Developing a dementia-specific preference--based quality of life measure (AD-5D) in Australia: a valuation study protocol

A scoping review to create a framework for the steps in developing condition-specific preference-based instruments de novo or from an existing non-preference-based instrument: use of item response theory or Rasch analysis

BACKGROUND

There is no widely accepted framework to guide the development of condition-specific preference-based instruments (CSPBIs) that includes both de novo and from existing non-preference-based instruments. The purpose of this study was to address this gap by reviewing the published literature on CSPBIs, with particular attention to the application of item response theory (IRT) and Rasch analysis in their development.

METHODS

A scoping review of the literature covering the concepts of all phases of CSPBI development and evaluation was performed from MEDLINE, Embase, PsychInfo, CINAHL, and the Cochrane Library, from inception to December 30, 2022.

RESULTS

The titles and abstracts of 1,967 unique references were reviewed. After retrieving and reviewing 154 full-text articles, data were extracted from 109 articles, representing 41 CSPBIs covering 21 diseases or conditions. The development of CSPBIs was conceptualized as a 15-step framework, covering four phases: 1) develop initial questionnaire items (when no suitable non-preference-based instrument exists), 2) establish the dimensional structure, 3) reduce items per dimension, 4) value and model health state utilities. Thirty-nine instruments used a type of Rasch model and two instruments used IRT models in phase 3.

CONCLUSION

We present an expanded framework that outlines the development of CSPBIs, both from existing non-preference-based instruments and de novo when no suitable non-preference-based instrument exists, using IRT and Rasch analysis. For items that fit the Rasch model, developers selected one item per dimension and explored item response level reduction. This framework will guide researchers who are developing or assessing CSPBIs.

Preferences for deprescribing antihypertensive medications amongst clinicians, carers and people living with dementia: a discrete choice experiment

BACKGROUND

Optimal management of hypertension in people with dementia may involve deprescribing antihypertensives. Understanding differing treatment priorities is important to enable patient-centred care. This study explored preferences for antihypertensive deprescribing amongst people living with dementia, carers and clinicians.

METHODS

Discrete choice experiments (DCEs) are a stated preference survey method, underpinned by economic theory. A DCE was conducted, and respondents completed 12 labelled choice-questions, each presenting a status quo (continuing antihypertensives) and antihypertensive deprescribing option. The questions included six attributes, including pill burden, and event risks for stroke, myocardial infarction, increased blood pressure, cognitive decline, falls.

RESULTS

Overall, 112 respondents (33 carers, 19 people living with dementia, and 60 clinicians) completed the survey. For people with dementia, lower pill burden increased preferences for deprescribing (odds ratio (OR) 1.95, 95% confidence interval (95% CI) 1.08-3.52). Increased stroke risk (for each additional person out of 100 having a stroke) decreased the likelihood of deprescribing for geriatricians (OR 0.71, 95% CI 0.55-0.92) and non-geriatrician clinicians (OR 0.62, 95% CI 0.45-0.86), and carers (OR 0.71, 95% CI 0.58-0.88). Increased myocardial infarction risk decreased preferences for deprescribing for non-geriatricians (OR 0.81, 95% CI 0.69-0.95) and carers (OR 0.84, 95% CI 0.73-0.98). Avoiding cognitive decline increased preferences for deprescribing for geriatricians (OR 1.17, 95% CI 1.03-1.33) and carers (OR 1.27, 95% CI 1.09-1.48). Avoiding falls increased preferences for deprescribing for clinicians (geriatricians (OR 1.20, 95% CI 1.11-1.29); non-geriatricians (OR 1.16, 95% CI 1.07-1.25)). Other attributes did not significantly influence respondent preferences.

CONCLUSIONS

Antihypertensive deprescribing preferences differ amongst people with dementia, carers and clinicians. The study emphasises the importance of shared decision-making within the deprescribing process.

Do we agree or disagree? A systematic review of the application of preference-based instruments in self and proxy reporting of quality of life in older people

PURPOSE

Quality of life is an important person-centred outcome in health and aged care settings. Due to an increasing prevalence of cognitive decline and dementia in ageing populations, a proportion of older people receiving health and aged care services may not be able to reliably assess their own quality of life, highlighting the need for proxy assessment. This systematic review sought to investigate the level of agreement between self and proxy-report of older people's quality of life using established preference-based instruments of quality of life suitable for economic evaluation.

METHODS

A systematic review was conducted following PRISMA guidelines. Eight databases were searched: Web of Science, Scopus, Medline, Econlit, PsychINFO, CINAHL, Ageline and Cochrane Library. Information was extracted on the instruments, population samples (including any cognitive thresholds applied), mean scores, type of proxy, and measures of inter-rater agreement.

RESULTS

A total of 50 studies using eight different preference-based quality of life instruments were identified. Most studies were cross-sectional (72%) with a wide variety of cognitive assessments and thresholds applied to define older participants with cognitive impairment. The most common proxies were family members, mostly spouses. The level of agreement between self and proxy-report was generally poor - irrespective of the instrument applied or type of proxy - with proxy-report generally indicating lower levels of quality of life than self-report. There was some evidence of stronger agreement on more observable quality of life domains e.g., physical health and mobility, relative to less observable domains e.g. emotional well-being. Few studies tracked self and/or proxy-report of quality of life longitudinally.

CONCLUSIONS

More research is needed to develop evidence to inform guidance on self-report versus proxy-report of quality of life for older people receiving health and aged care services. Until then, the collection of both self and proxy reports as complementary measures is indicated.

Developing the Breast Utility Instrument to Measure Health-Related Quality-of-Life Preferences in Patients with Breast Cancer: Selecting the Item for Each Dimension

Introduction. Generic preference-based instruments inadequately measure breast cancer (BrC) health-related quality-of-life preferences given advances in therapy. Our overall purpose is to develop the Breast Utility Instrument (BUI), a BrC-specific preference-based instrument. This study describes the selection of the BUI items. Methods. A total of 408 patients from diverse BrC health states completed the EORTC QLQ-C30 and BR45 (breast module). For each of 10 dimensions previously assessed with confirmatory factor analysis, we evaluated data fit to the Rasch model based on global model and item fit, including threshold ordering, item residuals, infit and outfit, differential item functioning (age), and unidimensionality. Misfitting items were removed iteratively, and the model fit was reassessed. From items fitting the Rasch model, we selected 1 item per dimension based on high patient- and clinician-rated item importance, breadth of item thresholds, and clinical relevance. Results. Global model fit was good in 7 and borderline in 3 dimensions. Separation index was acceptable in 4 dimensions. Item selection criteria were maximized for the following items: 1) physical functioning (trouble taking a long walk), 2) emotional functioning (worry), 3) social functioning (interfering with social activities), 4) pain (having pain), 5) fatigue (tired), 6) body image (dissatisfied with your body), 7) systemic therapy side effects (hair loss), 8) sexual functioning (interest in sex), 9) breast symptoms (oversensitive breast), and 10) endocrine therapy symptoms (problems with your joints). Conclusions. We propose 10 items for the BUI. Our next steps include assessing the measurement properties prior to eliciting preference weights of the BUI.

Highlights

A previous confirmatory factor analysis established 10 dimensions of the European Organisation for Research and Treatment of Cancer (EORTC) core quality of life questionnaire (QLQ-C30) and its breast module (BR45). In this study, we selected 1 item per dimension based on fit to the Rasch model, patient- and clinician-rated item importance, breadth of item thresholds, and clinical relevance. These items form the core of the future Breast Utility Instrument (BUI). The future BUI will be a novel breast cancer–specific preference-based instrument that potentially will better reflect women’s preferences in clinical decision making and cost utility analyses.

Building clinically relevant outcomes across the Alzheimer's disease spectrum

Demonstrating that treatments are clinically meaningful across the Alzheimer's disease (AD) continuum is critical for meeting our goals of accelerating a cure by 2025. While this topic has been a focus of several Alzheimer's Association Research Roundtable (AARR) meetings, there remains no consensus as to what constitutes a "clinically meaningful outcome" in the eyes of patients, clinicians, care partners, policymakers, payers, and regulatory bodies. Furthermore, the field has not come to agreement as to what constitutes a clinically meaningful treatment effect at each stage of disease severity. The AARR meeting on November 19-20, 2019, reviewed current approaches to defining clinical meaningfulness from various perspectives including those of patients and care partners, clinicians, regulators, health economists, and public policymakers. Participants discussed approaches that may confer clinical relevance at each stage of the disease continuum and fostered discussion about what should guide us in the future.

Some gain for a small investment: An economic evaluation of an exercise program for people living in residential aged care

OBJECTIVE

To evaluate the cost-effectiveness of a 12-week Exercise Physiology (EP) program for people living in a residential aged care facility.

METHODS

A within-study pre- and postintervention design to calculate incremental cost-effectiveness ratios per quality-adjusted life years gained. A health service provider perspective was used.

RESULTS

Fifty-nine participants enrolled in a 12-week program. The program cost was A$514.30 per resident. At a willingness-to-pay threshold of A$64 000, the likelihood of being cost-effective of the program is approximately 60%, due to a small increase in participants' quality of life, as reported by care staff. The model showed great variance, depending on who rated the participants' quality of life outcomes.

CONCLUSION

It is uncertain that a 12-week EP program is cost-effective based on the evidence of the current trial. However, it appears that a low-cost program can produce small improvements for residents in care facilities.

Valuing the AD-5D Dementia Utility Instrument: An Estimation of a General Population Tariff

OBJECTIVE

This paper reports on the valuation of quality-of-life states in the Alzheimer's Disease Five Dimensions (AD-5D) instrument in a representative sample of the general population in Australia using the discrete-choice experiment with duration (DCE_TTO) elicitation technique.

METHOD

A DCE with 200 choice sets of two quality-of-life (QoL) state-duration combinations blocked into 20 survey versions, with ten choice sets in each version, was designed and administered online to a sample representative of the Australian population. Two additional choice sets comprising internal consistency and dominance checks were included in each survey version. A range of model specifications investigating preferences with respect to duration and interactions between AD-5D dimension levels were estimated. Utility weights were developed, with estimated coefficients transformed to the 0 (being dead) to 1 (full health) scale, suitable for the calculation of quality-adjusted life-year (QALY) weights for use in economic evaluation.

RESULTS

In total, 1999 respondents completed the choice experiment. Overall, respondents were slightly better educated and had higher annual incomes than the Australian general population. The estimation results from different specifications and models were broadly consistent with the monotonic nature of the AD-5D: utility increased with increased life expectancy and decreased as the severity level for each dimension worsened. A utility value set was generated for the calculation of utilities for all QoL states defined by the AD-5D descriptive system.

CONCLUSION

The DCE-based utility value set is now available to use to generate QALYs for the economic evaluation of treatments and interventions targeting people with dementia and/or their family caregivers.

A qualitative exploration of the content and face validity of preference-based measures within the context of dementia

BACKGROUND

Assessing the cost-effectiveness of interventions for people with dementia, based on cost per quality-adjusted life years (QALYs) gained, requires that the measures used to derive QALYs are preference-based whilst also being valid, feasible to use, comprehensible and acceptable for people with dementia. The aim of this study was to assess the content and face validity of six preference-based measures (PBMs) within the context of dementia.

METHODS

Qualitative focus groups and interviews were conducted with community-dwelling individuals with mild dementia and carers of people with dementia. After exploring participants' understanding of 'quality of life' (QoL), six PBMs were assessed for content and face validity: two measures assessing health-related QoL (EQ-5D-5L and AQoL-8D); two covering broader aspects of capability wellbeing and social care-related QoL (ICECAP-O and ASCOT); and two dementia-specific QoL measures (DEMQOL-U and AD-5D). A random mix of one health-related QoL measure, one wellbeing measure, and one dementia-specific measure was explored in each session. All sessions were audiotaped and transcribed verbatim. Data were analysed thematically.

RESULTS

Nine individuals with mild dementia and 17 carers of people with dementia participated across 4 focus groups and 10 interviews. Participants perceived 9 broad QoL domains as relevant to them: Activity, Autonomy, Cognition, Communication, Coping, Emotions, End-of-Life, Physical Functioning, and Relationships. These domains had limited overlap with the content of the six PBMs. Assessment of face validity was summarized into eight themes: (1) ambiguous questions, (2) double -barrelled questions, (3) difficult/abstract questions, (4) judgemental/confronting questions, (5) lack of relevance and comprehensiveness, (6) response options, (7) layout/format and (8) proxy-response. There was no clear preference for one of the six measures explored; participants identified advantages and disadvantages across all measures. Although particularly designed for individuals with dementia, dementia-specific QoL measures were not always favoured over non-specific measures.

CONCLUSION

Given the shortcomings of PBMs identified in this study, further empirical comparative analyses are necessary to guide the selection of PBMs for future dementia research.

Acceptability and Validity of the EQ-5D in Patients Living With Dementia

OBJECTIVES

To assess the acceptability and validity of the 3 levels of the EQ-5D (EQ-5D-3L) compared with the Quality of Life in Alzheimer's Diseases (QoL-AD) in patients living with dementia.

METHODS

The analysis was based on 560 dyads of persons with dementia and their caregivers of the multicenter observational study of dementia care networks in Germany (DemNet-D). Health-related quality of life was assessed by face-to-face interviews using the EQ-5D-3L (self-rating) and the QoL-AD (self- and proxy-rating). The number of missing values, the score ranges (observed vs possible range) and the floor and ceiling effects were used to assess the acceptability. We used one-way analyses of variance and multivariate linear regression models to evaluate the discriminative ability. The convergent validity was assessed using Spearman's correlation coefficient (r_s) and multivariate regression models.

RESULTS

The EQ-5D index had a higher response rate (89% vs 84%) and a comparable floor (>1%) but a higher ceiling effect (18% vs >1%) compared with the QoL-AD. Both measures can significantly differentiate between different stages of general health, instrumental activities of daily living, and depression. The EQ-5D index and the visual analog scale self-rating scores strongly correlated with the QoL-AD self-rating (r_s = 0.644 and 0.553, respectively) but not with the proxy-rating score (r_s = 0.314 and r_s = 0.170, respectively), which was confirmed by multivariate regression analyses.

CONCLUSION

The results satisfy acceptability, discriminative ability, and convergent validity for moderately cognitively and functionally impaired patients living with dementia. The EQ-5D-3L performed comparably with the QoL-AD, and could, therefore, be used in economic evaluations in dementia. The differences between self- and proxy-ratings should be evaluated and considered in the interpretation of health-related quality of life scores.

How do people with dementia and family carers value dementia-specific quality of life states? An explorative "Think Aloud" study

OBJECTIVE

To investigate the decision-making processes applied by people with dementia and family carers participating in using health economic approaches to value dementia-specific quality of life states.

METHODS

People with dementia (n = 13) and family carers (n = 14) participated in valuing quality of life states using two health economic approaches: Discrete Choice Experiment (DCE) and Best Worst Scaling (BWS). Participants were encouraged to explain their reasoning using a "Think Aloud" approach.

RESULTS

People with dementia and family carers adopted a range of decision-making strategies including "anchoring" the presented states against current quality of life, or simplifying the decision-making by focusing on the sub-set of attributes deemed most important. Overall, there was strong evidence of task engagement for BWS and DCE.

CONCLUSIONS

Health economic valuation approaches can be successfully applied with people with dementia and family carers. These data can inform the assessment of benefits from their perspectives for incorporation within economic evaluation.

How Should We Capture Health State Utility in Dementia? Comparisons of DEMQOL-Proxy-U and of Self- and Proxy-Completed EQ-5D-5L

BACKGROUND

Dementia-specific and proxy-completed preference-based measures have been proposed for use in intervention studies involving people living in residential care, in instances where generic, self-reported preference-based measures have been deemed inappropriate.

OBJECTIVE

This study was conducted to investigate the construct validity, criterion validity, and responsiveness of DEMQOL-Proxy-U and of self- and proxy-completed EQ-5D-5L.

METHODS

The analysis used a 3-wave, individual-level data set of 1004 people living with dementia in residential care that included self-completed EQ-5D-5L and formal-carer and informal-carer proxy-completed EQ-5D-5L and DEMQOL-Proxy-U utility values, in addition to other nonutility cognitive measures (Functional Assessment Staging [FAST], Clinical Dementia Rating [CDR], Cohen-Mansfield Agitation Inventory [CMAI]) and health-related quality of life (HRQOL) measures (nursing home version of the Quality of Life with Alzheimer's disease scale [QOL-AD-NH], Quality of Life in Late-Stage Dementia [QUALID] scale). Construct validity, criterion validity, and responsiveness were assessed using correlation, Bland-Altman plots, and panel data regression models.

RESULTS

Self-completed EQ-5D-5L failed to reflect clinically important differences and changes in FAST, CDR, and CMAI but did capture the resident's own view of HRQOL (QOL-AD-NH). As dementia severity increased, collection of EQ-5D-5L-proxy and DEMQOL-Proxy-U data was more feasible than collection of self-completed EQ-5D-5L. These formal-carer and informal-carer proxy measures also better reflected changes in FAST, CDR, and CMAI but did not capture the resident's own view of HRQOL (QOL-AD-NH), despite adequately capturing the proxy's own view of the resident's HRQOL (QUALID). This indicates discrepancies between a proxy's view and resident's view of the impact that tangible declines in health, cognition, or functional abilities have on HRQOL. The EQ-5D-5L-proxy and DEMQOL-Proxy-U were generally poor substitutes. Regardless of which proxy completed it, the EQ-5D-5L-proxy was typically more responsive than the DEMQOL-Proxy-U to changes in CDR, FAST, and CMAI, indicating that use of the DEMQOL-Proxy-U is not always justified.

CONCLUSION

Disparities in the measurement properties of different utility measures mean that choices about how to measure utility in trials could affect economic evaluation outcomes and hence how resources are allocated for dementia care.

Confirmatory analysis of a health state classification system for people living with dementia: a qualitative approach

Objectives

This paper aims to confirm the content validity of the domains identified during the development of the Alzheimer’s disease – five dimensions (AD-5D) algorithm for the quality of life – Alzheimer’s disease (QOL-AD) and to identify the rationale for stated quality of life preferences.

Methods

Focus groups were conducted to elicit the priorities for quality of life in dementia from three perspectives: the person with dementia; family caregivers; and the community. Participants were recruited through industry research partners (long-term care providers) based on knowledge of their experience with dementia. Three focus groups were conducted – one each in Brisbane, Sydney and Adelaide, Australia – between November 2016 and February 2017. Each focus group included participants providing a different perspective on dementia – people with dementia ( n = 3), caregivers ( n = 9) and general community members or relatives of residents of a long-term care facility ( n = 10), although some groups contained one participant with a different perspective. The focus groups were used to validate the AD-5D domains and examine quality of life preferences across the three perspectives. Thematic analysis was used to identify the priorities underlying preference selection.

Results

All activities affecting the quality of life for people with dementia could be mapped to one of the five AD-5D domains: memory, mood, physical health, living situation and ability to do things for fun. The domains considered most important for quality of life differed between people with dementia, their caregivers and members of the community, with memory the least important domain for all three groups. The rationale for priorities also varied between groups.

Conclusions

This study confirmed the content validity of the selection of the AD-5D domains and identified multiple differences in the reasons behind stated priorities for quality of life for people with dementia, their caregivers and community members.

Health-related quality of life and related factors among a sample of older people with cognitive impairment

AIM

This study aimed to identify factors affecting health-related quality of life (HRQoL) of older adults with cognitive impairment and to describe the association of these factors with different components of HRQoL.

DESIGN

A cross-sectional, descriptive research design was used.

METHODS

Data were collected from 247 individuals aged 60 years and older from a Swedish longitudinal cohort study. The Short-Form Health Survey-12 (SF-12) and EuroQol (EQ-5D) were used to assess HRQoL. The data were analysed using descriptive and comparative statistics.

RESULTS

The present study identified several factors that influenced HRQoL of older adults with cognitive impairment. The results of a multiple logistic regression analysis revealed that the following factors were associated with physical and mental HRQoL: dependency in activities of daily living (ADL), receiving informal care and feelings of loneliness and pain.

Lack of cross-cultural validity of the Endometriosis Health Profile-30

Introduction:

The Endometriosis Health Profile-30 is a disease-specific patient-reported outcome measure of health-related quality of life. Cross-cultural validation of the Endometriosis Health Profile-30 has been performed for several translated versions. The aim of this study was to evaluate the measurement properties of a Norwegian version Endometriosis Health Profile-30.

Methods:

This study was designed as a cross-sectional anonymous postal questionnaire study. A total of 157 women with endometriosis were included during a period from 2012 to 2013. Women aged 18–45 years were recruited from the Norwegian Endometriosis Association. Principal components analysis with varimax rotation was used to assess construct validity. Short Form-36 was used to determine convergent validity. Cronbach’s alpha was used to measure internal consistency. Intraclass correlation coefficients and paired t-tests were used to evaluate test–retest reliability. Floor and ceiling effects were estimated.

Results:

Factor analysis resulted in a three and five-factor model for the core and modular questionnaire, respectively. Factor analysis could not support construct validity of the scales self-image and treatment. The Norwegian version Endometriosis Health Profile-30 demonstrated acceptable internal consistency and test–retest reliability, except for the scale relationship with children. Floor effects were observed for the scales self-image (20.1%), work life (33.9%), relationship with children (34.2%), and medical profession (20.5%).

Conclusion:

The construct self-image does not seem to be measured appropriately by the Norwegian version Endometriosis Health Profile-30, suggesting a lack of cross-cultural validity of the Endometriosis Health Profile-30. With multinational studies increasing, adequate translation, cross-cultural adaptation, and cross-cultural validation of instruments are essential to ensure equivalence in languages and cultures other than the original.

Economics of dementia: A review of methods

Given the expected increase in the number of people with dementia in the coming years, it is anticipated that the resources necessary to support those with dementia will significantly increase. There will therefore likely be increased emphasis on how best to use limited resources across a number of domains including prevention, diagnosis, treatment and supporting informal caregivers. There has been increasing use of economic methods in dementia in the past number of years, in particular, cost-of-illness analysis and economic evaluation. This paper reviews the aforementioned methods and identities a number of methodological issues that require development. Addressing these methodological issues will enhance the quality of economic analysis in dementia and provide some useful insights about the best use of limited resources for dementia.