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.

Cost-utility analysis of memantine extended release added to cholinesterase inhibitors compared to cholinesterase inhibitor monotherapy for the treatment of moderate-to-severe dementia of the Alzheimer's type in the US

OBJECTIVE

This study evaluates the cost-effectiveness of memantine extended release (ER) as an add-on therapy to acetylcholinesterase inhibitor (AChEI) [combination therapy] for treatment of patients with moderate-to-severe Alzheimer's disease (AD) from both a healthcare payer and a societal perspective over 3 years when compared to AChEI monotherapy in the US.

METHODS

A phase III trial evaluated the efficacy and safety of memantine ER for treatment of AD patients taking an AChEI. The analysis assessed the long-term costs and health outcomes using an individual patient simulation in which AD progression is modeled in terms of cognition, behavior, and functioning changes. Input parameters are based on patient-level trial data, published literature, and publicly available data sources. Changes in anti-psychotic medication use are incorporated based on a published retrospective cohort study. Costs include drug acquisition and monitoring, total AD-related medical care, and informal care associated with caregiver time. Incremental cost-utility ratio (ICUR), life years, care time for caregiver, time in community and institution, time on anti-psychotics, time by disease severity, and time without severe symptoms are reported. Costs and health outcomes are discounted at 3% per annum.

RESULTS

Considering a societal perspective over 3 years, this analysis shows that memantine ER combined with an AChEI provides better clinical outcomes and lower costs than AChEI monotherapy. Discounted average savings were estimated at $18,355 and $20,947 per patient and quality-adjusted life-years (QALYs) increased by an average of 0.12 and 0.13 from a societal and healthcare payer perspective, respectively. Patients on combination therapy spent an average of 4 months longer living at home and spend less time in moderate-severe and severe stages of the disease.

CONCLUSION

Combination therapy for patients with moderate-to-severe AD is a cost-effective treatment compared to AChEI monotherapy in the US.

Evaluating disease-modifying agents: a simulation framework for Alzheimer's disease

BACKGROUND

Considerable advances have been made in modeling Alzheimer's disease (AD), with a move towards individual-level rather than cohort models and simulations that consider multiple dimensions when evaluating disease severity. However, the possibility that disease-modifying agents (DMAs) may emerge requires an update of existing modeling frameworks.

OBJECTIVES

The aim of this study was to develop a simulation allowing for economic evaluation of DMAs in AD.

METHODS

The model was developed based on a previously published, well-validated, discrete event simulation which measures disease severity on the basis of cognition, behaviour, and function, and captures the interrelated changes in these measures for individuals. The updated model adds one more domain, patient dependence, in addition to cognition, behaviour, and function to better characterize disease severity. Furthermore, the model was modified to have greater flexibility in assessing the impact of various important assumptions, such as the long-term effectiveness of DMAs and their impact on survival, on model outcomes. A validation analysis was performed to examine how well the model predicted change in disease severity among patients not receiving DMA treatment by comparing model results to those observed in two recent phase III clinical trials of bapineuzumab. In addition, various hypothetical scenarios were tested to demonstrate the improved features of the model.

RESULTS

Validation results show that the model closely predicts the mean changes in disease severity over 18 months. Results from different hypothetical scenarios show that the model allows for credible assessment of those major uncertainties surrounding the long-term effectiveness of DMAs, including the potential impact of improved survival with DMA treatment. They also indicate that varying these assumptions could have a major impact on the value of DMAs.

CONCLUSIONS

The updated economic model has good predictive power, but validation against longer-term outcomes is still needed. Our analyses also demonstrate the importance of designing a model with sufficient flexibility such that the model allows for assessment of the impact of key sources of uncertainty on the value of DMAs.

Economic implications of using bendamustine, alemtuzumab, or chlorambucil as a first-line therapy for chronic lymphocytic leukemia in the US: a cost-effectiveness analysis

BACKGROUND

The objective of this analysis was to evaluate the cost-effectiveness of using bendamustine versus alemtuzumab or bendamustine versus chlorambucil as a first-line therapy in patients with Binet stage B or C chronic lymphocytic leukemia (CLL) in the US.

METHODS

A discrete event simulation of the disease course of CLL was developed to evaluate the economic implications of single-agent treatment with bendamustine, alemtuzumab, or chlorambucil, which are indicated for a treatment-naïve patient population with Binet stage B or C CLL. Data from clinical trials were used to create a simulated patient population, risk equations for progression-free survival and survival post disease progression, response rates, and rates of adverse events. Costs from a US health care payer perspective in 2012 US dollars, survival (life years), and quality-adjusted life years (QALYs) were estimated over a patient's lifetime; all were discounted at 3% per year.

RESULTS

Compared with alemtuzumab, bendamustine was considered to be a dominant treatment providing greater benefit (6.10 versus 5.37 life years and 4.02 versus 3.45 QALYs) at lower cost ($78,776 versus $121,441). Compared with chlorambucil, bendamustine was associated with higher costs ($78,776 versus $42,337) but with improved health outcomes (6.10 versus 5.21 life years and 4.02 versus 3.30 QALYs), resulting in incremental cost-effectiveness ratios of $40,971 per life year gained and $50,619 per QALY gained.

CONCLUSION

Bendamustine is expected to provide cost savings and greater health benefit than alemtuzumab in treatment-naïve patients with CLL. Furthermore, it can be considered as a cost-effective treatment providing health benefits at an acceptable cost versus chlorambucil in the US.

Smoking cessation treatment and outcomes patterns simulation: a new framework for evaluating the potential health and economic impact of smoking cessation interventions

BACKGROUND

Most existing models of smoking cessation treatments have considered a single quit attempt when modelling long-term outcomes.

OBJECTIVE

To develop a model to simulate smokers over their lifetimes accounting for multiple quit attempts and relapses which will allow for prediction of the long-term health and economic impact of smoking cessation strategies.

METHODS

A discrete event simulation (DES) that models individuals' life course of smoking behaviours, attempts to quit, and the cumulative impact on health and economic outcomes was developed. Each individual is assigned one of the available strategies used to support each quit attempt; the outcome of each attempt, time to relapses if abstinence is achieved, and time between quit attempts is tracked. Based on each individual's smoking or abstinence patterns, the risk of developing diseases associated with smoking (chronic obstructive pulmonary disease, lung cancer, myocardial infarction and stroke) is determined and the corresponding costs, changes to mortality, and quality of life assigned. Direct costs are assessed from the perspective of a comprehensive US healthcare payer ($US, 2012 values). Quit attempt strategies that can be evaluated in the current simulation include unassisted quit attempts, brief counselling, behavioural modification therapy, nicotine replacement therapy, bupropion, and varenicline, with the selection of strategies and time between quit attempts based on equations derived from survey data. Equations predicting the success of quit attempts as well as the short-term probability of relapse were derived from five varenicline clinical trials.

RESULTS

Concordance between the five trials and predictions from the simulation on abstinence at 12 months was high, indicating that the equations predicting success and relapse in the first year following a quit attempt were reliable. Predictions allowing for only a single quit attempt versus unrestricted attempts demonstrate important differences, with the single quit attempt simulation predicting 19 % more smoking-related diseases and 10 % higher costs associated with smoking-related diseases. Differences are most prominent in predictions of the time that individuals abstain from smoking: 13.2 years on average over a lifetime allowing for multiple quit attempts, versus only 1.2 years with single quit attempts. Differences in abstinence time estimates become substantial only 5 years into the simulation. In the multiple quit attempt simulations, younger individuals survived longer, yet had lower lifetime smoking-related disease and total costs, while the opposite was true for those with high levels of nicotine dependence.

CONCLUSION

By allowing for multiple quit attempts over the course of individuals' lives, the simulation can provide more reliable estimates on the health and economic impact of interventions designed to increase abstinence from smoking. Furthermore, the individual nature of the simulation allows for evaluation of outcomes in populations with different baseline profiles. DES provides a framework for comprehensive and appropriate predictions when applied to smoking cessation over smoker lifetimes.

Improved perioperative blood pressure control leads to reduced hospital costs

BACKGROUND

Perioperative hypertension affects 80% of cardiac surgery patients and is associated with an increased risk of complications.

OBJECTIVE

To determine the relationship between perioperative blood pressure (BP) control and hospital costs for cardiac surgery in the United States (US) and estimate the potential cost reductions associated with effective therapies.

METHODS

The analysis estimated hospitalization costs (2011 US dollars (USD)) for cardiac surgery when BP was controlled with intravenous (IV) antihypertensives. Patient characteristics, hospital length of stay, and clinical event rates during the initial hospitalization and post-discharge 30 days after study drug infusion were based on the ECLIPSE (Evaluation of CLevidipine In the Perioperative Treatment of Hypertension Assessing Safety Events) trials. These clinical trial data were combined with data from the Massachusetts Acute Hospital Case Mix Database 2007 - 2009 (MA Case Mix Database) to estimate total hospitalization costs.

RESULTS

Effective perioperative BP control in patients requiring IV antihypertensives was associated with a 7% decrease in hospital costs compared with less effective BP control. Reductions in total hospital costs associated with clevidipine versus other IV antihypertensives averaged $394 per patient overall. Cost savings with clevidipine exceeded $500 per patient versus sodium nitroprusside and nitroglycerin, but only $22 compared to nicardipine.

CONCLUSION

Improved perioperative BP control may reduce hospital costs. Given the low cost of IV antihypertensives, the total hospital cost reductions may offset any incremental cost increases associated with newer, more effective therapies.

Accounting for the relationship between per diem cost and LOS when estimating hospitalization costs

Background

Hospitalization costs in clinical trials are typically derived by multiplying the length of stay (LOS) by an average per-diem (PD) cost from external sources. This assumes that PD costs are independent of LOS. Resource utilization in early days of the stay is usually more intense, however, and thus, the PD cost for a short hospitalization may be higher than for longer stays. The shape of this relationship is unlikely to be linear, as PD costs would be expected to gradually plateau. This paper describes how to model the relationship between PD cost and LOS using flexible statistical modelling techniques.

Methods

An example based on a clinical study of clevidipine for the treatment of peri-operative hypertension during hospitalizations for cardiac surgery is used to illustrate how inferences about cost-savings associated with good blood pressure (BP) control during the stay can be affected by the approach used to derive hospitalization costs.

Data on the cost and LOS of hospitalizations for coronary artery bypass grafting (CABG) from the Massachusetts Acute Hospital Case Mix Database (the MA Case Mix Database) were analyzed to link LOS to PD cost, factoring in complications that may have occurred during the hospitalization or post-discharge. The shape of the relationship between LOS and PD costs in the MA Case Mix was explored graphically in a regression framework. A series of statistical models including those based on simple logarithmic transformation of LOS to more flexible models using LOcally wEighted Scatterplot Smoothing (LOESS) techniques were considered. A final model was selected, using simplicity and parsimony as guiding principles in addition traditional fit statistics (like Akaike’s Information Criterion, or AIC). This mapping was applied in ECLIPSE to predict an LOS-specific PD cost, and then a total cost of hospitalization. These were then compared for patients who had good vs. poor peri-operative blood-pressure control.

Results

The MA Case Mix dataset included data from over 10,000 patients. Visual inspection of PD vs. LOS revealed a non-linear relationship. A logarithmic model and a series of LOESS and piecewise-linear models with varying connection points were tested. The logarithmic model was ultimately favoured for its fit and simplicity. Using this mapping in the ECLIPSE trials, we found that good peri-operative BP control was associated with a cost savings of $5,366 when costs were derived using the mapping, compared with savings of $7,666 obtained using the traditional approach of calculating the cost.

Conclusions

PD costs vary systematically with LOS, with short stays being associated with high PD costs that drop gradually and level off. The shape of the relationship may differ in other settings. It is important to assess this and model the observed pattern, as this may have an impact on conclusions based on derived hospitalization costs.

Inclusion of compliance and persistence in economic models: past, present and future

Economic models are developed to provide decision makers with information related to the real-world effectiveness of therapeutics, screening and diagnostic regimens. Although compliance with these regimens often has a significant impact on real-world clinical outcomes and costs, compliance and persistence have historically been addressed in a relatively superficial fashion in economic models. In this review, we present a discussion of the current state of economic modelling as it relates to the consideration of compliance and persistence. We discuss the challenges associated with the inclusion of compliance and persistence in economic models and provide an in-depth review of recent modelling literature that considers compliance or persistence, including a brief summary of previous reviews on this topic and a survey of published models from 2005 to 2012. We review the recent literature in detail, providing a therapeutic-area-specific discussion of the approaches and conclusions drawn from the inclusion of compliance or persistence in economic models. In virtually all publications, variation of model parameters related to compliance and persistence was shown to have a significant impact on predictions of economic outcomes. Growing recognition of the importance of compliance and persistence in the context of economic evaluations has led to an increasing number of economic models that consider these factors, as well as the use of more sophisticated modelling techniques such as individual simulations that provide an avenue for more rigorous consideration of compliance and persistence than is possible with more traditional methods. However, we note areas of continuing concern cited by previous reviews, including inconsistent definitions, documentation and tenuous assumptions required to estimate the effect of compliance and persistence. Finally, we discuss potential means to surmount these challenges via more focused efforts to collect compliance and persistence data.

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.

Discrete event simulation: the preferred technique for health economic evaluations?

OBJECTIVES

To argue that discrete event simulation should be preferred to cohort Markov models for economic evaluations in health care.

METHODS

The basis for the modeling techniques is reviewed. For many health-care decisions, existing data are insufficient to fully inform them, necessitating the use of modeling to estimate the consequences that are relevant to decision-makers. These models must reflect what is known about the problem at a level of detail sufficient to inform the questions. Oversimplification will result in estimates that are not only inaccurate, but potentially misleading.

RESULTS

Markov cohort models, though currently popular, have so many limitations and inherent assumptions that they are inadequate to inform most health-care decisions. An event-based individual simulation offers an alternative much better suited to the problem. A properly designed discrete event simulation provides more accurate, relevant estimates without being computationally prohibitive. It does require more data and may be a challenge to convey transparently, but these are necessary trade-offs to provide meaningful and valid results.

CONCLUSION

In our opinion, discrete event simulation should be the preferred technique for health economic evaluations today.

Cost effectiveness of donepezil in the treatment of mild to moderate Alzheimer's disease: a UK evaluation using discrete-event simulation

Recommendations in the UK suggest restricting treatment of Alzheimer's disease with cholinesterase inhibitors, on cost-effectiveness grounds, to patients with moderate cognitive decline. As the economic analyses that informed these recommendations have been the subject of debate, we sought to address the potential limitations of existing models and produce estimates of donepezil treatment cost effectiveness in the UK using the most recent available data and simulation techniques. A discrete-event simulation was developed that predicts progression of Alzheimer's disease through correlated changes in cognition, behavioural disturbance and function. Patient-level data from seven randomized, placebo-controlled donepezil trials and a 7-year follow-up registry provided the basis for modeling longitudinal outcomes. Individuals in the simulation were assigned unique demographic and clinical characteristics and then followed for 10 years, with severity of disease tracked on continuous scales. Patient mix and costs were developed from UK-specific literature. Analyses were run for severity subgroups to evaluate outcomes for sub-populations with disease of mild versus moderate severity from both a healthcare payer and societal perspective. All costs are reported in pound, year 2007 values, and all outcomes are discounted at 3.5% per annum. Over 10 years, treatment of all patients with mild to moderate disease reduces overall direct medical costs by an average of over pound2300 per patient. When unpaid caregiver time is also taken into consideration, savings increase to over pound4700 per patient. Compared with untreated patients, patients receiving donepezil experience a discounted gain in QALYs averaging 0.11, with their caregivers gaining, on average, 0.01 QALYs. For the subset of patients starting treatment with more severe disease, savings are more modest, averaging about pound1600 and pound3750 from healthcare and societal perspectives, respectively. In probabilistic sensitivity analyses, donepezil dominated no treatment between 57% and 62% of replications when only medical costs were considered, and between 74% and 79% of replications when indirect costs were included, with results more favourable for treatment initiation in the mild versus moderate severity stages of the disease. Although the simulation results are not definitive, they suggest that donepezil leads to health benefits and cost savings when used to treat mild to moderately severe Alzheimer's disease in the UK. They also indicate that both benefits and savings may be greatest when treatment is started while patients are still in the mild stages of Alzheimer's disease.

Adult vaccination strategies for the control of pertussis in the United States: an economic evaluation including the dynamic population effects

Background

Prior economic evaluations of adult and adolescent vaccination strategies against pertussis have reached disparate conclusions. Using static approaches only, previous studies failed to analytically include the indirect benefits derived from herd immunity as well as the impact of vaccination on the evolution of disease incidence over time.

Methods

We assessed the impact of different pertussis vaccination strategies using a dynamic compartmental model able to consider pertussis transmission. We then combined the results with economic data to estimate the relative cost-effectiveness of pertussis immunization strategies for adolescents and adults in the US. The analysis compares combinations of programs targeting adolescents, parents of newborns (i.e. cocoon strategy), or adults of various ages.

Results

In the absence of adolescent or adult vaccination, pertussis incidence among adults is predicted to more than double in 20 years. Implementing an adult program in addition to childhood and adolescent vaccination either based on 1) a cocoon strategy and a single booster dose or 2) a decennial routine vaccination would maintain a low level of pertussis incidence in the long run for all age groups (respectively 30 and 20 cases per 100,000 person years). These strategies would also result in significant reductions of pertussis costs (between −77% and −80% including additional vaccination costs). The cocoon strategy complemented by a single booster dose is the most cost-effective one, whereas the decennial adult vaccination is slightly more effective in the long run.

Conclusions

By providing a high level of disease control, the implementation of an adult vaccination program against pertussis appears to be highly cost-effective and often cost-saving.

Invasive meningococcal disease epidemiology and control measures: a framework for evaluation

BACKGROUND

Meningococcal disease can have devastating consequences. As new vaccines emerge, it is necessary to assess their impact on public health. In the absence of long-term real world data, modeling the effects of different vaccination strategies is required. Discrete event simulation provides a flexible platform with which to conduct such evaluations.

METHODS

A discrete event simulation of the epidemiology of invasive meningococcal disease was developed to quantify the potential impact of implementing routine vaccination of adolescents in the United States with a quadrivalent conjugate vaccine protecting against serogroups A, C, Y, and W-135. The impact of vaccination is assessed including both the direct effects on individuals vaccinated and the indirect effects resulting from herd immunity. The simulation integrates a variety of epidemiologic and demographic data, with core information on the incidence of invasive meningococcal disease and outbreak frequency derived from data available through the Centers for Disease Control and Prevention. Simulation of the potential indirect benefits of vaccination resulting from herd immunity draw on data from the United Kingdom, where routine vaccination with a conjugate vaccine has been in place for a number of years. Cases of disease are modeled along with their health consequences, as are the occurrence of disease outbreaks.

RESULTS

When run without a strategy of routine immunization, the simulation accurately predicts the age-specific incidence of invasive meningococcal disease and the site-specific frequency of outbreaks in the Unite States. 2,807 cases are predicted annually, resulting in over 14,000 potential life years lost due to invasive disease. In base case analyses of routine vaccination, life years lost due to infection are reduced by over 45% (to 7,600) when routinely vaccinating adolescents 12 years of age at 70% coverage. Sensitivity analyses indicate that herd immunity plays an important role when this population is targeted for vaccination. While 1,100 cases are avoided annually when herd immunity effects are included, in the absence of any herd immunity, the number of cases avoided with routine vaccination falls to 380 annually. The duration of vaccine protection also strongly influences results.

CONCLUSION

In the absence of appropriate real world data on outcomes associated with large-scale vaccination programs, decisions on optimal immunization strategies can be aided by discrete events simulations such as the one described here. Given the importance of herd immunity on outcomes associated with routine vaccination, published estimates of the economic efficiency of routine vaccination with a quadrivalent conjugate vaccine in the United States may have considerably underestimated the benefits associated with a policy of routine immunization of adolescents.

NICE cost-effectiveness appraisal of cholinesterase inhibitors: was the right question posed? Were the best tools used?

The National Institute for Health and Clinical Excellence (NICE) recently issued updated guidance on the use of cholinesterase inhibitors in the treatment of Alzheimer's disease. NICE initially recommended that cholinesterase inhibitors no longer be used, but final guidance restricted treatment to patients with disease of a moderately severe stage. This decision was based largely on results from a heavily criticised economic evaluation that used an adaptation of the Assessment of Health Economics in Alzheimer's Disease (AHEAD) model. As the developers of the AHEAD model, we examined the appropriateness of NICE's economic analyses and presentation of results. We attempted to replicate NICE's results by modifying the original AHEAD model. Sensitivity analyses were then run using the modified AHEAD model to evaluate the extent of uncertainty in predictions. The AHEAD(NICE) analyses resulted in an incremental cost-effectiveness ratio for galantamine of 82,000 pound per QALY gained (year 2003 values) from the perspective of the UK NHS and Personal Social Services. This was later revised to 46,000 pound per QALY, compared with < 9000 pound per discounted QALY gained (year 2001 values) in the original AHEAD model. Using our modified AHEAD with effectiveness estimates matching those of AHEAD(NICE), we show that NICE's choice and presentation of sensitivity analyses obscured the instability of their estimates. In the final NICE evaluation, the recommendation to delay treatment with cholinesterase inhibitors until patients have moderately severe disease was based on critical assumptions in the economic analyses that had little evidence to support them. The case of NICE's guidance on cholinesterase inhibitors highlights the importance of transparent and valid economic evaluations and the dangers of using inappropriate modelling technologies, basing analyses on a limited subset of the available data, and insufficiently reflecting the uncertainty in estimates that are intended to inform decision makers.

Managing meningococcal disease in the United States: Hospital case characteristics and costs by age

OBJECTIVE

Meningococcal disease occurs worldwide. Approximately 1400 to 2800 cases are reported in the United States annually. The goal of this analysis was to examine hospitalized cases of meningitis and meningococcemia to identify case characteristics, resource use, and inpatient care costs.

METHODS

International Classification of Diseases-9th Revision-Clinical Modification diagnosis codes 036.0-036.9 were used to identify cases from roughly 1000 hospitals in four all payer state discharge databases. Multiyear data (1999-2001) were examined to identify demographics, admission month, health service utilization, and hospital costs by age group: infant (<1 years), children (1-10 years), adolescent (11-17 years), young adult (18-22 years), adults (23-49 years), and adults (> or =50 years). Cost estimates include accommodations, ancillary and physician services, reported in 2003 US dollars.

RESULTS

Of 1654 cases of meningococcal disease identified, meningococcemia was coded for 51%. Adults accounted for 33% of the cases. The highest rate of admissions occurred from January through March and 62% were admitted via the Emergency Department. Inpatient case fatality rate was 6.4%; 71% of those who died had meningococcemia. The mean length of stay was 9 days. Of survivors, 91% were discharged home (1% with intravenous medications and 11% with other home health-care services) while 7% required further subacute inpatient care. The average cost per hospitalization was estimated at 23,294 dollars per patient. Infants had the lowest average cost per stay (16,793 dollars) and adolescents had the highest (28,202 dollars).

CONCLUSIONS

The presence of meningococcemia results in a greater death rate, longer length of stay, and increased care costs. Meningococcal disease has substantial economic, as well as profound clinical consequences for patients of all ages.

Assessing the health and economic impact of galantamine treatment in patients with Alzheimer's disease in the health care systems of different countries

INTRODUCTION

Cholinesterase inhibitors have been shown to improve cognitive function and improve or maintain global function.

OBJECTIVE

To estimate the long-term economic impact of treating patients with Alzheimer's disease with galantamine in seven healthcare systems: Australia, Canada, Finland, New Zealand, Sweden, the Netherlands and the UK.

METHODS

The time until patients require full-time care (FTC), defined as the consistent requirement for a significant amount of care giving and supervision each day, and the associated costs were evaluated using the 'Assessment of Health Economics in Alzheimer's Disease (AHEAD)' model. Efficacy data were obtained from three clinical trials comparing galantamine with placebo and local cost and resource use data were determined for each country. Forecast costs reported in Euros (2001 value), were made for up to 10 years in each healthcare system. All costs were determined from a perspective somewhat broader than that of a comprehensive payer, including social services. Both benefits and costs were discounted at 3%.

RESULTS

Galantamine (16 mg/day) is predicted to delay the need for FTC by 6.8%, thus the cumulative cost of care over 10 years is expected to be reduced, and this offsets much or all of the cost of galantamine. Approximately five patients need to be treated to avoid 1 year of FTC. In each healthcare system, FTC was estimated to account for 61-92% of the cost. Savings were estimated for most of the countries. For those countries with an expected expense, there were reasonable costs per FTC month avoided (euro553, discounted) and costs per quality-adjusted life year gained (euro25,000).

CONCLUSION

In addition to the clinical benefits associated with galantamine treatment, the savings predicted from delaying FTC may offset the treatment costs.

Economic burden of pertussis and the impact of immunization

Although routine use of vaccines has diminished the incidence of pertussis disease, it has not eliminated the pathogen. Epidemiologic data confirm that pertussis remains a significant health problem in all age groups. Disease burden is highest in infants, in whom pertussis disease frequently leads to severe complications and mortality, although it is also a significant health burden in adolescents and adults, in whom the reported incidence of pertussis is increasing. The Global Pertussis Initiative reviewed the literature to find data that express the economic impact of this health burden and to review economic evaluations of pertussis immunization. Although only limited data on the direct and indirect costs of pertussis are available, they suggest that it poses a significant economic burden and indicate that the direct medical costs of pertussis depend on the rate of hospitalization and the severity of complications, and are highest in infants. The indirect costs of pertussis also appear to be considerable, particularly among adults, in whom the disease reduces work productivity, because of either personal illness or child care responsibilities. Several health economic models on the cost effectiveness of childhood immunization strategies have been published, and although constrained by missing data, have generally found childhood immunization strategies to be cost-effective. Economic analyses of adolescent and adult immunization strategies have also been conducted, but the findings of these studies have been inconsistent. The most recent evaluations, using much higher estimates of incidence than reported previously, suggest that immunization of adolescents and specific adult subgroups may be cost-effective. The literature review confirmed that the economic burden of pertussis is substantial, but there are gaps in existing information. In the short term, further economic analyses are required, particularly of adolescent and adult immunization. More importantly, collection of primary epidemiologic and economic data should be undertaken in parallel. Despite the existing gaps in data, further research using the most current data should facilitate decisions on new vaccination strategies by describing conditions for favorable results and quantifying the margin of uncertainty.

Pertussis immunization of adolescents in the United States: an economic evaluation

The incidence of reported pertussis has increased during the past decade and poses a growing health and economic burden in developed countries, despite high rates of primary vaccination. Administration of a booster dose of acellular pertussis vaccine to adolescents may help reduce this burden, not only by reducing infections in vaccinated individuals but also by reducing transmission of Bordetella pertussis to other individuals, particularly infants. An epidemiologic model was created to assess the health and economic impact of implementing a program of routine acellular pertussis immunization in adolescents 11-18 years of age in the United States, considering both the reduction in cases in those vaccinated and among the unvaccinated population (due to herd immunity). Inputs for the base case were defined according to information derived from published literature and were supplemented by estimates provided by members of the Global Pertussis Initiative. Both direct and indirect costs were included (in 2002 US dollars) using U.S. data. Outcomes were evaluated over the lifetime of a cohort of potential adolescent vaccine candidates. Because of uncertainty in many of the inputs, extensive sensitivity analyses were conducted. With 80% vaccination coverage of adolescents and a 20% reduction of other cases because of herd immunity, >68,000 cases and 41 pertussis-related deaths would be avoided in the subsequent 10 years by routine administration of acellular pertussis boosters to a single cohort of adolescents in the United States. This strategy would be cost-effective, incurring from 6000 US dollars to 22,000 US dollars per life-year gained. The level of herd immunity attained and the true incidence of pertussis are critical determinants of cost effectiveness, as is the duration of immunity resulting from immunization. The cost of immunization and the discount rate also play a role. Although there is considerable uncertainty surrounding key inputs, the results indicate that the conditions required for adolescent immunization to be economically warranted are realistic.

Pharmacological management of overactive bladder : a systematic and critical review of published economic evaluations

Overactive bladder is a common condition, with recent findings estimating the prevalence in adults at about 15%. Symptoms, including urinary urgency, high voiding frequency and urge incontinence, have been shown to decrease patients' quality of life. Given its high prevalence, the economic burden of overactive bladder is also substantial, with a recent estimate placing the annual cost in the US at 9.1 billion US dollars (year 2000 values). The objective of this review is to provide a critical appraisal of published economic evaluations of pharmacological and non-pharmacological treatments for overactive bladder. Published economic evaluations of treatments for overactive bladder have focused entirely on pharmacological treatments -- mainly on the two most commonly used drugs, oxybutynin and tolterodine, each of which is available in immediate- and extended-release formulations. Ten economic evaluations (more than half are cost-effectiveness studies) have been published. Modelling with decision trees or Markov models has been the predominant method. Evaluations comparing drug therapy with no treatment have concluded that drug therapy is cost effective. Analyses comparing the formulations of oxybutynin and tolterodine have produced highly inconsistent results, largely due to the sources of data employed for effectiveness and treatment discontinuation rates. There are no evaluations of drugs relative to non-pharmacological treatment, and there are other significant gaps in the economic evaluations of treatment to date. These include gaps resulting from a lack of reliable data on the performance of these drugs in real-world settings, particularly data on long-term persistence with treatment. A more definitive pharmacoeconomic comparison of oxybutynin and tolterodine formulations, incorporating all available clinical data, and other treatment options would help direct treatment.

Economic evaluation of therapeutic interventions to prevent Type 2 diabetes in Canada

AIMS

To compare the health and economic outcomes of using acarbose, an intensive lifestyle modification programme, metformin or no intervention to prevent progression to diabetes in Canadian individuals with impaired glucose tolerance (IGT).

METHODS

A model was developed to simulate the course of individuals with IGT under each treatment strategy. Patients remain in the IGT state or transition from IGT to diabetes, to normal glucose tolerance (NGT) or to death. Effectiveness and resource use data were derived from published intervention trials. A comprehensive health-care payer perspective incorporating all major direct costs, reported in 2000 Canadian dollars, was adopted.

RESULTS

Over a decade, 70 of the 1000 untreated patients are expected to die and 542 develop diabetes. Intensive lifestyle modification is estimated to prevent 117 cases of diabetes, while metformin would prevent 52 and acarbose 74 cases. The proportion of those who return to NGT also increases with any treatment. While lifestyle modification is more effective, it can increase overall costs depending on how it is implemented, whereas acarbose and metformin reduce costs by nearly $1000 per patient. Lifestyle modification was cost effective, varying from CAD $10 000/LYG vs. acarbose. Acarbose costs somewhat more than metformin, but is more effective: CAD $1798/LYG.

CONCLUSION

The results of this model suggest that the treatment of IGT in Canada is a cost-effective way to prevent diabetes and may generate savings. While pharmacological treatments tended to be less costly, intensive lifestyle modification, if maintained, led to the greatest health benefits at reasonable incremental costs.

Canadian economic comparison of extended-release oxybutynin and immediate-release tolterodine in the treatment of overactive bladder

BACKGROUND

Overactive bladder (OAB) is a condition characterized by urgency, increased frequency of micturition, or urge incontinence. It affects a considerable segment of the population, particularly with increasing age. Pharmacotherapy is one of the most common approaches to the treatment of OAB.

OBJECTIVE

This article describes the development and results of a model comparing health-economic outcomes for the new extended-release (XL) formulation of oxybutynin and immediate-release (IR) tolterodine in a population of community-dwelling Canadian adults with OAB.

METHODS

A Markov model was developed to compare health-economic outcomes over the course of 1 year. Effectiveness and treatment-persistence data were derived from the OBJECT (Overactive Bladder: Judging Effective Control and Treatment) trial, a 3-month comparison of oxybutynin XL 10 mg and tolterodine IR 4 mg, and were used, together with data from the literature (identified through a MEDLINE search of articles published between 1990 and 2003), to project outcomes beyond the trial period. Severity-specific cost profiles for incontinence were developed. In the principal analyses, cost items were limited to drug therapy, physician visits, use of pads or other protection, and laundry costs. Costs are reported in 2002 Canadian dollars.

RESULTS

Costs after 1 year were estimated to be an average of $32 less per patient for oxybutynin XL compared with tolterodine IR, and 3.1 additional patients in every 100 who received oxybutynin XL were expected to attain complete continence compared with those who received tolterodine. During the course of 1 year, patients receiving oxybutynin XL were expected to have a mean 16.5 additional incontinence-free days compared with those receiving tolterodine IR. The results were sensitive to relative drug prices. In the other sensitivity analyses, however, oxybutyrin XL maintained its advantage over a wide range of inputs.

CONCLUSION

The results of these analyses suggest that when priced equivalently, oxybutynin XL would reduce costs and provide better results than tolterodine IR over 1 year of treatment.

Assessing the economics of vaccination forNeisseria meningitidisin industrialized nations: A review and recommendations for further research

Objectives:To review the existing health economic literature on meningococcal disease vaccination.

Methods:A Medline search for economic evaluations of vaccination programs for meningococcal disease in developed countries was conducted. All identified studies were reviewed.

Results:Nine published studies were identified examining either mass vaccination during outbreaks or routine vaccination. Although net expenses were estimated in almost all studies, the resulting cost-effectiveness ratios varied widely. Vaccination of college-age students was found to be potentially cost-effective in Australia but not in the United States. With one exception, routine vaccination of children and adolescents in Europe was predicted to be cost-effective. Many simplifying assumptions were made, and important elements were often left out, in particular the potential for reduced transmission of disease.

Conclusions:The methods used and the vaccination strategies vary widely, and results do not provide strong grounds for making conclusions as to whether vaccination is cost-effective. Furthermore, in all instances, transmission of disease, changes in population carriage rates, and outbreaks are either ignored, dealt with using very broad simplifying assumptions, or are not necessarily generalizable to other settings. The analyses provide some insight into the potential cost-effectiveness of vaccination, but more importantly, they highlight areas requiring further study. Economic evaluations based on observed outcomes from recently implemented strategies would be helpful, as would more sophisticated health economic models. The choice of vaccination strategies cannot be based on the results of existing economic analyses.

Oxybutynin Extended Release and Tolterodine Immediate Release

OBJECTIVE

To evaluate the cost-effectiveness of a new extended-release (XL) formulation of oxybutynin relative to tolterodine immediate release (IR), currently the most prescribed treatment for overactive bladder in the UK.

METHODS

A state-transition model was developed to compare outcomes over 1 year. Effectiveness and treatment persistence data were derived from the OBJECT (Overactive Bladder: Judging Effective Control and Treatment) study, a 3-month clinical trial comparing oxybutynin XL 10 mg/day with tolterodine IR 4 mg/day. The daily costs of oxybutynin XL and tolterodine IR were pound0.82 and pound1.04, respectively. These data and information from the literature were used to project outcomes beyond the trial time. Severity-specific incontinence cost profiles were developed for the UK (2002 costings).

RESULTS

After 1 year, 3.1 more patients per 100 treated attained complete continence with oxybutynin XL compared with tolterodine IR, and 5.6% more had less than seven incontinent episodes per week. Over 1 year, patients receiving oxybutynin XL had almost 17 additional incontinence-free days and 95 fewer incontinent episodes. Estimated costs were pound86 lower per patient with oxybutynin XL. If drugs are priced equally, savings decrease to pound21 per patient. Oxybutynin XL maintains its advantage over wide ranges of inputs, and outcomes are similar if analyses are limited to 3 months.

CONCLUSION

Base-case analyses suggest that oxybutynin XL provides better effectiveness than tolterodine IR and reduces costs. Results indicate that oxybutynin XL is the dominant therapeutic option under a wide range of alternative inputs and assumptions.

Rational choice of cholinesterase inhibitor for the treatment of Alzheimer's disease in Canada: a comparative economic analysis

BACKGROUND

Cholinesterase inhibitors, such as galantamine, donepezil and rivastigmine are approved for symptomatic treatment of Alzheimer's Disease (AD) in Canada. In making choices amongst these drugs, one should consider their clinical merits and their economic implications.

METHODS

Each drug's short-term efficacy was estimated based on independent Cochrane reviews of the clinical trials. Long-term clinical and economic outcomes were estimated using the Assessment of Health Economics in Alzheimer's Disease (AHEAD) model.

RESULTS

While all treatments reduced the need for full-time care, only galantamine and donepezil 10 mg reduced the overall management costs of AD patients. The somewhat greater cognitive effect provided over six months by galantamine leads to the longest estimated delay before full-time care is required and, consequently to lower overall costs, with savings estimated at between 323 dollars and 4,246 dollars.

CONCLUSION

Although there is uncertainty in estimated results, the best information currently available suggests that the first choice for treatment of AD should be galantamine. These results should be interpreted with caution, however, as results are not based on direct comparisons among the drugs and the differences emerging from meta-analyses of the trials are relatively small.

Assessment of health economics in Alzheimer's disease (AHEAD): treatment with galantamine in the UK

OBJECTIVE

To assess the long-term health and economic impact of treating mild to moderate Alzheimer's disease (AD) with galantamine (16 mg or 24 mg per day) compared to no cholinesterase therapy in the UK.

METHODS

The long-term costs and outcomes were assessed using a model developed from longitudinal data on a cohort of AD patients. The model predicts the time until patients require full-time care, defined as the consistent requirement for a significant amount of care and supervision each day. Efficacy data were obtained from three clinical trials comparing galantamine with placebo, forecasts were made for ten years. Costs were determined in 2001 British pounds and discounted at 6% per annum, while outcomes such as time to full-time care were discounted at 1.5%.

RESULTS

Without pharmacological treatment, patients are expected to incur costs of 28,134 British pounds over ten years, 70% of costs accrue from providing full-time care. Galantamine (16 mg per day) is predicted to reduce the duration of the full-time care state by 12%; approximately five patients need to be treated to avoid one year of full-time care. The ten-year incremental costs per month of full-time care avoided average pound 192 British pounds per patient and 8,693 British pounds per QALY. Savings (1380 British pounds) are predicted for patients who continue treatment beyond six months and whose cognitive function is maintained or improved. Comparable results were estimated for the 24 mg dose.

CONCLUSION

In addition to the clinical benefits associated with galantamine treatment, the savings predicted from delaying when full-time care is needed may offset the treatment costs.

Economic evaluation of galantamine in the treatment of mild to moderate Alzheimer's disease in the United States

BACKGROUND

Alzheimer's disease (AD) is estimated to affect up to 11% of those aged > or =65 years in the United States, and the number of patients with AD is predicted to increase over the next few decades as the population ages. The substantial social and economic burden associated with AD is well established, with the cost of management increasing as the disease progresses.

OBJECTIVE

The aim of this study was to evaluate the economic impact of galantamine 16 and 24 mg/d relative to no pharmacologic treatment in the management of mild to moderate AD in the United States based on the concept of need for full-time care (FTC).

METHODS

Calculations were made using the Assessment of Health Economics in Alzheimer's Disease model, which applies predictive equations to estimate the need for FTC and the associated costs. The predictive equations were developed from longitudinal data on patients with AD. Inputs to the equations were derived by analyzing the data from 2 randomized, placebo-controlled, galantamine clinical trials. Resource use (from a payer perspective) was estimated from US clinical trial data, and costs were estimated from several US databases. Analyses were carried out over 10 years, and costs and benefits were discounted at 3%.

RESULTS

In the base case, 3.9 to 4.6 patients need to start treatment with galantamine to avoid 1 year of FTC, depending on dose. Treated patients spent 7% to 8% more time pre-FTC and 12% to 14% less time requiring FTC, resulting in savings of 2408 to 3601 US dollars. Time horizons below 3 years, very high discontinuation rates, or increased survival with galantamine reversed the savings. Conversely, limiting treatment to responders delayed FTC by 6 to 7 months, with savings of approximately 9097 to 11,578 US dollars.

CONCLUSIONS

These results suggest that use of galantamine in patients with AD in the United States could reduce the use of costly resources such as formal home care and nursing homes, leading to cost savings over time.

Economic analysis of galantamine, a cholinesterase inhibitor, in the treatment of patients with mild to moderate Alzheimer's disease in the Netherlands

BACKGROUND

The economic impact of dementia on the Dutch health and social services is substantial.

OBJECTIVE

To predict the long-term economic impact of galantamine, a cholinesterase inhibitor, in the treatment of Dutch patients with mild to moderate Alzheimer's disease.

METHOD

A pharmacoeconomic model was used to predict long-term outcomes. It has two components: an initial module based on clinical trials of galantamine and a subsequent module that predicts when a patient will deteriorate to a level where full time care (FTC) is needed. The analyses take a broad perspective that includes all formal (paid) care, not just those covered by the Dutch health care system. Direct cost estimates were based on resource use profiles of patients with Alzheimer's disease in the Netherlands. Key inputs were tested in sensitivity analyses.

RESULTS

After 10.5 years all patients are predicted to require FTC. For every hundred patients starting treatment on galantamine at the mild to moderate stage, it is predicted that 18 person-years of FTC will be avoided (14.4 discounted) and about 5 quality-adjusted years of life will be gained (3.9 discounted). Net savings for those starting treatment with galantamine are estimated at NLG 3,050 (1,676 UDS). The cost of galantamine accounts for only about 5.0% of the total cost of care for treated Alzheimer's patients. The direction of these results remained unchanged when input values and assumptions were tested in sensitivity analyses.

CONCLUSIONS

The cholinesterase inhibitor galantamine is expected to bring savings in the direct cost of caring for patients with Alzheimer's disease in the Netherlands.

To what degree does cognitive impairment in Alzheimer's disease predict dependence of patients on caregivers?

BACKGROUND

Patients with Alzheimer's disease experience a progressive loss of cognitive function, and the ability to independently perform activities of daily life. Sometimes a dependent stage is reached quite early in the disease, when caregivers decide that the patients can no longer be left alone safely. This is an important aspect of Alzheimer's for patients, their families, and also health care providers. Understanding the relationship between a patient's current cognitive status and their need for care may assist clinicians when recommending an appropriate management plan. In this study, we investigated the relationship of cognitive function to dependence on caregivers before the patients reach a severe stage of the disease.

METHODS

Data were obtained on 1,289 patients with mild-to-moderate Alzheimer's disease studied in two randomised clinical trials of galantamine (ReminylcircledR;). Cognition was assessed using the cognitive part of the Alzheimer's Disease Assessment Scale (ADAS-cog) and Mini-Mental State Examination (MMSE). Patients were considered dependent if they required >12 hours of supervision each day or had high care needs. The Disability Assessment for Dementia (DAD) scale was also used as a measure of dependence. Disability was predicted directly using MMSE and ADAS-cog and compared to predictions from converted scores.

RESULTS

The odds ratio of dependence was significantly higher amongst the patients with worse cognitive impairment, adjusting for age, gender and antipsychotic medication use. For example, a 4-point difference in ADAS-cog score was associated with an increase of 17% (95% CI 11-23) in the adjusted odds for >12 hours of supervision, and of 35% (95% CI 28-43) for dependence. Disability predicted directly using actual ADAS-cog and scores converted from MMSE values had close agreement using the models developed.

CONCLUSION

In patients with mild-to-moderate Alzheimer's disease, even relatively small degrees of poorer cognitive function increased the risk of losing the ability to live independently.

Instituting a routine varicella vaccination program in Canada: an economic evaluation

BACKGROUND

After licensing of a varicella vaccine in Canada in 1998, Health Canada commissioned a study to evaluate options for a vaccination program. The evaluation of a program of vaccination of 12-month-old children, with and without a catch-up program for susceptible 12-year-olds, is presented here.

METHODS

An economic model was developed simulating the expected experience, with and without vaccination, of cohorts of children susceptible to varicella. The cohorts were simulated for 70 years, and infection and complication rates were calculated along with the attendant costs, with an assumed vaccine cost of $60.

RESULTS

With an 85% coverage rate vaccination is expected to reduce the number of chickenpox cases by approximately two-thirds and varicella-related complications by up to 75%. The overall costs of varicella are expected to drop by >$4 million (1998 Canadian dollars) per 100,000 eligible vaccinees, but costs to the health care system are expected to increase by >$2 million. From the health care system perspective, vaccination would cost approximately $42 per discounted case avoided.

INTERPRETATION

Routine varicella vaccination would likely substantially reduce the overall costs of managing chickenpox but would result in an increase in health care expenditures. These findings are consistent with evaluations in other countries.

Pharmacoeconomic evidence and considerations for triptan treatment of migraine

The 5-hydroxytriptamine (5-HT)(1B/1D) agonists (i.e., the triptans) are highly effective in migraine but their high cost relative to other treatments necessitates careful analysis of their cost-effectiveness. The majority of pharmacoeconomic evaluations, nearly all of which deal with sumatriptan, indicate that from the societal perspective triptans are dominant: health outcomes are improved while the overall cost of migraine is reduced. However, the results are more ambiguous from the perspective of the health care payer: reductions in non-drug medical costs are unlikely to offset fully the high drug cost. Thus far, few analyses have explicitly included quality of life (QOL) in their analyses and pharmacoeconomic analyses comparing the different triptans are scant. More research is required in these areas.

Assessment of Health Economics in Alzheimer's Disease (AHEAD): treatment with galantamine in Sweden

BACKGROUND

Like other developed countries with aging populations, Sweden is expecting large increases in the prevalence of Alzheimer's disease and corresponding escalations in the cost of care for patients with this disease. Galantamine, a new acetylcholinesterase inhibitor and nicotinic modulator, has proved effective in managing patients with Alzheimer's disease in clinical trials.

OBJECTIVE

To estimate the long-term health and economic impact of galantamine from the perspective of the public health payer in Sweden.

DESIGN AND SETTING

The Assessment of Health Economics in Alzheimer's Disease (AHEAD) model compares galantamine treatment with no pharmacologic treatment. It consists of a module based on trial data followed by a projection module that uses the trial results to predict the time until patients require full-time care (FTC) or until their death. Forecasts were made for up to 10 years. The model was customised to Sweden by using Swedish resource use profiles obtained from the literature.

RESULTS

Galantamine is predicted to reduce the time patients require FTC by almost 10%. Approximately 5.6 patients with mild-to-moderate disease would need to be treated to avoid one year of FTC. This would result in savings averaging 27 436 Swedish kronas (SEK) [3131 euros (EUR)] per patient over 10 years (1998 values). To avoid one year of FTC, 3.9 patients with moderate disease would need to be treated, with savings averaging SEK49 019 (EUR 5594) per patient over 10.5 years. Sensitivity analyses of key parameters, such as proportion of patients needing FTC treated in the community, cost of care in an institution, cost of FTC care in the community, the price of galantamine, and the discount rate, found savings with galantamine would occur under most circumstances.

CONCLUSION

Galantamine can increase the time before patients require FTC, and may also lead to savings as treatment costs are offset by reductions in other healthcare expenditures and the costs associated with FTC.

Cost effectiveness of tinzaparin sodium versus unfractionated heparin in the treatment of proximal deep vein thrombosis

OBJECTIVE

To evaluate economic and health implications of tinzaparin sodium, a once a day low-molecular-weight heparin (LMWH), versus unfractionated heparin (UFH) in the treatment of acute deep vein thrombosis (DVT) from a US healthcare payer perspective.

STUDY DESIGN

An economic model, composed of two submodules, was created: A short-term module based on clinical trial data covering the first 3 months and a long-term module that projects trial results based on published data for up to 50 years.

METHODS

Clinical trial results were combined with data from long-term follow-up studies of DVT in a model that estimates the health and economic consequences of treatment. Both short- and long-term costs with tinzaparin sodium were compared with UFH, as were health outcomes and quality-adjusted life-years (QALYs).

RESULTS

Patients treated with tinzaparin sodium are estimated to live a mean of 0.9 years longer on average (0.6 discounted), resulting in an increase of 0.8 QALYs (0.5 discounted). At the same time, lifetime savings are US dollars 621 per patient (1999 values), even when all patients receiving tinzapirin sodium are treated as inpatients. Early discharge of patients receiving tinzaparin sodium, or outpatient treatment, would save between US dollars 3000 and US dollars 5000 per patient.

CONCLUSION

Tinzaparin sodium leads to better health outcomes and substantial economic savings compared with UFH treatment when all management costs are considered.

Assessment of health economics in Alzheimer's disease (AHEAD): galantamine treatment in Canada

BACKGROUND

Given the high costs of caring for patients with AD in Canada, it is important to evaluate the costs of new therapies that halt or delay the advancement of AD, relative to the savings associated with delaying disease progression.

METHODS

The Assessment of Health Economics in Alzheimer's Disease (AHEAD) model, which uses algorithms to predict the time until patients with AD require full-time care (FTC), was adapted to Canada to compare treatment with galantamine versus no pharmacologic treatment. Data from two clinical trials provided inputs into the algorithms, and forecasts were made for up to 10 years. Drug and health care costs were evaluated according to the stage of disease based on Quebec unit costs along with follow-up data from the Canadian Study of Health and Aging.

RESULTS

Galantamine is predicted to reduce the duration of FTC by almost 10%. Approximately 5.6 patients with mild to moderate disease must be placed on treatment to avoid one year of FTC, resulting in savings averaging $788 CAD ($528 USD) per patient. For patients with moderate disease, 3.9 patients must be placed on treatment to avoid one year of FTC, with savings predicted at $3718 CAD ($2533 USD) per patient.

CONCLUSION

Galantamine cannot only potentially increase the time before patients require FTC, but may also lead to overall savings because treatment costs are offset by reductions in other health care expenditures.

Assessment of health economics in Alzheimer's disease (AHEAD) based on need for full-time care

OBJECTIVE

To develop a framework for estimating the long-term health and economic consequences of AD based on patient characteristics at a given point in time.

METHODS

A pharmacoeconomic model (Assessment of Health Economics in Alzheimer's Disease, AHEAD) was developed based on equations that relate the probability of needing full-time care (FTC) over time to patient characteristics summarized in index scores. These equations were developed from published data on interquartile times until FTC is needed and until death, using nonlinear regressions of the resulting index-specific hazards. These equations were then incorporated into a hidden Markov framework that allows for calculation of expected time to FTC and to death, as well as of the economic consequences of disease progression. There are three major states in the model: not requiring FTC ("pre-FTC"), requiring FTC, and death.

RESULTS

Outcomes for five sample patients are derived to illustrate application of the AHEAD model. The impact of altering disease markers in these patients is also considered.

CONCLUSION

The need for a generally applicable tool to forecast long-term outcomes based on relatively short-term data is becoming increasingly acute with the advent of new therapies for AD. The AHEAD model provides a relatively simple framework for the prediction of time to FTC requirement based on short-term observed data such as those from clinical trials. Although subject to the uncertainties inherent in modeling, the model nevertheless provides a standard estimation technique that may facilitate comparisons between existing and emerging therapies.

Treatment of migraine in Canada with naratriptan: a cost-effectiveness analysis

OBJECTIVE

To evaluate the cost-effectiveness of naratriptan for the treatment of migraine in Canada.

BACKGROUND

The substantial disability brought on by migraine, coupled with the high prevalence of this disorder, leads to substantial costs. Naratriptan is a newly developed triptan shown to be effective in the treatment of migraine.

METHODS

Monte Carlo modeling techniques were used to simulate the experience of Canadian migraineurs over the course of 1 year. Data from a multinational study comparing oral naratriptan 2.5 mg to customary therapies were used in the cost-effectiveness analysis.

RESULTS

Naratriptan leads to an annual reduction in symptom duration of 225 hours compared to customary therapy not including other triptans. Reductions in lost productivity yield savings of Can $390 (1998 Canadian dollars) relative to customary therapy, which exceed the increase in drug costs resulting in overall savings of Can $109 per year.

CONCLUSIONS

The use of naratriptan in the treatment of migraine is an economically attractive option, leading to savings in overall costs. Increases in drug costs seem acceptable in light of reductions in symptom duration.

Diabetes in Canada: direct medical costs of major macrovascular complications

OBJECTIVES

To estimate direct medical costs of managing major macrovascular complications in diabetic patients.

METHODS

Costs were estimated for acute myocardial infarction (AMI) and ischemic stroke by applying unit costs to typical resource use profiles. Data were obtained from many Canadian sources, including the Ontario Case Cost Project, provincial physician and laboratory fee schedules, provincial formularies, government reports, and peer-reviewed literature. For each complication, the event costs per patient are those associated with resource use specific to the acute episode and any subsequent care occurring in the first year. State costs are the annual costs per patient of continued management. All costs are expressed in 1996 Canadian dollars.

RESULTS

Acute hospital care accounts for approximately half of the first year management costs ($15,125) of AMI. Given the greater need for postacute care, acute hospital care has less impact (28%) on event costs for stroke ($31,076). The state costs for AMI and stroke are $1544 and $8141 per patient, respectively.

CONCLUSIONS

Macrovascular complications of diabetes potentially represent a substantial burden to Canada's health care system. As new therapies emerge that may reduce the incidence of some diabetic complications, decision makers will need information to make critical decisions regarding how to spend limited health care dollars. Published literature lacks Canadian-specific cost estimates that may be readily translated into patient-level cost inputs for an economic model. This paper provides two key pieces of the many needed to understand the scope of the economic burden of diabetes and its complications for Canada.

Sumatriptan: economic evidence for its use in the treatment of migraine, the Canadian comparative economic analysis

The objective of this study was to evaluate economic and health effects of sumatriptan relative to customary therapy in Canada. The relationship between treatment and functionality was established based on analysis of existing data from a multinational study. A Monte Carlo model was developed to simulate 1 year for each of customary therapy and six sumatriptan formulations. Costs are expressed in 1998 Canadian dollars. Sumatriptan is expected to reduce the time spent with migraine symptoms and resulting time lost. Under customary therapy, the annual cost of lost time is estimated at pound908 ($1973). With sumatriptan, these costs ranged from pound406 ($882) with subcutaneous sumatriptan to pound577 ($1254) with nasal sumatriptan 10 mg, saving pound331-502 ($719-1091) in the annual cost of time lost. All these benefits are expected to be obtained at an additional drug cost ranging from pound869 ($1889) for subcutaneous sumatriptan to pound278 ($605) for sumatriptan suppository. The cost of sumatriptan treatment is significantly offset by a substantial reduction of costs associated with time lost due to migraine symptoms.

The migraine ACE model: evaluating the impact on time lost and medical resource Use

OBJECTIVE

To describe the Migraine Adaptive Cost-Effectiveness Model in the context of an analysis of a simulated population of Canadian patients with migraine.

BACKGROUND

The high prevalence of migraine and its substantial impact on patients' ability to function normally present a significant economic burden to society. In light of the recent availability of improved pharmaceutical treatments, a model was developed to assess their economic impact.

METHODS

The Migraine Adaptive Cost-Effectiveness Model incorporates the costs of time lost from both work and nonwork activities, as well as medical resource and medication use. Using Monte Carlo techniques, the model simulates the experience of a population of patients with migraine over the course of 1 year. As an example, analyses of a Canadian population were carried out using data from a multinational trial, surveys, national statistics, and the available literature.

RESULTS

Using customary therapy, mean productivity losses (amounting to 84 hours of paid work time, 48 hours of unpaid work time, and 113 hours of leisure time lost) were estimated to cost $1949 (in 1997 Canadian dollars) per patient, with medical expenditures adding an average of $280 to the cost of illness.

CONCLUSIONS

With customary treatment patterns, the costs of migraine associated with reduced functional capacity are substantial. The migraine model represents a flexible tool for the economic evaluation of different migraine treatments in various populations.