palliative care for the poor and disenfranchised: a view from the Robert Wood Johnson Foundation. J R Soc Med 2001;94:486e489. 22. Abernethy AP, Shelby-James TM, Fazekas BS, Woods D, Currow DC. The Australian-modified Karnofsky Performance Status (AKPS) scale: a revised scale for contemporary palliative care clinical practice. BMC Palliat Care 2005;4:7. 23. Eagar K, Green J, Gordon R. An Australian casemix classification for palliative care: technical development and results. Palliat Med 2004;18:217e226.

10. Anon. The national palliative care census. Canberra: Palliative Care Australia, 1999.

24. Christakis NA, Iwashyna TJ. Impact of individual and market factors on the timing of initiation of hospice terminal care. Med Care 2000;38: 528e541.

11. Currow DC, Nightingale E. Palliative service provision in Australia e planning resources. Med J Aust 2003;179:S23eS25.

25. Lamont EB, Christakis NA. Physician factors in the timing of cancer patient referral to hospice palliative care. Cancer 2002;94:2733e2737.

12. National Health and Medical Research Council. How to use the evidence: assessment and application of scientific evidence. Canberra: Commonwealth of Australia, 2000. NHMRC.

26. Coventry PA, Grande GE, Richards DA, Todd CJ. Prediction of appropriate timing of palliative care for older adults with non-malignant life-threatening disease: a systematic review. Age Ageing 2005;34:218e227.

13. Bakitas MA, Lyons KD, Dixon J, Ahles TA. Palliative care program effectiveness research: developing rigor in sampling design, conduct, and reporting. J Pain Symptom Manage 2006;31: 270e284. 14. Borgsteede SD, Deliens L, Francke AL, et al. Defining the patient population: one of the problems for palliative care research. Palliat Med 2006;20: 63e68. 15. Higginson IJ, Addington-Hall JM. Palliative care needs to be provided on basis of need rather than diagnosis [letter]. BMJ 1999;318:123. 16. Lidstone V, Butters E, Seed PT, et al. Symptoms and concerns amongst cancer outpatients: identifying the need for specialist palliative care. Palliat Med 2003;17:588e595. 17. Guyatt GH, Sackett DL, Cook DJ. Users’ guides to the medical literature. II. How to use an article about therapy or prevention. B. What were the results and will they help me in caring for my patients? Evidence-Based Medicine Working Group. J Am Med Assoc 1994;271(1):59e63. 18. Grande GE, Farquhar MC, Barclay SI, Todd CJ. The influence of patient and carer age in access to palliative care services. Age Ageing 2006;35: 267e273.

27. Maida V. Factors that promote success in home palliative care: a study of a large suburban palliative care practice. J Palliat Care 2002;18:282e286. 28. Mangan PA, Taylor KL, Yabroff KR, Fleming DA, Ingham JM. Caregiving near the end of life: unmet needs and potential solutions. Palliat Support Care 2003;1:247e259. 29. Harding R, Higginson IJ. What is the best way to help caregivers in cancer and palliative care? A systematic literature review of interventions and their effectiveness. J Palliat Care 2002;18:275e281. 30. Doyle D. Palliative medicine training for physicians. J Neurol 1997;244:S26eS29. 31. Glare PA, Auret KA, Aggarwal G, et al. The interface between palliative medicine and specialists in acute care hospitals: boundaries, bridges and challenges. Med J Aust 2003;179:S29eS31. 32. Shipman C, Addington-Hall J, Barclay S, et al. How and why do GPs use specialist palliative care services? Palliat Med 2002;16:241e246. 33. Barclay S, Wyatt P, Shore S, et al. Caring for the dying: how well prepared are general practitioners? A questionnaire study in Wales. Palliat Med 2003;17: 27e39.

386

Currow et al.

Vol. 37 No. 3 March 2009

34. Jordhoy MS, Fayers P, Saltnes T, et al. A palliative-care intervention and death at home: a cluster randomised trial. Lancet 2000;356:888e893.

43. Dumont I, Dumont S, Turgeon J. Continuity of care for advanced cancer patients. J Palliat Care 2005;21(1):49e56.

35. National Consensus Project. Clinical practice guidelines for quality palliative care. Brooklyn, NY: National Consensus Project for Quality Palliative Care, 2004.

44. Hølen HC, Hjermstad MJ, Loge JH, et al. Pain assessment tools: is the content appropriate for use in palliative care? J Pain Symptom Manage 2006;32(6):567e580.

36. Ahmedzai SH, Costa A, Blengini C, et al. A new international framework for palliative care. Eur J Cancer 2004;40:2192e2200.

45. Morrison RS. Palliative care outcomes research: the next steps. J Palliat Med 2005;8:13e16.

37. Thomas R, Richardson A. The NICE guidance on supportive and palliative caredimplications for oncology teams. Clin Oncol (R Coll Radiol) 2004; 16:420e424. 38. Glare PA, Virik K. Can we do better in endof-life care? The mixed management model and palliative care. Med J Aust 2001;175:530e533. 39. Christakis NA, Escarce JJ. Survival of Medicare patients after enrolment in hospice programs. N Eng J Med 1996;335:172e178. 40. Miller SC, Mor V, Coppola K, et al. The Medicare hospice benefit’s influence on dying in nursing homes. J Palliat Med 1998;1:367e376. 41. Pyenson B, Connor S, Fitch K, Kinzbrunner B. Medicare in cost matched hospice and non-hospice cohorts. J Pain Symptom Manage 2004;28:200e210. 42. Passik SD, Ruggles C, Brown G, et al. Is there a model for demonstrating a beneficial financial impact of initiating a palliative care program by an existing hospice program? Palliat Support Care 2004; 2:419e423.

46. Kaasa S, de Conno F. Palliative care research. Eur J Cancer 2001;37:153e159. 47. Gelfman LP, Morrison RS. Research funding for palliative medicine. J Palliat Med 2008;11(1):36e43. 48. Rowett D, Ravenscroft PJ, Hardy J, Currow DC. Using national health policies to improve access to palliative care medications in the community. J Pain Symptom Manage 2009;37:395e402. 49. Rhodes RL, Teno JM, Welch LC. Access to hospice for African Americans: are they informed about the option of hospice? J Palliat Med 2006;9: 268e272. 50. McGrath P, Vun M, McLeod L. Needs and experiences of non-English-speaking hospice patients and families in an English-speaking country. Am J Hosp Palliat Care 2001;18:305e312. 51. Fried O. Providing palliative care for Aboriginal patients. Aust Fam Physician 2000;29:1035e1038. 52. Murtagh FE, Preston M, Higginson I. Patterns of dying: palliative care for non-malignant disease. Clin Med 2004;4:39e44.