Cost-effectiveness of memantine for moderate to severe Alzheimer's disease in Sweden

Present Algorithms and Future Treatments for Alzheimer's Disease

An estimated 47 million people live with Alzheimer’s disease (AD) and other forms of dementia worldwide. Although no disease-modifying treatments are currently available for AD, earlier diagnosis and proper management of the disease could have considerable impact on patient and caregiver quality of life and functioning. Drugs currently approved for AD treat the cognitive, behavioral, and functional symptoms of the disease and consist of three cholinesterase inhibitors (ChEIs) and the N-methyl-D-aspartate receptor antagonist memantine. Treatment of patients with mild to moderate AD is generally initiated with a ChEI. Patients who show progression of symptoms while on ChEI monotherapy may be switched to another ChEI and/or memantine can be added to the treatment regimen. In recent years, putative disease-modifying therapies have emerged that aim to slow the progression of AD instead of only addressing its symptoms. However, many therapies have failed in clinical trials in patients with established AD, suggesting that, once developed, disease-modifying agents may need to be deployed earlier in the course of illness. The goal of this narrative literature review is to discuss present treatment algorithms and potential future therapies in AD.

Family and Caregiver Spillover Effects in Cost-Utility Analyses of Alzheimer's Disease Interventions

BACKGROUND AND OBJECTIVE

Alzheimer's disease or dementia can impose a significant burden on family and other informal caregivers. This study investigated how the inclusion of family/informal caregiver spillover effects in a cost-utility analysis may influence the reported value of Alzheimer's disease/dementia interventions.

METHODS

We used PubMed to identify Alzheimer's disease or dementia cost-utility analyses published from 1 January, 2000 to 31 March, 2018. We reviewed and abstracted information from each study using a two-reader consensus process. We investigated the frequency and methods in which family/caregiver spillover costs and health effects were incorporated into cost-utility analyses, and examined how their inclusion may influence the reported incremental cost-effectiveness ratios.

RESULTS

Of 63 Alzheimer's disease/dementia cost-utility analyses meeting inclusion criteria, 44 (70%) considered at least some family/caregiver spillover costs or health effects. Thirty-two studies incorporated spillover costs only, two incorporated spillover health effects only, and ten incorporated both. The most common approach for accounting for spillover was adding informal caregiving time costs to patient costs (n = 36) and adding informal caregiver quality-adjusted life-years to patient values (n = 7). In a subset of 33 incremental cost-effectiveness ratio pairs from 19 studies, incorporating spillover outcomes made incremental cost-effectiveness ratios more favorable (n = 15; 45%) or kept the intervention cost saving (n = 13; 39%) in most cases. In fewer cases, including spillover increased incremental cost-effectiveness ratios (n = 2; 6%), kept the intervention dominated [more costs/less quality-adjusted life-years] (n = 2; 6%), or changed incremental cost-effectiveness ratio from dominated to less cost/less quality-adjusted life-years (n = 1; 3%). In 11 cases (33%), adding spillover effects into analyses resulted in a lower incremental cost-effectiveness ratio that crossed a common cost-effectiveness threshold, which could have downstream implications for programs or policies that are adopted based on cost-effectiveness analysis results.

DISCUSSION

Most Alzheimer's disease/dementia cost-utility analyses incorporated spillover costs, often as caregiver time costs, but considered spillover health impacts less often. In about 85% of the analyses, including Alzheimer's disease/dementia spillover cost or health effects decreased incremental cost-effectiveness ratios or kept the intervention cost saving. The broader value of an Alzheimer's disease/dementia intervention to society may in some cases be underestimated without considering these spillover effects on family and informal caregivers.

A systematic review of economic evaluations of the use of memantine alone or combined with donepezil for moderate to severe Alzheimer’s disease

Abstract Objective: To synthesize the available evidence and state of the art of economic evaluations which evaluate the use of memantine, whether alone or combined with donepezil, for moderate to severe Alzheimer’s disease (AD), focusing on the analytical decision models built. Method: The electronic databases MEDLINE, EMBASE, NHS EED, CEA Registry and LILACS were searched for references. After duplicates were removed, two independent reviewers evaluated the titles and abstracts and subsequently the full texts. The Drummond M. tool was used to evaluate the quality of the studies. Results: After the application of the eligibility criteria, twelve complete economic evaluations were included. One evaluation was a clinical trial, two involved simulations and nine used Markov models. The main outcome measure adopted was dominated by cost per quality adjusted life year (QALY). The use of memantine was considered cost-effective and dominant in eight studies; while in a single study, its use was dominated when compared to donepezil for moderate AD. Sensitivity analyzes were systematically performed, with robust results. The quality assessment indicated that the methodological quality of the studies was good. Conclusion: Although there is some controversy regarding the benefits derived from the use of memantine, whether combined or not with donepezil, the evidence collected suggests that it is cost-effective in the countries where the studies were performed. However, local economic studies need to be performed, given the significant variability derived from the different parameters adopted in the evaluations.

Where are we at with model-based economic evaluations of interventions for dementia? a systematic review and quality assessment

ABSTRACTObjective:To identify, review, and critically appraise model-based economic evaluations of all types of interventions for people with dementia and their carers.

DESIGN

A systematic literature search was undertaken to identify model-based evaluations of dementia interventions. A critical appraisal of included studies was carried out using guidance on good practice methods for decision-analytic models in health technology assessment, with a focus on model structure, data, and model consistency.

SETTING

Interventions for people with dementia and their carers, across prevention, diagnostic, treatment, and disease management.

RESULTS

We identified 67 studies, with 43 evaluating pharmacological products, 19 covering prevention or diagnostic strategies, and 5 studies reporting non-pharmacological interventions. The majority of studies use Markov models with a simple structure to represent dementia symptoms and disease progression. Half of all studies reported taking a societal perspective, with the other half adopting a third-party payer perspective. Most studies follow good practices in modeling, particularly related to the decision problem description, perspective, model structure, and data inputs. Many studies perform poorly in areas related to the reporting of pre-modeling analyses, justifying data inputs, evaluating data quality, considering alternative modeling options, validating models, and assessing uncertainty.

CONCLUSIONS

There is a growing literature on the model-based evaluations of interventions for dementia. The literature predominantly reports on pharmaceutical interventions for Alzheimer's disease, but there is a growing literature for dementia prevention and non-pharmacological interventions. Our findings demonstrate that decision-makers need to critically appraise and understand the model-based evaluations and their limitations to ensure they are used, interpreted, and applied appropriately.

A pharmacoeconomic evaluation of cholinesterase inhibitors and memantine for the treatment of Alzheimer's disease

INTRODUCTION

Alzheimer's disease (AD) results in progressively worsening cognitive decline, leading to loss of functional ability, behavior/mood disturbances, institutionalization, and death. Current pharmaceutical therapies only treat the symptoms of cognitive decline yet can be expensive for payers. Areas covered: The authors undertook a systematic review of economic evaluations of pharmaceutical therapies for AD. The literature search encompassed English-language studies indexed in PubMed (Medline), Cochrane Library Current, and Web of Science. The search included articles published between 1 January 1995 and 10 February 2018. The literature suggested AD medications generally dominated comparator treatments (e.g. placebo). Expert opinion: The authors noted several limitations of the included economic evaluations. These limitations suggest the results of the economic evaluations should be interpreted with caution. Many economic models were not transparent with respect to sources of probabilities and cost data, and data collected in certain jurisdictions were applied to other jurisdictions without considering the validity of such applications. Measuring health utilities in cognitively impaired populations raises questions about the validity of quality-adjusted life years, but this issue was unaddressed in the included studies. Most included studies were sponsored by industry and the results tended to overwhelmingly support the manufacturer's product.

Systematic Review of Model-Based Economic Evaluations of Treatments for Alzheimer's Disease

BACKGROUND

Numerous economic evaluations using decision-analytic models have assessed the cost effectiveness of treatments for Alzheimer's disease (AD) in the last two decades. It is important to understand the methods used in the existing models of AD and how they could impact results, as they could inform new model-based economic evaluations of treatments for AD.

OBJECTIVE

The aim of this systematic review was to provide a detailed description on the relevant aspects and components of existing decision-analytic models of AD, identifying areas for improvement and future development, and to conduct a quality assessment of the included studies.

METHODS

We performed a systematic and comprehensive review of cost-effectiveness studies of pharmacological treatments for AD published in the last decade (January 2005 to February 2015) that used decision-analytic models, also including studies considering patients with mild cognitive impairment (MCI). The background information of the included studies and specific information on the decision-analytic models, including their approach and components, assumptions, data sources, analyses, and results, were obtained from each study. A description of how the modeling approaches and assumptions differ across studies, identifying areas for improvement and future development, is provided. At the end, we present our own view of the potential future directions of decision-analytic models of AD and the challenges they might face.

RESULTS

The included studies present a variety of different approaches, assumptions, and scope of decision-analytic models used in the economic evaluation of pharmacological treatments of AD. The major areas for improvement in future models of AD are to include domains of cognition, function, and behavior, rather than cognition alone; include a detailed description of how data used to model the natural course of disease progression were derived; state and justify the economic model selected and structural assumptions and limitations; provide a detailed (rather than high-level) description of the cost components included in the model; and report on the face-, internal-, and cross-validity of the model to strengthen the credibility and confidence in model results. The quality scores of most studies were rated as fair to good (average 87.5, range 69.5-100, in a scale of 0-100).

CONCLUSION

Despite the advancements in decision-analytic models of AD, there remain several areas of improvement that are necessary to more appropriately and realistically capture the broad nature of AD and the potential benefits of treatments in future models of AD.

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.

Evolution of the evidence on the effectiveness and cost-effectiveness of acetylcholinesterase inhibitors and memantine for Alzheimer's disease: systematic review and economic model

INTRODUCTION

in 2007 the National Institute of Health and Clinical Excellence (NICE) restricted the use of acetylcholinesterase inhibitors and memantine.

METHODS

we conducted a health technology assessment (HTA) of the effectiveness and cost-effectiveness of donepezil, galantamine, rivastigmine and memantine for the treatment of AD to re-consider and up-date the evidence base used to inform the 2007 NICE decision. The systematic review of effectiveness targeted randomised controlled trials. A comprehensive search, including MEDLINE, Embase and the Cochrane Library, was conducted from January 2004 to March 2010. All key review steps were done by two reviewers. Random effects meta-analysis was conducted. The cost-effectiveness was assessed using a cohort-based model with three health states: pre-institutionalised, institutionalised and dead. The perspective was NHS and Personal Social Services and the cost year 2009.

RESULTS

confidence about the size and statistical significance of the estimates of effect of galantamine, rivastigmine and memantine improved on function and global impact in particular. Cost-effectiveness also changed. For donepezil, galantamine and rivastigmine, the incremental cost per quality-adjusted life year (QALY) in 2004 was above £50,000; in 2010 the same drugs 'dominated' best supportive care (improved clinical outcome at reduced cost). This was primarily because of changes in the modelled costs of introducing the drugs. For memantine, the cost-effectiveness also improved from a range of £37-53,000 per QALY gained to a base-case of £32,000.

CONCLUSION

there has been a change in the evidence base between 2004 and 2010 consistent with the change in NICE guidance. Further evolution in cost-effectiveness estimates is possible particularly if there are changes in drug prices.

Systematic review of economic evaluations of Alzheimer's disease medications

This systematic review was conducted to summarize published pharmacoeconomic studies of Alzheimer's disease (AD) medications. Pharmacoeconomic studies were included in the review if they were published in English and contained a full and complete report of an original economic evaluation. The studies also had to be comparative in nature (i.e., cost-benefit, cost-effectiveness, cost-utility or cost-minimization analyses). Existing AD medications were found to dominate standard treatment (i.e., no drugs), or they were found to be more costly and more effective than standard treatment. Estimates of cost and effect varied widely because of different underlying models, assumptions and data sources. More research is needed to draw firmer conclusions regarding the overall cost-effectiveness of AD medications.

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

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

Cost-effectiveness of memantine in moderate and severe Alzheimer's disease in Norway

BACKGROUND

The cost-effectiveness of memantine for the treatment of moderate and severe Alzheimer's disease has been assessed in several European countries. Objective of the study was to assess it in Norwegian settings.

METHODS

This cost-utility analysis used a Markov modelling approach to simulate the evolution of patients until their need for full-time care (FTC) over a 5-year period. FTC was defined as a patient becoming either dependent or institutionalised. Transition probabilities were estimated using a newly developed predictive equation of time to FTC. Health resource use and utilities were obtained from the Scandinavian Study of Cost and Quality of Life in Alzheimer's Disease study, and mortality was obtained from the Oslo study. Memantine efficacy was based on a meta-analysis of six large trials. The model compared memantine with its alternative in this population, that is no pharmacological treatment or background therapy with acetylcholinesterase inhibitors. The model underwent extensive sensitivity analyses.

RESULTS

In Norway, memantine was found to delay the need for FTC by 4.4 weeks compared with standard care and was associated with increased quality-adjusted life years. Memantine was the dominant strategy with cost savings of €3739 (30 041 NOK) per patient. The probability of being the dominant strategy was 98.8%. This result was confirmed across multiple sensitivity analyses.

CONCLUSIONS

The model suggests that memantine prolongs time to FTC for no additional cost to the healthcare system and society. It can be regarded as a cost-effective choice in the management of moderate and severe Alzheimer's disease.

Model-based economic evaluation in Alzheimer's disease: a review of the methods available to model Alzheimer's disease progression

OBJECTIVE

To consider the methods available to model Alzheimer's disease (AD) progression over time to inform on the structure and development of model-based evaluations, and the future direction of modelling methods in AD.

METHODS

A systematic search of the health care literature was undertaken to identify methods to model disease progression in AD. Modelling methods are presented in a descriptive review.

RESULTS

The literature search identified 42 studies presenting methods or applications of methods to model AD progression over time. The review identified 10 general modelling frameworks available to empirically model the progression of AD as part of a model-based evaluation. Seven of these general models are statistical models predicting progression of AD using a measure of cognitive function. The main concerns with models are on model structure, around the limited characterization of disease progression, and on the use of a limited number of health states to capture events related to disease progression over time. None of the available models have been able to present a comprehensive model of the natural history of AD.

CONCLUSIONS

Although helpful, there are serious limitations in the methods available to model progression of AD over time. Advances are needed to better model the progression of AD and the effects of the disease on peoples' lives. Recent evidence supports the need for a multivariable approach to the modelling of AD progression, and indicates that a latent variable analytic approach to characterising AD progression is a promising avenue for advances in the statistical development of modelling methods.

The pharmacoeconomics of cognitive enhancers in moderate to severe Alzheimer's disease

Alzheimer's disease is associated with a substantial economic impact on patients, their caregivers and society. Due to the current rise in the aging population, the prevalence and impact of Alzheimer's disease are expected to increase greatly. The cost of caring for someone with Alzheimer's disease is magnified in the more severe stages of the disease. There are four cognitive enhancers commonly used for the treatment of Alzheimer's disease: three cholinesterase inhibitors (donepezil, rivastigmine and galantamine) and one NMDA receptor antagonist (memantine). Of these, donepezil and memantine have been approved in many countries as pharmacological treatments for moderate to severe Alzheimer's disease, while donepezil, rivastigmine and galantamine are approved treatments for mild to moderate Alzheimer's disease. While cost effectiveness has been well studied in mild to moderate Alzheimer's disease, the cost-benefit information for drug therapy in moderate to severe Alzheimer's disease is less clear. This article reviews the pharmacoeconomic data available on these four drugs, with a specific focus on moderate to severe Alzheimer's disease, including economic burden, cost drivers, clinical outcomes and pharmacoeconomic studies. A key driver of the cost of Alzheimer's disease is the severity of the disease, indicating that the ability to stabilize the disease state is a potential source of cost savings. Drug therapies that can limit increases in behavioural problems and cognitive and functional impairment, and postpone institutionalization without an increase in longevity may serve to reduce the economic burden on Alzheimer's disease patients. The data suggest that, while the available, approved agents offer only modest improvements in clinical outcomes, they could be cost-effective treatments for moderate to severe Alzheimer's disease when viewed from the societal perspective. For memantine and donepezil, data are available that suggest that the cost of these drugs is offset by the clinical and societal benefits provided by slowing the progression of Alzheimer's disease. While there are few head-to-head comparison trials, the similarity in costs of the treatments and efficacy against placebo suggest that cost effectiveness will not be substantially different among treatments. More studies that examine longitudinal resource utilization and its relationship to drug treatment in the moderate to severe stages are needed to clarify cost benefit in this population and possibly differentiate between individual medications.

Spotlight on memantine in moderate to severe Alzheimer's disease

Memantine (Axura, Ebixa, Namenda) is an uncompetitive, moderate-affinity NMDA receptor antagonist that is indicated for the treatment of moderate to severe Alzheimer's disease. In well designed trials in patients with moderate to severe Alzheimer's disease, oral memantine monotherapy improved outcomes in the area of functional ability more than placebo in one trial, but in a second trial, treatment differences did not reach significance. Memantine has a distinct mode of action compared with that of acetylcholinesterase (AChE) inhibitors, and in a well designed study, combination therapy with memantine plus donepezil improved outcomes more than donepezil plus placebo in all four domains (function, cognition, behaviour and global change). Memantine is generally well tolerated, with adverse events occurring with a similar incidence to that reported with placebo. In modelled cost-effectiveness analyses, memantine was dominant to no therapy in regard to cost per quality-adjusted life-year (QALY) gained, and the combination of memantine plus donepezil was dominant to donepezil therapy alone in regard to QALYs gained when treatment periods exceeded 1 year in patients with moderate to severe disease. Thus, in the management of patients with moderate to severe Alzheimer's disease, memantine provides an effective treatment option. To date, clinical trial support is greater for memantine use in combination with an AChE inhibitor, while more data are needed to confirm its efficacy as monotherapy.

Predicting time to full-time care in AD: a new model

OBJECTIVE

To develop a model to predict the length of time before patients with Alzheimer's disease (AD) of varying severity require full-time care (FTC).

METHODS

A predictive model (equation) of time to FTC (defined as being institutionalised or dependent) was developed based on the London and South-East Region (LASER-AD) epidemiological study using a discrete time representation of the Cox continuous time proportional hazards model and complementary log-log specification.

RESULTS

Of the 117 pre-FTC patients, 68 (58.1%) patients progressed to FTC during the 54-month follow-up period. Analysis of potential predictors showed that baseline cognitive state, impairment of activities of daily living (ADL) and neuropsychiatric symptoms were strong predictors of time to FTC. In addition, the rate of cognitive and ADL decline predicted time to FTC. The final model predicted 88.2% of observations.

CONCLUSION

The model simulates and predicts progression of pre-FTC AD patients until the need for FTC based on assessments for cognitive, functional and behavioural domains. The main application of the model is to assess the cost effectiveness of AD therapies as potential adjuncts to a background AD treatment including disease-modifying treatments. The applicability of the predictive model to a specific setting should be carefully assessed, i.e. the patient population being examined should have similar characteristics as patients in the LASER-AD cohort.

Commentary on "Health economics and the value of therapy in Alzheimer's disease." Cost-effectiveness studies

The high prevalence of dementia has a great impact on the formal care systems as well as on the situation for informal caregivers. Thus the question of cost effectiveness is crucial. This paper is based on the health-economic portion of the dementia project of the Swedish Council on Technology Assessment in Healthcare. After a database search and quality judgment of papers, 35 papers were included (22 were pharmacoeconomic studies, and 13 focused on programs, such as daycare, caregiver support, and living arrangements). No empirical drug study was regarded as a complete health-economic study. Of the four prospective, randomized, controlled trials, three yielded a nonsignificant difference regarding costs (all for donepezil), whereas there was a significant cost reduction in the Memantine study (favoring Memantine treatment), mainly due to reduction in caregiver time. The majority of the complete pharmacoeconomic modeling studies showed a dominance for drug treatment, indicating cost effectiveness. In conclusion, as regards the cost effectiveness of treatment for Alzheimer's disease, no evidence could be stated in terms of empirical studies, mainly because of a lack of studies. Although most models indicated cost effectiveness, the Swedish Council on Technology Assessment in Healthcare did not regard this as sufficient evidence of cost effectiveness. There is a need for larger and longer empirical studies, and for enlarged sensitivity analyses, in terms of model studies.

Critical appraisal of the long-term impact of memantine in treatment of moderate to severe Alzheimer's disease

Alzheimer's disease is the most common cause of dementia in older adults. The clinical features include progressive memory decline as well as cognitive deficits with executive dysfunction, language, visual perceptual difficulties, apraxia and agnosia. During the moderate to severe stage of the disease, there is a major decline in memory and function, while neuropsychiatric disturbances often emerge and patients become difficult to manage. These distressing symptoms increase caregiver burden and add to the direct costs of care of the patients. Any improvements in patient function and behavioral symptoms can reduce caregiver burden. Memantine has been available for a number of years in Europe and in North America. In this article, we examine the pharmacological rationale for its use, and the current clinical evidence for its efficacy and long-term effectiveness in the management of cognitive and behavioral symptoms in moderate to severe stages of Alzheimer's disease.

Memantine: a review of its use in moderate to severe Alzheimer's disease

Memantine is an uncompetitive, moderate-affinity NMDA receptor antagonist that is indicated for the treatment of moderate to severe Alzheimer's disease. In well designed trials in patients with moderate to severe Alzheimer's disease, oral memantine monotherapy improved outcomes in the area of functional ability more than placebo in one trial, but in a second trial, treatment differences did not reach significance. Memantine has a distinct mode of action compared with that of acetylcholinesterase (AChE) inhibitors, and in a well designed study, combination therapy with memantine plus donepezil improved outcomes more than donepezil plus placebo in all four domains (function, cognition, behaviour and global change). Memantine is generally well tolerated, with adverse events occurring with a similar incidence to that reported with placebo. In modelled cost-effectiveness analyses, memantine was dominant to no therapy in regard to cost per quality-adjusted life-year (QALY) gained, and the combination of memantine plus donepezil was dominant to donepezil therapy alone in regard to QALYs gained when treatment periods exceeded 1 year in patients with moderate to severe disease. Thus, in the management of patients with moderate to severe Alzheimer's disease, memantine provides an effective treatment option. To date, clinical trial support is greater for memantine use in combination with an AChE inhibitor, while more data are needed to confirm its efficacy as monotherapy.

The cost of dementia in Europe: a review of the evidence, and methodological considerations

Alzheimer's disease (AD) is a leading cause of disability in the elderly, leading to a high burden on caregivers and costs to society. This article describes the current level of data availability regarding the costs of AD in Europe, summarizes and compares findings from previous studies in different countries, and discusses the applicability of available data for modelling purposes. A literature review was conducted for papers in any language reporting data on costs of care for patients with diagnosed dementia or possible/probable AD. Only papers reporting patient-level data on costs were included. A total of 16 studies were identified: from the Nordic region (4), the UK (3), Spain (3), France (2), Italy (2), Belgium (1) and Germany (1). There is large variation in total cost estimates, depending on, for example, differences in study methodology, setting, type and severity of patients included, range of costs assessed and the choice of principle for valuing informal care. The median value for total annual care costs in all studies was Euro28 000 (range Euro6614-Euro64 426) [year 2005 values]. Few studies assessed aspects of disease severity other than cognitive function. The costs of AD in Europe are substantial and increase with disease severity. Methodological differences between studies make comparison across countries and healthcare systems difficult, and there is a need to standardize methods for assessing and valuing informal care. Patient-level information on resource use is required to analyse determinants of care costs and predict the impact of therapeutic interventions. More data are needed to support future economic evaluations of therapies for AD.

Update on the use of memantine in Alzheimer's disease

Memantine is a low to moderate affinity N-methyl-D-aspartate receptor (NMDAR) antagonist. The effects of memantine in Alzheimer's disease (AD) have been studied in 7 randomized controlled trials in many post-hoc analyses. Three out of four RCTs in patients with moderate to severe AD (Mini Mental State Examination [MMSE] <14) showed a statistically significant but clinically small positive effect of memantine on cognition, global functioning, activities of daily living (ADL) and neuropsychiatric symptoms. No effects on these outcome measures could be found in the three RCTs studying patients with mild to moderate AD (MMSE 14-24). Two of these studies evaluated the effect of addition of memantine to donepezil. Only the study in patients with mild to moderate AD showed a positive effect of addition of memantine on cognition, ADL, global functioning and neuropsychiatric functioning. Cost-effectiveness of memantine therapy remains controversial. Post-hoc analyses and observational studies suggest some effects on agitation/aggression, delusions or hallucinations. Side effects of memantine are usually mild and seem to be comparable with placebo. In this review, an oversight of pharmacodynamics and pharmacokinetics of memantine is presented. Also, published data concerning efficacy and safety in patients with AD are presented.

Decision analytic models for Alzheimer's disease: state of the art and future directions

Decision analytic policy models for Alzheimer's disease (AD) enable researchers and policy makers to investigate questions about the costs and benefits of a wide range of existing and potential screening, testing, and treatment strategies. Such models permit analysts to compare existing alternatives, explore hypothetical scenarios, and test the strength of underlying assumptions in an explicit, quantitative, and systematic way. Decision analytic models can best be viewed as complementing clinical trials both by filling knowledge gaps not readily addressed by empirical research and by extrapolating beyond the surrogate markers recorded in a trial. We identified and critiqued 13 distinct AD decision analytic policy models published since 1997. Although existing models provide useful insights, they also have a variety of limitations. (1) They generally characterize disease progression in terms of cognitive function and do not account for other distinguishing features, such as behavioral symptoms, functional performance, and the emotional well-being of AD patients and caregivers. (2) Many describe disease progression in terms of a limited number of discrete states, thus constraining the level of detail that can be used to characterize both changes in patient status and the relationships between disease progression and other factors, such as residential status, that influence outcomes of interest. (3) They have focused almost exclusively on evaluating drug treatments, thus neglecting other disease management strategies and combinations of pharmacologic and nonpharmacologic interventions. Future AD models should facilitate more realistic and compelling evaluations of various interventions to address the disease. An improved model will allow decision makers to better characterize the disease, to better assess the costs and benefits of a wide range of potential interventions, and to better evaluate the incremental costs and benefits of specific interventions used in conjunction with other disease management strategies.

Cost-effectiveness of memantine compared with standard care in moderate-to-severe Alzheimer disease in Canada

OBJECTIVE

To conduct a cost-effectiveness analysis comparing the addition of memantine to standard care (that is, without acetylcholinesterase inhibitors) with standard care alone in moderate-to-severe Alzheimer disease (AD) in Canada.

METHODS

A 2-year Markov model estimated clinical effects in terms of quality-adjusted life years (QALYs) and time in complete dependence as well as societal costs in four 6-month cycles. Health states were defined by AD severity assessed with the Mini-Mental State Examination (moderate = 10 to 19; severe < 10), by level of dependence in activities of daily living, and by death. Transition probabilities were estimated by combining data of patients with moderate-to-severe AD from all relevant clinical trials. QALYs were estimated from a UK epidemiologic study. The initial distribution and use of medical and support services for each health state was obtained from the Canadian Study on Health and Aging with current estimates of frequency of use and unit prices applied.

RESULTS

Compared with standard care, the memantine strategy saved more than 1 month of complete dependence and produced 0.03 additional QALYs, with no additional cost. Probabilistic sensitivity analyses give an 83.3% chance that memantine treatment is cost-neutral, an 89.5% chance of its being cost-effective if the decision maker is willing to pay $20 000 for a QALY, and a 96.2% chance with a willingness to pay $100 000 per QALY. Robustness of results was confirmed through 1-way and scenario-based sensitivity analyses.

CONCLUSIONS

Our evaluation found that memantine monotherapy produced relevant health benefit, compared with standard care alone, with no additional costs. Results are consistent with other economic evaluations of memantine conducted in Europe and the United States.

Cost-effectiveness of memantine in moderate-to-severe Alzheimer's disease patients receiving donepezil

OBJECTIVE

The efficacy and safety of memantine in patients with moderate-to-severe Alzheimer's disease (AD) receiving stable doses of donepezil were recently demonstrated in a phase III trial. The cost-effectiveness of such therapy is unknown.

RESEARCH DESIGN AND METHODS

A microsimulation model was developed to depict AD progression over time and associated clinical and economic outcomes. AD progression was measured in terms of decline in cognitive function, as assessed by the Severe Impairment Battery (SIB). At model entry, patients were assumed to have moderate-to-severe AD, to be on stable doses of donepezil, and to begin combination therapy with memantine, or continue to receive donepezil alone; duration of therapy was assumed to be 1 year. Drug efficacy was based on data from a phase III trial. Key assumptions of the model included: (1) efficacy of study drugs would extend to 1 year; (2) measures of cognitive function could be mapped to one another, as well as to global measures of disease severity; and (3) following therapy discontinuation, cognitive function would revert immediately to natural history levels. Cost-effectiveness was assessed in terms of cost (2005 US$) per quality-adjusted life-year (QALY) gained over a lifetime (3% discount rate).

RESULTS

SIB scores were estimated to improve by 3.3 over 1 year from therapy with memantine plus donepezil (vs. donepezil alone). While pharmacotherapy costs were estimated to increase by $1250 during the year of memantine treatment, costs of formal and informal services were estimated to decrease by $1240 over this period and by $1493 (discounted present value) over a lifetime. Findings were sensitive to the assumed SIB score at therapy initiation; cost-effectiveness was better for patients with higher initial SIB scores (i.e., less severe disease).

CONCLUSION

In patients with moderate-to-severe AD already receiving donepezil, treatment with memantine results in improved clinical outcomes and reduced total costs of care.

Memantine: efficacy and safety in mild-to-severe Alzheimer's disease

Alzheimer's disease (AD) is the most common cause of dementia, accounting for 25 million cases worldwide. Until recently, the pharmacotherapy of AD was limited to the use of cholinesterase inhibitors (ChEIs) that are approved only for the mild to moderate stages of the illness. Memantine, an NMDA receptor antagonist has been found to be effective, both as monotherapy and in combination with donepezil, in the treatment of patients with moderate to severe stage AD. More recent studies have examined the role of memantine in the treatment of the mild to moderate stages of the disease, although the collective results of these studies remain inconclusive. Available pharmacoeconomic data indicate that treatment with memantine is cost-effective when compared with no treatment in patients with moderate to severe AD. Memantine treatment is predicted to be associated with lower costs of care, longer time to dependence and institutionalization, and gains in quality-adjusted life-years. In this article, we review the evidence for the use of memantine in patients with AD, ranging from the mild to severe stages of disease.

Modelling disease progression in Alzheimer's disease: a review of modelling methods used for cost-effectiveness analysis

The literature reporting economic evaluations related to the treatment of Alzheimer's disease (AD) has developed over the last decade. Most analyses have used economic models to estimate the cost effectiveness of drugs for the treatment of AD. This review considers the range of methods used in the published cost-effectiveness literature to model AD progression and the effect of interventions on the progression of AD. The review builds on and updates an earlier systematic review of cost-effectiveness studies on drugs for AD. Systematic and rigorous methods were used to search the literature for economic evaluations estimating the cost effectiveness of donepezil, rivastigmine, galantamine or memantine in AD. The literature search covered a wide range of electronic databases (e.g. MEDLINE, EMBASE), and included literature from the inception of databases up to the end of 2005. The search identified 22 published economic evaluations. An outline and brief critical review of the identified studies is provided, and thereafter the methods used to model disease progression were considered in more detail. The review employs recent guidance on good practice in decision-analytic modelling in HTA to critically review the modelling methods used. Using this guidance, the models are assessed against the broad criteria of model structure, data inputs and assessment of uncertainty and inconsistency. Concerns were noted over the model structure employed in all models. The reliance on cognitive scores to model AD, the progression of the disease, and the effect of treatment on costs and consequences is regarded as a serious limitation in almost all of the studies identified. There are also limitations over the data used to populate published models, especially around the failure of studies to document and establish the basis for the modelling of treatment effects. It is also clear that studies modelling AD progression, and subsequently the cost effectiveness of treatment, have not addressed uncertainty or consistency (internal and/or external) in sufficient detail. Further research is required on more appropriate methods for the modelling of AD progression. In the meantime, future economic evaluations of treatment need to be more explicit on the methods used to model AD, and the data used to populate models.

Memantine: a review of its use in Alzheimer's disease

Memantine (Ebixa, Axura, Namenda, Akatinol) is a moderate-affinity, uncompetitive, voltage-dependent, NMDA-receptor antagonist with fast on/off kinetics that inhibits excessive calcium influx induced by chronic overstimulation of the NMDA receptor. Memantine is approved in the US and the EU for the treatment of patients with moderate to severe dementia of the Alzheimer's type. In well designed clinical trials, oral memantine, as monotherapy or in addition to a stable dose of acetylcholinesterase inhibitors, was well tolerated during the treatment of mild to severe Alzheimer's disease for up to 52 weeks. Memantine generally modified the progressive symptomatic decline in global status, cognition, function and behaviour exhibited by patients with moderate to severe Alzheimer's disease in four 12- to 28-week trials. In patients with mild to moderate Alzheimer's disease, data from three 24-week trials are equivocal, although meta-analyses indicate beneficial effects on global status and cognition. Memantine is an effective pharmacotherapeutic agent, and currently the only approved option, for the treatment of moderate to severe Alzheimer's disease.

A Systematic Review of the Clinical and Cost-Effectiveness of Memantine in Patients with Moderately Severe to Severe Alzheimer???s Disease

Alzheimer's disease (AD) is the most common form of dementia and is characterised by a worsening of cognition, functional ability, and behaviour and mood. The objective of this study was to review the clinical and cost-effectiveness of memantine for the treatment of patients with moderately severe to severe AD. To achieve this, a systematic search and review of the clinical and cost effectiveness literature for memantine was undertaken. The literature search covered the period from the inception of MEDLINE, Cochrane Library, EMBASE and other electronic databases until July 2004. The search included randomised controlled trials (RCTs) and full economic evaluations that assessed the use of memantine in patients with moderately severe to severe AD. Two published RCTs were included in this review; in one of these trials the participants were already being treated with donepezil. The two RCTs showed benefit for patients receiving memantine compared with placebo on the outcome measures of the Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory modified for severe dementia, the Clinician's Interview-Based Impression of Change Plus Caregiver Input, and the Severe Impairment Battery, and that memantine appeared to be slightly more effective in patients already receiving a stable dose of donepezil. Five cost-effectiveness studies were included in the review. Although these studies reported cost reductions and improved outcomes with memantine, the evaluations were based on a number of assumptions. In conclusion, memantine appears to be beneficial when assessed using functional and global measurements. However, the effect of memantine on cognitive scores and behaviour and mood outcomes is less clear. Cost-effectiveness is dependent upon assumptions surrounding clinical effect and context-specific cost data.