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

A Potential Role for the Ketogenic Diet in Alzheimer's Disease Treatment: Exploring Pre-Clinical and Clinical Evidence

Given the remarkable progress in global health and overall quality of life, the significant rise in life expectancy has become intertwined with the surging occurrence of neurodegenerative disorders (NDs). This emerging trend is poised to pose a substantial challenge to the fields of medicine and public health in the years ahead. In this context, Alzheimer's disease (AD) is regarded as an ND that causes recent memory loss, motor impairment and cognitive deficits. AD is the most common cause of dementia in the elderly and its development is linked to multifactorial interactions between the environment, genetics, aging and lifestyle. The pathological hallmarks in AD are the accumulation of β-amyloid peptide (Aβ), the hyperphosphorylation of tau protein, neurotoxic events and impaired glucose metabolism. Due to pharmacological limitations and in view of the prevailing glycemic hypometabolism, the ketogenic diet (KD) emerges as a promising non-pharmacological possibility for managing AD, an approach that has already demonstrated efficacy in addressing other disorders, notably epilepsy. The KD consists of a food regimen in which carbohydrate intake is discouraged at the expense of increased lipid consumption, inducing metabolic ketosis whereby the main source of energy becomes ketone bodies instead of glucose. Thus, under these dietary conditions, neuronal death via lack of energy would be decreased, inasmuch as the metabolism of lipids is not impaired in AD. In this way, the clinical picture of patients with AD would potentially improve via the slowing down of symptoms and delaying of the progression of the disease. Hence, this review aims to explore the rationale behind utilizing the KD in AD treatment while emphasizing the metabolic interplay between the KD and the improvement of AD indicators, drawing insights from both preclinical and clinical investigations. Via a comprehensive examination of the studies detailed in this review, it is evident that the KD emerges as a promising alternative for managing AD. Moreover, its efficacy is notably enhanced when dietary composition is modified, thereby opening up innovative avenues for decreasing the progression of AD.

Health-related quality of life in subjective cognitive decline and mild cognitive impairment: a longitudinal cohort analysis

BACKGROUND

Health-related quality of life (HR-QoL) is an important outcome for patients and crucial for demonstrating the value of new treatments. Health utility estimates in subjective cognitive decline (SCD) and mild cognitive impairment (MCI) are limited, especially in biomarker-confirmed populations. Besides, little is known about the longitudinal HR-QoL trajectory. This study aims to provide health utility estimates for SCD and MCI and investigate the QoL trajectory along the disease continuum.

METHODS

Longitudinal data from 919 SCD and 1336 MCI patients from the MEMENTO cohort were included. SCD was defined as clinical dementia rating (CDR) = 0, and MCI as CDR = 0.5. HR-QoL was measured using the EQ-5D-3L patient-reported instrument. Linear mixed-effect models (LMM) were used to assess the longitudinal change in HR-QoL and identify predictors of these changes.

RESULTS

Baseline health utilities were 0.84 ± 0.16 and 0.81 ± 0.18, and visual analogue scale (VAS) were 75.8 ± 14.82 and 70.26 ± 15.77 in SCD and MCI. In amyloid-confirmed cases, health utilities were 0.85 ± 0.14 and 0.86 ± 0.12 in amyloid-negative and amyloid-positive SCD, and 0.83 ± 0.17 and 0.84 ± 0.16 in amyloid-negative and amyloid-positive MCI. LMM revealed an annual decline in health utility of - 0.015 (SE = 0.006) and - 0.09 (SE = 0.04) in moderate and severe dementia (P < 0.05). There was a negative association between clinical stage and VAS where individuals with MCI, mild, moderate, and severe dementia were on average 1.695 (SE = 0.274), 4.401 (SE = 0.676), 4.999 (SE = 0.8), and 15.386 (SE = 3.142) VAS points lower than individuals with SCD (P < 0.001). Older age, female sex, higher body mass index, diabetes, cardiovascular history, depression, and functional impairment were associated with poor HR-QoL. Amyloid positivity was associated with an annual decline of - 0.011 (SE = 0.004, P < 0.05) health utility over time.

CONCLUSIONS

Health utility estimates from this study can be used in economic evaluations of interventions targeting SCD and MCI. Health utility declines over time in moderate and severe dementia, and VAS declines with advancing clinical stages. Amyloid-positive patients show a faster decline in health utility indicating the importance of considering biomarker status in HR-QoL assessments. Future research is needed to confirm the longitudinal relationship between amyloid status and HR-QoL and to examine the level at which depression and IADL contribute to HR-QoL decline in AD.

Convergent validity of EQ-5D with core outcomes in dementia: a systematic review

Objectives

To explore through a systematic review, the convergent validity of EQ-5D (EQ-5D-3L and EQ-5D-5L (total score and dimensions)) with core outcomes in dementia and investigate how this may be impacted by rater-type; with the aim of informing researchers when choosing measures to use in dementia trials.

Methods

To identify articles relevant to the convergent validity of EQ-5D with core dementia outcomes, three databases were electronically searched to September 2022. Studies were considered eligible for inclusion within the review if they included individual level data from people with dementia of any type, collected self and/or proxy reported EQ-5D and collected at least one core dementia outcome measure. Relevant data such as study sample size, stage of dementia and administration of EQ-5D was extracted, and a narrative synthesis was adopted.

Results

The search strategy retrieved 271 unique records, of which 30 met the inclusion criteria for the review. Twelve different core outcome measures were used to capture dementia outcomes: cognition, function, and behaviour/mood across the studies. Most studies used EQ-5D-3L (n = 27). Evidence related to the relationship between EQ-5D and measures of function and behaviour/mood was the most robust, with unanimous directions of associations, and more statistically significant findings. EQ-5D dimensions exhibited associations with corresponding clinical outcomes, whereby relationships were stronger with proxy-EQ-5D (than self-report).

Conclusion

Measuring health-rated quality of life in dementia populations is a complex issue, particularly when considering balancing the challenges associated with both self and proxy report. Published evidence indicates that EQ-5D shows evidence of convergent validity with the key dementia outcomes, therefore capturing these relevant dementia outcomes. The degree of associations with clinical measures was stronger when considering proxy-reported EQ-5D and differed by EQ-5D dimension type. This review has revealed that, despite the limited targeted psychometric evidence pool and reliance on clinical and observational studies, EQ-5D exhibits convergent validity with other dementia outcome measures.

Assessing the psychometric performance of EQ-5D-5L in dementia: a systematic review

BACKGROUND

EQ-5D is widely used for valuing changes in quality of life for economic evaluation of interventions for people with dementia. There are concerns about EQ-5D-3L in terms of content validity, poor inter-rater agreement and reliability in the presence of cognitive impairment, but there is also evidence to support its use with this population. An evidence gap remains regarding the psychometric properties of EQ-5D-5L.

OBJECTIVES

To report psychometric evidence around EQ-5D-5L in people with dementia.

METHODS

A systematic review identified primary studies reporting psychometric properties of EQ-5D-5L in people with dementia. Searches were completed up to November 2020. Study selection, data extraction and quality assessment were undertaken independently by at least 2 researchers.

RESULTS

Evidence was extracted from 20 articles from 14 unique studies covering a range of dementia severity. Evidence of known group validity from 5 of 7 studies indicated that EQ-5D-5L distinguishes severity of disease measured by cognitive impairment, depression, level of dependence and pain. Convergent validity (9 studies) showed statistically significant correlations of weak and moderate strengths, between EQ-5D-5L scores and scores on other key measures. Statistically significant change was observed in only one of 6 papers that allowed this property to be examined. All seven studies showed a lack of inter-rater reliability between self and proxy reports with the former reporting higher EQ-5D-5L scores than those provided by proxies. Five of ten studies found EQ-5D-5L to be acceptable, assessed by whether the measure could be completed by the PwD and/or by the amount of missing data. As dementia severity increased, the feasibility of self-completing EQ-5D-5L decreased. Three papers reported on ceiling effects, two found some evidence in support of ceiling effects, and one did not.

CONCLUSIONS

EQ-5D-5L seems to capture the health of people with dementia on the basis of known-group validity and convergent validity, but evidence is inconclusive regarding the responsiveness of EQ-5D-5L. As disease progresses, the ability to self-complete EQ-5D-5L is diminished.

Estimation of Utility Values for Computing Quality-adjusted Life Years Associated With Homelessness

BACKGROUND

There is a lack of data-driven evidence about the burden of homelessness, and lack of a holistic measure of effectiveness for evaluating interventions targeting homelessness. Quality-adjusted life years (QALYs) can help holistically capture the burden of homelessness, and facilitate the valuation and comparison of interventions designed to address homelessness.

OBJECTIVE

This study estimated utility values required to compute the QALYs associated with homelessness, and also examined individual-level characteristics that affect these values.

RESEARCH DESIGN

The study is cross-sectional and derived from a large national survey conducted during the coronavirus disease 2019 pandemic.

SUBJECTS

A sample of 6607 middle- and low-income adults in the United States.

MEASURES

A self-completion standard gamble survey was used to estimate utility values associated with homelessness. Linear regression was used to analyze the association between individual-level characteristics and these utility values.

RESULTS

The study estimated the average utility value associated with homelessness as 43.4% among the study participants. This implies that 1 year of life as a homeless individual is perceived to be equivalent to less than half a year of life as a stably housed individual in good health. The study also found that individuals who have experienced homelessness and financial distress value life as a homeless person considerably less than those who have not had these experiences.

CONCLUSIONS

The method developed in this study can be used to estimate QALYs in studies evaluating homelessness interventions, thereby establishing the societal value of these interventions and informing policy and budgetary decision-making. Future studies estimating the utility values associated with homelessness in the general population, as well as specific homeless groups, are required to provide more generalizable evidence.

Health utility in preclinical and prodromal Alzheimer's disease for establishing the value of new disease-modifying treatments-EQ-5D data from the Swedish BioFINDER study

Quality of life and health utility are important outcomes for patients with Alzheimer's disease (AD) and central for demonstrating the value of new treatments. Estimates in biomarker-confirmed AD populations are missing, potentially delaying payer approval of treatment. We examined whether health utility, assessed with the EuroQoL-5 3-level version (EQ-5D-3L), differed between individuals with a positive or negative amyloid beta (Aβ) biomarker in patients with mild cognitive impairment (MCI) and cognitively unimpaired (CU) participants from the Swedish BioFINDER study (n = 578). Participants with prodromal AD (Aβ-positive MCI) reported better health utility (n = 79, mean = 0.81, 95% confidence interval [CI] 0.77-0.85) than Aβ-negative MCI (mean = 0.71, 95% CI 0.64-0.78), but worse than controls (Aβ-negative CU, mean = 0.87, 95% CI 0.86-0.89). Health utility in preclinical AD (Aβ-positive CU; mean = 0.86, 95% CI 0.83-0.89) was similar to controls. This relatively good health utility in prodromal AD suggests a larger value of delaying progression to dementia than previously anticipated and a great value of delaying clinical progression in preclinical AD.

Obtaining EQ-5D-5L utilities from the disease specific quality of life Alzheimer's disease scale: development and results from a mapping study

PURPOSE

The Quality of Life Alzheimer's Disease Scale (QoL-AD) is commonly used to assess disease specific health-related quality of life (HRQoL) as rated by patients and their carers. For cost-effectiveness analyses, utilities based on the EQ-5D are often required. We report a new mapping algorithm to obtain EQ-5D indices when only QoL-AD data are available.

METHODS

Different statistical models to estimate utility directly, or responses to individual EQ-5D questions (response mapping) from QoL-AD, were trialled for patient-rated and proxy-rated questionnaires. Model performance was assessed by root mean square error and mean absolute error.

RESULTS

The response model using multinomial regression including age and sex, performed best in both the estimation dataset and an independent dataset.

CONCLUSIONS

The recommended mapping algorithm allows researchers for the first time to estimate EQ-5D values from QoL-AD data, enabling cost-utility analyses using datasets where the QoL-AD but no utility measures were collected.

Health-related quality of life in people with predementia Alzheimer's disease, mild cognitive impairment or dementia measured with preference-based instruments: a systematic literature review

BACKGROUND

Obtaining reliable estimates of the health-related quality of life (HR-QoL) of people with predementia Alzheimer's disease [AD] (preclinical or prodromal AD), mild cognitive impairment (MCI) and dementia is essential for economic evaluations of related health interventions.

AIMS

To provide an overview of which quality of life instruments are being used to assess HR-QoL in people with predementia AD, MCI or dementia; and, to summarise their reported HR-QoL levels at each stage of the disease and by type of respondent.

METHODS

We systematically searched for and reviewed eligible studies published between January 1990 and the end of April 2017 which reported HR-QoL for people with predementia AD, MCI or dementia. We only included instruments which are preference-based, allowing index scores/utility values to be attached to each health state they describe based on preferences obtained from population surveys. Summary results were presented by respondent type (self or proxy), type of instrument, geographical location and, where possible, stage of disease. Health state utility values derived using the EuroQoL 5-Dimensions (EQ-5D) were meta-analysed by pooling reported results across all studies by disease severity (MCI, mild, mild to moderate, moderate, severe dementia, not specified) and by respondent (person with dementia, carer, general public, not specified), using a fixed-effects approach.

RESULTS

We identified 61 studies which reported HR-QoL for people with MCI or dementia using preference-based instruments, of which 48 used the EQ-5D. Thirty-six studies reported HR-QoL for mild and/or moderate disease severities, and 12 studies reported utility values for MCI. We found systematic differences between self-rated and proxy-rated HR-QoL, with proxy-rated utility valued being significantly lower in more severe disease states.

CONCLUSIONS

A substantial literature now exists quantifying the impact of dementia on HR-QoL using preference-based measures, giving researchers and modellers a firmer basis on which to select appropriate utility values when estimating the effectiveness and cost-effectiveness of interventions in this area. Further research is required on HR-QoL of people with preclinical and prodromal AD and MCI, possible differences by type of dementia, the effects of comorbidities, study setting and the informal caregiver's own HR-QoL, including any effect of that on their proxy-ratings.

Tip of the Iceberg: Assessing the Global Socioeconomic Costs of Alzheimer's Disease and Related Dementias and Strategic Implications for Stakeholders

While it is generally understood that Alzheimer’s disease (AD) and related dementias (ADRD) is one of the costliest diseases to society, there is widespread concern that researchers and policymakers are not comprehensively capturing and describing the full scope and magnitude of the socioeconomic burden of ADRD. This review aimed to 1) catalogue the different types of AD-related socioeconomic costs described in the literature; 2) assess the challenges and gaps of existing approaches to measuring these costs; and 3) analyze and discuss the implications for stakeholders including policymakers, healthcare systems, associations, advocacy groups, clinicians, and researchers looking to improve the ability to generate reliable data that can guide evidence-based decision making. A centrally emergent theme from this review is that it is challenging to gauge the true value of policies, programs, or interventions in the ADRD arena given the long-term, progressive nature of the disease, its insidious socioeconomic impact beyond the patient and the formal healthcare system, and the complexities and current deficiencies (in measures and real-world data) in accurately calculating the full costs to society. There is therefore an urgent need for all stakeholders to establish a common understanding of the challenges in evaluating the full cost of ADRD and define approaches that allow us to measure these costs more accurately, with a view to prioritizing evidence-based solutions to mitigate this looming public health crisis.

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.

Factors associated with long-term impact on informal caregivers during Alzheimer's disease dementia progression: 36-month results from GERAS

OBJECTIVE

To identify, in caregivers of patients with Alzheimer's disease (AD) dementia, factors associated with subjective (personal, physical, emotional, and social) and objective (informal caregiver time and costs) caregiver burden.

DESIGN

Prospective longitudinal European observational study: post-hoc analysis.

SETTING

Clinic.

PARTICIPANTS

Community-dwelling patients in France and Germany aged ≥ 55 years (n = 969) with probable AD and their informal caregivers.

MEASUREMENTS

Mini-Mental State Examination (MMSE), Alzheimer's Disease Cooperative Study-Activities of Daily Living (ADCS-ADL), 12-item Neuropsychiatric Inventory (NPI-12), Zarit Burden Interview (ZBI), informal caregiver basic and instrumental ADL hours (Resource Utilization in Dementia instrument), and informal caregiver costs. Mixed-effect models of repeated measures (MMRM) were run, including baseline and time-dependent covariates (change from baseline [CFB] to 18 months in MMSE, ADCS-ADL, and NPI-12 scores) associated with CFB in ZBI score/informal caregiver time over 36 months (analyzed using linear regression models) and informal caregiver costs over 36 months (analyzed using generalized linear models).

RESULTS

Greater decline in patient function (ADCS-ADL) over 18 months was associated with increased subjective caregiver burden (ZBI), hours, and costs over 36 months. Increased behavioral problems (NPI-12) over 18 months also negatively impacted ZBI. Cognitive decline (MMSE) over 18 months did not affect change in caregiver burden.

CONCLUSIONS

Long-term informal caregiver burden was driven by worsening functional abilities and behavioral symptoms but not cognitive decline, over 18 months in community-dwelling patients with AD dementia. Identifying the drivers of caregiver burden could highlight areas in which interventions may benefit both caregivers and patients.

A Review of the Development and Application of Generic Preference-Based Instruments with the Older Population

Older people (aged 65 years and over) are the fastest growing age cohort in the majority of developed countries, and the proportion of individuals defined as the oldest old (aged 80 years and over) living with physical frailty and cognitive impairment is rising. These population changes put increasing pressure on health and aged care services, thus it is important to assess the cost effectiveness of interventions targeted for older people across health and aged care sectors to identify interventions with the strongest capacity to enhance older peoples' quality of life and provide value for money. Cost-utility analysis (CUA) is a form of economic evaluation that typically uses preference-based instruments to measure and value health-related quality of life for the calculation of quality-adjusted life-years (QALYS) to enable comparisons of the cost effectiveness of different interventions. A variety of generic preference-based instruments have been used to measure older people's quality of life, including the Adult Social Care Outcomes Toolkit (ASCOT); Health Utility Index Mark 2 (HUI2); Health Utility Index Mark 3 (HUI3); Short-Form-6 Dimensions (SF-6D); Assessment of Quality of Life-6 dimensions (AQoL-6D); Assessment of Quality of Life-8 dimensions (AQoL-8D); Quality of Wellbeing Scale-Self-Administered (QWB-SA); 15 Dimensions (15D); EuroQol-5 dimensions (EQ-5D); and an older person specific preference-based instrument-the Investigating Choice Experiments Capability Measure for older people (ICECAP-O). This article reviews the development and application of these instruments within the older population and discusses the issues surrounding their use with this population. Areas for further research relating to the development and application of generic preference-based instruments with populations of older people are also highlighted.

Should we provide outreach rehabilitation to very old people living in Nursing Care Facilities after a hip fracture? A randomised controlled trial

OBJECTIVE

to determine whether a 4-week postoperative rehabilitation program delivered in Nursing Care Facilities (NCFs) would improve quality of life and mobility compared with receiving usual care.

DESIGN

parallel randomised controlled trial with integrated health economic study.

SETTING

NCFs, in Adelaide South Australia.

SUBJECTS

people aged 70 years and older who were recovering from hip fracture surgery and were walking prior to hip fracture.

MEASUREMENTS

primary outcomes: mobility (Nursing Home Life-Space Diameter (NHLSD)) and quality of life (DEMQOL) at 4 weeks and 12 months.

RESULTS

participants were randomised to treatment (n = 121) or control (n = 119) groups. At 4 weeks, the treatment group had better mobility (NHLSD mean difference -1.9; 95% CI: -3.3, -0.57; P = 0.0055) and were more likely to be alive (log rank test P = 0.048) but there were no differences in quality of life. At 12 months, the treatment group had better quality of life (DEMQOL sum score mean difference = -7.4; 95% CI: -12.5 to -2.3; P = 0.0051), but there were no other differences between treatment and control groups. Quality adjusted life years (QALYs) gained over 12 months were 0.0063 higher per participant (95% CI: -0.0547 to 0.0686). The resulting incremental cost effectiveness ratios (ICERs) were $5,545 Australian dollars per unit increase in the NHLSD (95% CI: $244 to $15,159) and $328,685 per QALY gained (95% CI: $82,654 to $75,007,056).

CONCLUSIONS

the benefits did not persist once the rehabilitation program ended but quality of life at 12 months in survivors was slightly higher. The case for funding outreach home rehabilitation in NCFs is weak from a traditional health economic perspective.

TRIAL REGISTRATION

ACTRN12612000112864 registered on the Australian and New Zealand Clinical Trials Registry. Trial protocol available at https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id = 361980.

Toward a Centralized, Systematic Approach to the Identification, Appraisal, and Use of Health State Utility Values for Reimbursement Decision Making: Introducing the Health Utility Book (HUB)

Cost-utility analysis (CUA) is a widely recommended form of health economic evaluation worldwide. The outcome measure in CUA is quality-adjusted life-years (QALYs), which are calculated using health state utility values (HSUVs) and corresponding life-years. Therefore, HSUVs play a significant role in determining cost-effectiveness. Formal adoption and endorsement of CUAs by reimbursement authorities motivates methodological advancement in HSUV measurement and application. A large body of evidence exploring various methods in measuring HSUVs has accumulated, imposing challenges for investigators in identifying and applying HSUVs to CUAs. First, large variations in HSUVs between studies are often reported, and these may lead to different cost-effectiveness conclusions. Second, issues concerning the quality of studies that generate HSUVs are increasingly highlighted in the literature. This issue is compounded by the limited published guidance and methodological standards for assessing the quality of these studies. Third, reimbursement decision making is a context-specific process. Therefore, while an HSUV study may be of high quality, it is not necessarily appropriate for use in all reimbursement jurisdictions. To address these issues, by promoting a systematic approach to study identification, critical appraisal, and appropriate use, we are developing the Health Utility Book (HUB). The HUB consists of an HSUV registry, a quality assessment tool for health utility studies, and a checklist for interpreting their use in CUAs. We anticipate that the HUB will make a timely and important contribution to the rigorous conduct and proper use of health utility studies for reimbursement decision making. In this way, health care resource allocation informed by HSUVs may reflect the preferences of the public, improve health outcomes of patients, and maintain the efficiency of health care systems.

Use of Checklists in Reviews of Health Economic Evaluations, 2010 to 2018

OBJECTIVE

It is useful for reviewers of economic evaluations to assess quality in a manner that is consistent and comprehensive. Checklists can allow this, but there are concerns about their reliability and how they are used in practice. We aimed to describe how checklists have been used in systematic reviews of health economic evaluations.

METHODS

Meta-review with snowball sampling. We compiled a list of checklists for health economic evaluations and searched for the checklists' use in systematic reviews from January 2010 to February 2018. We extracted data regarding checklists used, stated checklist function, subject area, number of reviewers, and issues expressed about checklists.

RESULTS

We found 346 systematic reviews since 2010 that used checklists to assess economic evaluations. The most common checklist in use was developed in 1996 by Drummond and Jefferson, and the most common stated use of a checklist was quality assessment. Checklists and their use varied within subject areas; 223 reviews had more than one reviewer who used the checklist.

CONCLUSIONS

Use of checklists is inconsistent. Eighteen individual checklists have been used since 2010, many of which have been used in ways different from those originally intended, often without justification. Different systematic reviews in the same subject areas would benefit from using one checklist exclusively, using checklists as intended, and having 2 reviewers complete the checklist. This would increase the likelihood that results are transparent and comparable over time.

Modelling long-term cost-effectiveness of health promotion for community-dwelling older people

The effectiveness of health promotion for community-dwelling older people is well documented; however, there is a general lack of health economic evaluations. The aim of the present study was to evaluate long-term cost-effectiveness over 4 years of two health promoting interventions: senior meetings and a preventive home visit, for community-dwelling older people in relation to no intervention. We applied a Markov model including five states defined in relation to level of dependency of home help and place of residency. The model included transitions between dependency states, scores for quality of life and societal costs for each state, intervention costs and intervention effects for two formats of health promoting interventions. For each intervention and a no-intervention control group, we calculated the accumulated quality-adjusted life years (QALYs) and societal costs over 4 years. Sensitivity analyses included higher intervention costs, lower intervention effects and additional intervention costs and effects related to booster sessions. The results of all analyses indicated that health promotion implemented for community-dwelling older people in the format of senior meetings or a preventive home visit was cost-effective. Both interventions lead to QALY gains and reduce societal costs at any follow-up over 4 years, and thus, resources can be used to implement other interventions. The most important factor for the magnitude of QALY gains and cost savings was the intervention effect. Yearly booster sessions implemented for those persons who maintained their level of functioning extended the intervention effects adding additional QALYs and further reducing societal costs.

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.

A Practical Guide to Conducting a Systematic Review and Meta-analysis of Health State Utility Values

Economic analysts are increasingly likely to rely on systematic reviews and meta-analyses of health state utility values to inform the parameter inputs of decision-analytic modelling-based economic evaluations. Beyond the context of economic evaluation, evidence from systematic reviews and meta-analyses of health state utility values can be used to inform broader health policy decisions. This paper provides practical guidance on how to conduct a systematic review and meta-analysis of health state utility values. The paper outlines a number of stages in conducting a systematic review, including identifying the appropriate evidence, study selection, data extraction and presentation, and quality and relevance assessment. The paper outlines three broad approaches that can be used to synthesise multiple estimates of health utilities for a given health state or condition, namely fixed-effect meta-analysis, random-effects meta-analysis and mixed-effects meta-regression. Each approach is illustrated by a synthesis of utility values for a hypothetical decision problem, and software code is provided. The paper highlights a number of methodological issues pertinent to the conduct of meta-analysis or meta-regression. These include the importance of limiting synthesis to 'comparable' utility estimates, for example those derived using common utility measurement approaches and sources of valuation; the effects of reliance on limited or poorly reported published data from primary utility assessment studies; the use of aggregate outcomes within analyses; approaches to generating measures of uncertainty; handling of median utility values; challenges surrounding the disentanglement of utility estimates collected serially within the context of prospective observational studies or prospective randomised trials; challenges surrounding the disentanglement of intervention effects; and approaches to measuring model validity. Areas of methodological debate and avenues for future research are highlighted.

An empirical comparison of the measurement properties of the EQ-5D-5L, DEMQOL-U and DEMQOL-Proxy-U for older people in residential care

PURPOSE

This study aimed to empirically compare the measurement properties of self-reported and proxy-reported (in cases of severe cognitive impairment) generic (EQ-5D-5L) and condition-specific (DEMQOL-U and DEMQOL-Proxy-U) preference-based HRQoL instruments in residential care, where the population is characterised by older people with high rates of cognitive impairment, dementia and disability.

METHODS

Participants were recruited from seventeen residential care facilities across four Australian states. One hundred and forty-three participants self-completed the EQ-5D-5L and the DEMQOL-U while three hundred and eight-seven proxy completed (due to the presence of severe dementia) the EQ-5D-5L and DEMQOL-Proxy-U. The convergent validity of the outcome measures and known group validity relative to a series of clinical outcome measures were assessed.

RESULTS

Results satisfy convergent validity among the outcome measures. EQ-5D-5L and DEMQOL-U utilities were found to be significantly correlated with each other (p < 0.01) as were EQ-5D-5L and DEMQOL-Proxy-U utilities (p < 0.01). Both self-reported and proxy-reported EQ-5D-5L utilities demonstrated strong known group validity in relation to clinically recognised thresholds of cognition and physical functioning, while in contrast neither DEMQOL-U nor DEMQOL-Proxy-U demonstrated this association.

CONCLUSIONS

The findings suggest that the EQ-5D-5L, DEMQOL-U and DEMQOL-Proxy-U capture distinct aspects of HRQoL for this population. The measurement and valuation of HRQoL form an essential component of economic evaluation in residential care. However, high levels of cognitive impairment may preclude self-completion for a majority. Further research is needed to determine cognition thresholds beyond which an individual is unable to reliably self-report their own health-related quality of life.

Measuring quality of life of people with predementia and dementia and their caregivers: a systematic review protocol

INTRODUCTION

Dementia is the fastest growing major cause of disability globally and may have a profound impact on the health-related quality of life (HRQoL) of both the patient with dementia and those who care for them. This review aims to systematically identify and synthesise the measurements of HRQoL for people with, and their caregivers across the full spectrum of, dementia from its preceding stage of predementia to end of life.

METHODS AND ANALYSIS

A systematic literature review was conducted in Medical Literature Analysis and Retrieval System Online , ExcerptaMedicadataBASE, Cochrane Database of Systematic Reviews , Cochrane Central Register of Controlled Trials, Database of Abstracts of Reviews of Effect, National Health Service Economic Evaluation Database and PsycINFO between January 1990 and the end of April 2017. Two reviewers will independently assess each study for inclusion and disagreements will be resolved by a third reviewer. Data will be extracted using a predefined data extraction form following best practice. Study quality will be assessed with the Effective Public Health Practice Project quality assessment tool. HRQoL measurements will be presented separately for people with dementia and caregivers by instrument used and, when possible, HRQoL will be reported by disease type and stage of the disease. Descriptive statistics of the results will be provided. A narrative synthesis of studies will also be provided discussing differences in HRQoL measurements by instrument used to estimate it, type of dementia and disease severity.

ETHICS AND DISSEMINATION

This systematic literature review is exempt from ethics approval because the work is carried out on published documents. The findings of the review will be disseminated in a related peer-reviewed journal and presented at conferences. They will also contribute to the work developed in the Real World Outcomes across the Alzheimer's disease spectrum for better care: multimodal data access platform (ROADMAP).

TRIAL REGISTRATION NUMBER

CRD42017071416.

A Systematic Review and Meta-analysis of Childhood Health Utilities

BACKGROUND

A common feature of most reviews or catalogues of health utilities has been their focus on adult health states or derivation of values from adult populations. More generally, utility measurement in or on behalf of children has been constrained by several methodological concerns. The objective of this study was to conduct the first comprehensive systematic review and meta-analysis of primary utility data for childhood conditions and descriptors, and to determine the effects of methodological factors on childhood utilities.

METHODS

The review followed PRISMA guidelines. PubMed, Embase, Web of Science, PsycINFO, EconLit, CINAHL and Cochrane Library were searched for primary studies reporting health utilities for childhood conditions or descriptors using direct or indirect valuation methods. The Paediatric Economic Database Evaluation (PEDE) Porject was also searched for cost-utility analyses with primary utility values. Mean or median utilities for each of the main samples were catalogued, and weighted averages of utilities for each health condition were estimated, by valuation method. Mixed-effects meta-regression using hierarchical linear modeling was conducted for the most common valuation methods to estimate the utility decrement for each health condition category relative to general childhood population health, as well as the independent effects of methodological factors.

RESULTS

The literature searches resulted in 272 eligible studies. These yielded 3,414 utilities when all sub-groups were considered, covering all ICD-10 chapters relevant to childhood health, 19 valuation methods, 12 respondent types, 8 modes of administration, and data from 36 countries. A total of 1,191 utility values were obtained when only main study samples were considered, and these were catalogued by health condition or descriptor, and methodological characteristics. 1,073 mean utilities for main samples were used for fixed-effects meta-analysis by health condition and valuation method. Mixed-effects meta-regressions estimated that 53 of 76 ICD-10 delineated health conditions, valued using the HUI3, were associated with statistically significant utility decrements relative to general population health, whereas 38 of 57 valued using a visual analog scale (VAS) were associated with statistically significant VAS decrements. For both methods, parental proxy assessment was associated with overestimation of values, whereas adolescents reported lower values than children under 12 y. VAS responses were more heavily influenced by mode of administration than the HUI3.

CONCLUSION

Utilities and their associated distributions, as well as the independent contributions of methodological factors, revealed by this systematic review and meta-analysis can inform future economic evaluations within the childhood context.

Targeting β-amyloid plaques and oligomers: development of near-IR fluorescence imaging probes

Evidence indicated that shifting treatment to a presymptomatic stage may produce significant benefits to prevent/alleviate the progression of Alzheimer's disease (AD); in particular, early incorporation of noninvasive imaging and biomarker testing will be significantly beneficial for AD drug development. Based on amyloid cascade hypothesis and its revised version, both β-amyloid deposition and soluble oligomeric species could be good diagnostic biomarkers for AD. Near-IR fluorescence (NIRF) imaging, which so far is limited to animal studies, is a promising method for its incomparable advantages such as low cost, high-throughput and easy operation. This review focuses on recent reported NIRF probes that showed excellent binding to plaques and oligomers. We hope that this review will shed light on the future of NIRF probes' discovery.

How useful is the EQ-5D in assessing the impact of caring for people with Alzheimer's disease?

BACKGROUND

The impact on informal caregivers of caring for people with Alzheimer's disease (AD) dementia can be substantial, but it remains unclear which measures(s) best assess such impact. Our objective was to use data from the GERAS study to assess the ability of the EuroQol 5-dimension questionnaire (EQ-5D) to measure the impact on caregivers of caring for people with AD dementia and to examine correlations between EQ-5D and caregiver burden.

METHODS

GERAS was a prospective, non-interventional cohort study in community-dwelling patients with AD dementia and their informal caregivers. The EQ-5D and Zarit Burden Interview (ZBI) were used to measure health-related quality of life and caregiver burden, respectively. Resource-use data collected included caregiver time spent with the patient on activities of daily living (ADL). Spearman correlations were computed between EQ-5D scores, ZBI scores, and time spent on instrumental ADL (T-IADL) at baseline, 18 months, and for 18-month change scores. T-IADL and ZBI change scores were summarized by EQ-5D domain change category (better/stable/worse).

RESULTS

At baseline, 1495 caregivers had mean EQ-5D index scores of 0.86, 0.85, and 0.82, and ZBI total scores of 24.6, 29.4, and 34.1 for patients with mild, moderate, and moderately severe/severe AD dementia, respectively. Change in T-IADL showed a stronger correlation with change in ZBI (0.12; P < 0.001) than with change in EQ-5D index score (0.02; P = 0.546) although both correlations were very weak. Worsening within EQ-5D domains was associated with increases in ZBI scores, although 68%-90% of caregivers remained stable within each EQ-5D domain. There was no clear pattern for change in T-IADL by change in EQ-5D domain.

CONCLUSIONS

EQ-5D may not be the optimum measure of the impact of caring for people with AD dementia due to its focus on physical health. Alternative measures need further investigation.

Cost effectiveness of an intervention focused on reducing bathing disability

The onset of bathing disability among older people is critical for a decline in functioning and has implications for both the individuals’ quality of life and societal costs. The aim of this study was to evaluate long-term cost effectiveness of an intervention targeting bathing disability among older people. For hypothetical cohorts of community-dwelling older people with bathing disability, transitions between states of dependency and death were modelled over 8 years including societal costs. A five-state Markov model based on states of dependency was used to evaluate Quality-adjusted life years (QALYs) and costs from a societal perspective. An intervention group was compared with a no intervention control group. The intervention focused on promoting safe and independent performance of bathing-related tasks. The intervention effect, based on previously published trials, was applied in the model as a 1.4 increased probability of recovery during the first year. Over the full follow-up period, the intervention resulted in QALY gains and reduced societal cost. After 8 years, the intervention resulted in 0.052 QALYs gained and reduced societal costs by €2410 per person. In comparison to the intervention cost, the intervention effect was a more important factor for the magnitude of QALY gains and long-term societal costs. The intervention cost had only minor impact on societal costs. The conclusion was that an intervention targeting bathing disability among older people presents a cost-effective use of resources and leads to both QALY gains and reduced societal costs over 8 years.

Dementia-specific quality of life instruments: a conceptual analysis

BACKGROUND

Over the past 20 years, many researchers have worked in developing various methods for measuring quality of life (QoL) of people with dementia. The aim of this review is to develop the conceptual frameworks of the dementia-specific QoL instruments, to identify their evolution over time and to provide elements of reflection on the QoL concept in dementia and its evaluation.

METHODS

An electronic search was conducted on PsycINFO and MEDLINE databases, from January 1985 to June 2015 using a combination of key words that include QoL, dementia, and review.

RESULTS

The analysis of the conceptual frameworks of the 18 selected dementia-specific QoL tools shows a great diversity in: (1) the QoL definitions (e.g. health-related QoL definitions, QoL definitions based on Lawton's work, or similar to this latter); (2) the theoretical QoL models (e.g. Lawton' work and modified Lawton, adaptation, personhood); (3) the domains and dimensions; (4) the way to construct the instrument (e.g. development based on literature, opinion of the experts), and (5) the items' formulation (e.g. use of criterion of intensity or frequency).

CONCLUSIONS

There are different conceptual frameworks in the dementia-specific QoL measures with improvements over time (e.g. inclusion of interesting concepts such as adaptation, taking into account the views of patients themselves). Each of the conceptual parameters (definitions, models, domains, and dimensions) is discussed to identify the scales that are conceptually the strongest. Through their review, recommendations for future instrument refinement and development are discussed and a new QoL definition is proposed.

Quality of Life and Utility Measurement in a Large Clinical Trial Sample of Patients with Mild to Moderate Alzheimer's Disease: Determinants and Level of Changes Observed

OBJECTIVE

To evaluate the performance (in terms of responsiveness to change, associations with other criterion standards, and indicators of Alzheimer's disease [AD] severity) of a quality-of-life measure (Quality of Life in Alzheimer's Disease [QOL-AD]) and a health utility measure (Health Utilities Index Mark 3 [HUI-3]) from two recently completed clinical trials of a new drug for AD.

METHODS

Change from baseline scores was calculated, and treatment effects were analyzed using mixed models for repeated measures. Three separate models were then estimated to examine the association between the quality-of-life/utility end points and the clinical and other health outcome end points measured during the trials, including cognition, function, behavior, and dependence.

RESULTS

The performance of the two measures differed. Subject-assessed QOL-AD was found to be weakly associated with clinical measures of cognition, and with caregiver reports of function, behavior, and dependence, and showed little movement over time and did not appear to differ by baseline AD severity. Proxy-assessed QOL-AD scores were consistently lower than subject-assessed scores, and the level of decline in QOL-AD was greater using proxy-assessed QOL-AD. Proxy-assessed HUI-3 scores were more strongly associated with clinical measures of cognition, function, behavior, and dependence than the subject- and proxy-assessed QOL-AD scores. Larger proportionate changes over 78 weeks were observed with HUI-3 scores and greater separation in HUI-3 scores by baseline severity.

CONCLUSIONS

Subject-assessed QOL-AD is less likely than proxy-assessed QOL-AD to respond to changes in clinical measures used to track progression in clinical trials of subjects with mild to moderate AD. Proxy-assessed HUI-3 assessments were more in line with other outcome assessments and could therefore be better outcome measures to evaluate clinical progression in mild to moderate AD.

Adapted Bland-Altman method was used to compare measurement methods with unequal observations per case

OBJECTIVES

To describe an adjustment of the Bland-Altman approach to evaluate possible patterns of discord between two measurement methods with an unequal number of observations per case.

STUDY DESIGN AND SETTING

Two methods of adaptation were compared using self-assessed general well-being scores (one individual rater) and scores given by multiple external raters for illustration. Both empirical data derived from the Older Person's Relevant Outcome of Care Score study and simulated data were used.

RESULTS

When the mean of a number of assessments [X] is compared with a single assessment [Y], the variation [X - Y] (vertical axis) will be correlated with the mean of X and Y (horizontal axis) because the means of scores given by a larger group of raters tend to be less extreme than the scores given by individual raters. In contrast, in the absence of discord patterns, the variation [X - Y] will not be correlated with the mean of all observations Xi and Yj made irrespective of who made them as denominator in the Bland-Altman plot. Thus, the second approach should be used for the valuation.

CONCLUSION

The Bland-Altman approach needs correct adaptations, else artificial biases may occur.

The agreement between proxy and self-completed EQ-5D for care home residents was better for index scores than individual domains

Objective

Proxy measures are an alternative source of data for care home residents who are unable to complete the health utility measure, but the agreement levels between residents and care home staff for the EQ-5D have not been investigated previously. The objective of the present study was to examine the inter-rater agreement levels for the reporting of EQ-5D by care home residents and staff, adjusting for the impact of clustering.

Study Design and Setting

The data consist of EQ-5D scores for 565 pairs of care home residents and proxies and quality-adjusted life-years (QALYs) for 248 pairs. Cluster-adjusted agreement was compared for the domains, index scores, and QALYs from the EQ-5D. Factors influencing index score agreement are also described.

Results

The results show poor to fair agreement at the domain level (cluster-adjusted Kappa −0.03 to 0.26) and moderate agreement at the score level (cluster-adjusted intra-class correlation coefficient [ICC] 0.44–0.50) and for QALYs (cluster-adjusted ICC 0.59). A higher likelihood of depression and lower cognitive impairment were both associated with smaller discrepancy between proxy and self-completed scores.

Conclusion

Proxies appear to be an acceptable source of data for index scores and QALYs but may be less reliable if individual domains are considered.

Health economic evaluation of treatments for Alzheimer's disease: impact of new diagnostic criteria

The socio-economic impact of Alzheimer's disease (AD) and other dementias is enormous, and the potential economic challenges ahead are clear given the projected future numbers of individuals with these conditions. Because of the high prevalence and cost of dementia, it is very important to assess any intervention from a cost-effectiveness viewpoint. The diagnostic criteria for preclinical AD suggested by the National Institute on Aging and Alzheimer's Association workgroups in combination with the goal of effective disease-modifying treatment (DMT) are, however, a challenge for clinical practice and for the design of clinical trials. Key issues for future cost-effectiveness studies include the following: (i) the consequences for patients if diagnosis is shifted from AD-dementia to predementia states, (ii) bridging the gap between clinical trial populations and patients treated in clinical practice, (iii) translation of clinical trial end-points into measures that are meaningful to patients and policymakers/payers and (iv) how to measure long-term effects. To improve cost-effectiveness studies, long-term population-based data on disease progression, costs and outcomes in clinical practice are needed not only in dementia but also in predementia states. Reliable surrogate end-points in clinical trials that are sensitive to detect effects even in predementia states are also essential as well as robust and validated modelling methods from predementia states that also take into account comorbidities and age. Finally, the ethical consequences of early diagnosis should be considered.

Health utility scores in Alzheimer's disease: differences based on calculation with American and Canadian preference weights

OBJECTIVE

Health utility scores quantify health-related quality-of-life (HRQOL) in Alzheimer's disease (AD). These scores are calculated by using preference weights derived from general population samples. We recruited persons with AD and their primary informal caregivers and examined differences in health utility scores calculated by using two sets of published preference weights.

METHODS

We recruited participants from nine clinics across Canada and administered the EuroQol five-dimensional (EQ-5D) questionnaire HRQOL instrument. We converted participants' EQ-5D questionnaire responses into two sets of health utility scores by using US and Canadian preference weights. We assessed agreement between sets by using the intraclass correlation coefficient. Bland-Altman plots depicted individual-level differences between sets.

RESULTS

For 216 persons with AD and their caregivers, mean health utility scores were higher when calculated with US instead of Canadian preference weights (P < 0.0001). The intraclass correlation coefficient (95% CI) was 0.79 (0.05-0.93) in the persons with AD group and 0.83 (0.30-0.94) in the caregiver group. Ninety-five percent of the individual differences in utility score fell between -0.16 and 0.03 for persons with AD and -0.15 and 0.05 for caregivers. Forty-three percent of these differences exceeded a minimum clinically important threshold of 0.074.

CONCLUSIONS

In AD studies, researchers should calculate health utility scores by using preference weights obtained in the general population of their country of interest. Using weights from other countries' populations could bias the utilities and adversely affect the results of economic evaluations of AD treatments.

Estimated quality-adjusted life-year associated with the degree of activities of daily living in patients with Alzheimer's disease

BACKGROUND/AIMS

The quality-adjusted life-year (QALY) and health state utility values (HSUVs) are major quality of life scales that are used for the analyses of health economics of diseases such as Alzheimer's disease (AD). In Japan, the most common dementia disease is AD with cerebrovascular diseases (CVD), followed by 'pure' AD. There is a need to reconsider QALY and HSUVs in the context of activities of daily living (ADL) levels in AD and AD with CVD.

METHODS

Studies on QALY and HSUVs based on ADL levels in AD were identified using a PubMed search. HSUVs were estimated in AD patients with ADL levels A (independent walking and eating), B (some problems with walking but sitting without assistance), and C (confined to bed). These three ADL levels correspond approximately to the stages of Mobility on the EQ-5D.

RESULTS

There has been no previous report on HSUVs related to the level of physical activity of patients with AD. From the previous reports and EQ-5D, we estimated that the HSUVs of pure AD and AD with CVD for ADL levels A, B, and C were 0.61 and 0.58, 0.53 and 0.28, and 0.19 and 0.05, respectively.

CONCLUSION

Effects of ADL should be considered during the decision making process in health policy for dementia care in Japan.

The estimation of utility weights in cost-utility analysis for mental disorders: a systematic review

OBJECTIVE

To systematically review approaches and instruments used to derive utility weights in cost-utility analyses (CUAs) within the field of mental disorders and to identify factors that may have influenced the choice of the approach.

METHODS

We searched the databases DARE (Database of Abstracts of Reviews of Effects), NHS EED (National Health Service Economic Evaluation Database), HTA (Health Technology Assessment), and PubMed for CUAs. Studies were included if they were full economic evaluations and reported quality-adjusted life-years as the health outcome. Study characteristics and instruments used to estimate utility weights were described and a logistic regression analysis was conducted to identify factors associated with the choice of either the direct (e.g. standard gamble) or the preference-based measure (PBM) approach (e.g. EQ-5D).

RESULTS

We identified 227 CUAs with a maximum in 2009, 2010, and 2012. Most CUAs were conducted in depression, dementia, or psychosis, and came from the US or the UK, with the EQ-5D being the most frequently used instrument. The application of the direct approach was significantly associated with depression, psychosis, and model-based studies. The PBM approach was more likely to be used in recent studies, dementia, Europe, and empirical studies. Utility weights used in model-based studies were derived from only a small number of studies.

LIMITATIONS

We only searched four databases and did not evaluate the quality of the included studies.

CONCLUSIONS

Direct instruments and PBMs are used to elicit utility weights in CUAs with different frequencies regarding study type, mental disorder, and country.

Lipid raft disarrangement as a result of neuropathological progresses: a novel strategy for early diagnosis?

Lipid rafts are the preferential site of numerous membrane signaling proteins which are involved in neuronal functioning and survival. These proteins are organized in multiprotein complexes, or signalosomes, in close contact with lipid classes particularly represented in lipid rafts (i.e. cholesterol, sphingolipids and saturated fatty acids), which may contribute to physiological responses leading to neuroprotection. Increasing evidence indicates that alteration of lipid composition in raft structures as a consequence of neuropathologies, such as Alzheimer's disease (AD) and Parkinson's disease (PD), causes a dramatic increase in lipid raft order. These phenomena may correlate with perturbation of signalosome activities, likely contributing to neurodegenerative progression. Interestingly, significant disruption of stable raft microenvironments has been already observed in the first stages of either AD or PD, suggesting that these alterations may represent early events in the neuropathological development. In this regard, the search for biochemical markers, such as specific metabolic products altered in the brain at the first steps of the disease, presently represents an important challenge for early diagnostic strategies. Alterations of these biomarkers may be reflected in either plasma or cerebrospinal fluid, thus representing a potential strategy to predict an accurate diagnosis. We propose that pathologically-linked lipid raft markers may be interesting candidates to be explored at this level, although it has not been studied so far to what extent alteration of different signalosome components may be reflected in peripheral fluids. In this mini-review, we will discuss on relevant aspects of lipid rafts that contribute to the modulation of neuropathological events related to AD and PD. An interesting hypothesis is that anomalies on raft biomarkers measured at peripheral fluids might mirror the lipid raft pathology observed in early stages of AD and PD.

Evaluating the cost effectiveness of donepezil in the treatment of Alzheimer's disease in Germany using discrete event simulation

BACKGROUND

Previous cost-effectiveness studies of cholinesterase inhibitors have modeled Alzheimer's disease (AD) progression and treatment effects through single or global severity measures, or progression to "Full Time Care". This analysis evaluates the cost-effectiveness of donepezil versus memantine or no treatment in Germany by considering correlated changes in cognition, behavior and function.

METHODS

Rates of change were modeled using trial and registry-based patient level data. A discrete event simulation projected outcomes for three identical patient groups: donepezil 10 mg, memantine 20 mg and no therapy. Patient mix, mortality and costs were developed using Germany-specific sources.

RESULTS

Treatment of patients with mild to moderately severe AD with donepezil compared to no treatment was associated with 0.13 QALYs gained per patient, and 0.01 QALYs gained per caregiver and resulted in average savings of €7,007 and €9,893 per patient from the healthcare system and societal perspectives, respectively. In patients with moderate to moderately-severe AD, donepezil compared to memantine resulted in QALY gains averaging 0.01 per patient, and savings averaging €1,960 and €2,825 from the healthcare system and societal perspective, respectively.In probabilistic sensitivity analyses, donepezil dominated no treatment in most replications and memantine in over 70% of the replications. Donepezil leads to savings in 95% of replications versus memantine.

CONCLUSIONS

Donepezil is highly cost-effective in patients with AD in Germany, leading to improvements in health outcomes and substantial savings compared to no treatment. This holds across a variety of sensitivity analyses.