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Ne perds pas la carte - Soutien à la formation et la recherche sur la maladie d'Alzheimer Alzheimer disease - Canada National policies, reports and guidelines
PubMed/Medline Epidemiology Abstracts of selected papers
Creese J, Bédard M, Brazil K, Chambers L. Sleep disturbances in spousal caregivers of individuals with Alzheimer's disease. Int Psychogeriatr.
2008 Feb;20(1):149-61. Epub 2007 Apr 30.
BACKGROUND: Although sleep problems are commonly reported among dementia caregivers, the nature and frequency of caregiver sleep disruptions, and their relationship to health status, has received little empirical attention to date. METHODS: The current study investigated the sleep situations of a sample of 60 spousal caregivers currently residing with a Alzheimer disease care recipient, including the frequency of nocturnal disruptions by the care recipient, and the reasons for these disruptions. In addition, exploratory correlations were computed between caregiver sleep variables and health outcomes. RESULTS: Some 63% of spousal caregivers reported sleep disruptions due to the nocturnal behavior of the recipients of their care. Poorer caregiver sleep quality was associated with higher frequency of nocturnal disruptions by the care recipient, the care recipient needing to use the bathroom, and wandering, higher caregiver depressive symptoms, and higher levels of caregiver role burden. The frequency of nocturnal disruptions was associated with poorer mental health status and a greater number of depressive symptoms. CONCLUSIONS: Results suggest that nocturnal disruptions by the care recipient may have adverse health consequences for spousal caregivers, and that further study of the determinants of caregiver sleep quality and health outcomes are warranted.
Tyas SL, Tate RB, Wooldrage K, Manfreda J, Strain LA. Estimating the incidence of dementia: the impact of adjusting for subject attrition using health care
utilization data. Ann Epidemiol. 2006 Jun;16(6):477-84.
PURPOSE: To estimate incidence rates for dementia and the impact of subject attrition on these rates. METHODS: Crude, age- and gender-specific incidence rates of dementia and Alzheimer's disease were calculated using person-years analysis and Cox proportional hazard models in a population-based cohort study of 1952 adults aged 65+ years in Manitoba, Canada. Rates were standardized to the nondemented population using the direct method. Ratios of incidence rates comparing completers to subjects who had died, refused, or were unavailable for follow up were based on health care utilization data (available for all subject groups) and used to adjust rates for attrition. RESULTS: Decedents had a significantly higher incidence of dementia than did subjects who completed the follow-up assessment. The incidence in subjects who refused or were unavailable at follow up was intermediate between decedents and completers. Adjusted for attrition, the standardized dementia incidence rate for community and institutional subjects was 25.3/1000 person-years, significantly higher than that based on follow-up assessments only (17.8/1000 person-years; 95% confidence interval: 14.3-21.4). CONCLUSIONS: The impact of loss to follow up on incidence rates varies depending on the reason for subject attrition. Incidence studies of dementia should develop strategies to characterize and address subject attrition to avoid underestimating disease incidence.
Lindsay J, Sykes E, McDowell I, Verreault R, Laurin D. More than the epidemiology of Alzheimer's disease: contributions of the Canadian Study of Health and
Aging. Can J Psychiatry. 2004 Feb;49(2):83-91.
OBJECTIVE: To highlight contributions to knowledge made by the Canadian Study of Health and Aging (CSHA). METHOD: The CSHA began in 1991, with follow-ups in 1996 and 2001. It was national in scope, with 18 study centres and a coordinating centre. It included 10 263 participants; of these, 9008 were in the community, and 1255 were in institutions. In each phase, community participants were screened for cognitive impairment, and where appropriate, cognitive status was determined by a detailed clinical examination. Data on possible risk factors for dementia were collected at baseline. Data on caring for people with dementia were collected in each phase. RESULTS: The prevalence of dementia was established at 8% of those aged 65 years and over; incidence (new cases each year) was about 2%. Cognitive impairment not dementia (CIND) was more than twice as common as dementia. Factors affecting the risk of institutionalization, mortality, and the health of caregivers were examined. The costs of dementia were conservatively estimated at dollar 3.9 billion in 1991. Risk factors for Alzheimer's disease (AD) and vascular dementia are presented; it is noteworthy that physical activity appeared to protect against all forms of cognitive decline, particularly for women. Clinical contributions include the development of norms for several neuropsychological tests. Other topics include the health of those with CIND, predicting dementia, medication use, frailty and healthy aging, and urinary incontinence. CONCLUSION: The CSHA has contributed substantially to knowledge of the epidemiology of dementia, including AD, and to many other topics relevant to seniors' health.
Bowerman JK. A learning perspective on caring: a view from the ground up. Int J Health Care Qual Assur Inc Leadersh Health Serv. 2004;17(1):xix-xxii.
In an interview, an adult learner with the Canadian School of Management discusses her research proposal aimed at strengthening the capability of the facility where she works to deal with clients suffering from Alzheimer's disease (AD) and other forms of dementia. The learner describes her motivation for this kind of work. She describes how she will apply some of the action learning principles recently learned to bring a mix of people together to discuss and work through issues relating to the care of clients residing in the Alzheimer unit. Canadian statistics suggest that at this time, one in three adults over the age of 85 and 1 in 13 over the age of 65 is affected with Alzheimer's or other forms of dementia. These numbers are expected to grow significantly as the population ages. The learner explains how, through her initiative, the facility will be more equipped to both meet the needs of current clients and those in the future.
Wolfson C, Wolfson DB, Asgharian M, M'Lan CE, Ostbye T, Rockwood K, Hogan DB; Clinical Progression of Dementia Study Group. A reevaluation of the duration
of survival after the onset of dementia. N Engl J Med. 2001 Apr 12;344(15):1111-6.
BACKGROUND: Dementia shortens life expectancy; estimates of median survival after the onset of dementia have ranged from 5 to 9.3 years. Previous studies of people with existing dementia, however, may have underestimated the deleterious effects of dementia on survival by failing to consider persons with rapidly progressive illness who died before they could be included in a study (referred to as length bias). METHODS: We used data from the Canadian Study of Health and Aging to estimate survival from the onset of symptoms of dementia; the estimate was adjusted for length bias. A random sample of 10,263 subjects 65 years old or older from throughout Canada was screened for cognitive impairment. For those with dementia, we ascertained the date of onset and conducted follow-up for five years. RESULTS: We analyzed data on 821 subjects, of whom 396 had probable Alzheimer's disease, 252 had possible Alzheimer's disease, and 173 had vascular dementia. For the group as a whole, the unadjusted median survival was 6.6 years (95 percent confidence interval, 6.2 to 7.1). After adjustment for length bias, the estimated median survival was 3.3 years (95 percent confidence interval, 2.7 to 4.0). The median survival was 3.1 years for subjects with probable Alzheimer's disease, 3.5 years for subjects with possible Alzheimer's disease, and 3.3 years for subjects with vascular dementia. CONCLUSIONS: Median survival after the onset of dementia is much shorter than has previously been estimated.
Ostbye T, Hill G, Steenhuis R. Mortality in elderly Canadians with and without dementia: a 5-year follow-up. Neurology. 1999 Aug 11;53(3):521-6.
OBJECTIVES: Based on the national Canadian Study of Health and Aging (CSHA), to compare 5-year overall mortality and causes of death in elderly with and without dementia. To determine how frequently dementia was mentioned on the death certificate. METHODS: For people who underwent a clinical examination in 1991 (n = 2,923), overall and cause-specific mortality rate ratios were calculated by dementia status (AD; vascular dementia; other dementias/other cognitive impairment; and normal cognition), age group (65 to 74, 75 to 84, 85+ years), and sex, using the Canadian general population as the reference. Similar rate ratios were calculated for people in the community who screened negative for cognitive impairment and who did not undergo a clinical examination (n = 7,340). Among elderly diagnosed as having AD or vascular dementia through the CSHA and who later died, it was determined how frequently dementia was recorded on the death certificate. RESULTS: The subgroup without cognitive dysfunction had a survival rate similar to that of the overall Canadian population except in the oldest age group, where the survival rate was better than that of the general population, which includes people with dementia. People in the three groups with cognitive impairment had a poorer survival in all age/sex groups than those without cognitive impairment and the general Canadian population. The most common causes of death in all groups were from vascular diseases. People with vascular dementia had the highest relative mortality rates for heart and cerebrovascular disease. Most of the AD groups also had high relative vascular system mortality rates. Among patients clinically diagnosed with AD, only 14.3% had any dementing illness recorded as the underlying cause of death; 41.8% had any dementing illness recorded anywhere on the death certificate. For vascular dementia, the corresponding numbers were 5.8% and 23.3%. CONCLUSION: Elderly with dementia have clearly increased mortality rates relative to elderly without cognitive impairment in all age/sex categories. People with vascular dementia have a particularly poor prognosis. Studies of AD and vascular dementia using death certificate data will grossly underestimate the proportions of elderly with these diseases.
Bowler JV, Munoz DG, Merskey H, Hachinski V. Fallacies in the pathological confirmation of the diagnosis of Alzheimer's disease. J Neurol Neurosurg Psychiatry.
1998 Jan;64(1):18-24.
OBJECTIVE: Necropsy confirmed clinical diagnostic accuracy for Alzheimer's disease is claimed to exceed 90%. This figure contains two fallacies; it includes cases in which Alzheimer's disease exists with other diseases affecting cognition and the studies that report these figures excluded cases without necropsy (verification bias). The effect of these errors is estimated. METHODS: Data were taken from the University of Western Ontario Dementia Study, a registry of dementia cases with clinical and psychometric follow up to necropsy based in a university memory disorders clinic with secondary and tertiary referrals. Data were available on 307 patients; 200 (65%) had clinically diagnosed Alzheimer's disease, 12 (4%) vascular dementia, 47 (15%) mixed dementia, and 48 (16%) had other diagnoses. One hundred and ninety two of 307 cases (63%) died and 122 of 192 fatalities (64%) had necropsies. The pathological material was interpreted in two ways, allowing and disallowing coexistent disease in making a diagnosis of Alzheimer's disease. In cases without necropsy, progressive cognitive loss was used as a marker for degenerative dementia. The outcome measures of interest were the positive predictive value of a clinical diagnosis of Alzheimer's disease allowing and disallowing coexistent diseases and with and without correction for cases that were not necropsied. RESULTS: The clinical diagnoses differed significantly between the population who died and those who did not. In cases without necropsy, 22% had no dementia on follow up, concentrated in early cases and men, showing considerable scope for verification bias. The positive predictive value of a diagnosis of Alzheimer's disease was 81% including coexistent diseases, falling to 44% when limited to pure cases. Combined, these factors reduce the positive predictive value to 38% for pure Alzheimer's disease. CONCLUSIONS: Correction for dual pathology and verification bias halves the positive predictive value of the clinical diagnosis of Alzheimer's disease. Data derived from necropsy studies cannot be extrapolated to the whole population. This has important implications including uncertainty about diagnosis and prognosis and a dilution effect in therapeutic trials in Alzheimer's disease.
The Canadian Study of Health and Aging: risk factors for Alzheimer's disease in Canada. Neurology. 1994 Nov;44(11):2073-80.
OBJECTIVE: To study risk factors for Alzheimer's disease (AD) based on data from the Canadian Study of Health and Aging. DESIGN: Population-based case-control study. SETTING: Communities and institutions in 10 Canadian provinces. PARTICIPANTS: Two hundred fifty-eight cases clinically diagnosed with probable AD, with onset of symptoms within 3 years of diagnosis, and 535 controls, frequency matched on age group, study center, and residence in community or institution, clinically confirmed to be cognitively normal. MAIN OUTCOME MEASURE: Odds ratios (ORs) were calculated using unconditional logistic regression for previously hypothesized and potential risk factors for AD. RESULTS: The OR for family history of dementia was significantly elevated (2.62; 95% confidence interval [CI], 1.53 to 4.51) and increased with the number of relatives with dementia. Those with less education were at higher risk of AD, with an OR of 4.00 (95% CI, 2.49 to 6.43) for those with 0 to 6 years, in comparison with those with 10 or more years. Head injury achieved borderline significance. A history of arthritis resulted in a low risk of AD (OR = 0.54; 95% CI, 0.36 to 0.81), as did a history of use of nonsteroidal anti-inflammatory drugs. Initial analyses showed an increased risk of AD for occupational exposure to glues as well as to pesticides and fertilizers; the increased risk was greater in those with less education. CONCLUSION: This study confirmed a number of previously reported risk factors for AD, but provided little support for others. A new finding was an increased risk for those with occupational exposure to glues as well as pesticides and fertilizers, but this needs further study.
Hogan DB, Thierer DE, Ebly EM, Parhad IM. Progression and outcome of patients in a Canadian dementia clinic. Can J Neurol Sci. 1994 Nov;21(4):331-8.
Five hundred and fifty-three patients were referred to a Canadian dementia clinic for standardized evaluation. The majority (83.5%) had a dementia with Alzheimer's disease (AD) accounting for 89% of dementias. Patients with probable AD who were followed for five years had variable rates of progression, increased mortality (37.1%, 2.5 times the expected rate) and a high rate of institutionalization (79%). Simple demographic (age) and social factors (marital status) were strong predictors for institutionalization. It was extremely difficult at presentation to predict the rate of progression. The prevalence of AD in autopsied cases was 62.5%. Clinic patients were younger, had milder dementias, and were more likely to have AD than patients identified in the course of a contemporaneous population-based dementia prevalence study.
Ebly EM, Parhad IM, Hogan DB, Fung TS. Prevalence and types of dementia in the very old: results from the Canadian Study of Health and Aging. Neurology. 1994
Sep;44(9):1593-600.
We report on the prevalence of dementia in Canadians age 85 years and older. The purpose of this study was to determine whether the prevalence of dementia continued to increase in the very old, and to define the types of dementia and their relative proportions in this age group. We collected data as part of the Canadian Study of Health and Aging (1990 to 1992), which consisted of a sample of 1,835 subjects from a population of 283,510 Canadians who were 85 years of age and older residing in the community or in institutions. The prevalence of dementia in the 85 years and older group was 28.5%, more than twice that of the 75- to 84-years cohort. The prevalence of dementia of 23% in the 85- to 89-years sample (n = 1,332) increased to 40% in the 90 to 94 years group (n = 371) and, in the 95 years and older sample (n = 104), reached 58%. Overall, Alzheimer's disease (AD; probable or possible) accounted for 75% of all dementias; a vascular etiology alone accounted for 13% of dementias. The proportion of clinically diagnosed AD cases to vascular dementia cases increased significantly after age 65 and was higher in the 85+ group than in a younger cohort (65 to 84 years).
Rockwood K, Stadnyk K. The prevalence of dementia in the elderly: a review. Can J Psychiatry. 1994 Jun;39(5):253-7.
We reviewed the findings of the Canadian Study of Health and Aging in the context of studies published between January 1986 and June 1993 that documented dementia and Alzheimer's disease prevalence. Studies were identified using a MEDLINE literature search. Additional references were selected from the bibliography of identified articles. Most reports of all types of dementia prevalence are within a narrow range for each of the age groups 65+, 75+ and 85+ years. By contrast, two recent reports on the prevalence of Alzheimer's disease have reported much higher estimates (10.3% and 15.3%) in the elderly (65+ years). A variety of threats to both validity and generalizability of the estimates are present in all studies. In community studies which employed clinical interviews most subjects were only mildly affected; the natural history of impairment of this group requires further study if the consequences of these findings are to be understood. There is important variability in the definition of the functional consequences of cognitive impairment in the elderly which affects both the diagnosis and staging of dementia.
Gautrin D, Froda S, Tetreault H, Gauvreau D. Canadian projections of cases suffering from Alzheimer's disease and senile dementia of Alzheimer type over the
period 1986-2031. Can J Psychiatry. 1990 Mar;35(2):162-5.
Alzheimer's disease (AD) is characterized by irreversible changes in cognitive and intellectual functions, accompanied by progressive memory loss, and described by neurochemical and neuropathological impairments. The classic term Alzheimer's disease applies to presenile dementia, while all of the syndromes that share the distinctive signs of AD are known as senile dementia of the Alzheimer type (SDAT). In Canada, as in several other industrialized countries, we are seeing a rapid growth of the elderly population. The renewed interest in AD and SDAT is partly attributable to the view that the increasing percentage of sufferers will have a significant socioeconomic impact. Few attempts have been made to project the number of cases of SDAT in Canada. In assessing the prevalence of SDAT in an over 65 population, a rate of 2.5% (or 3%) is commonly applied. This rate corresponds to one half the estimated prevalence rate for all severe types of dementia, using an average of the rates arrived at by some ten studies. The authors dispute this approach: i. the assumption that 50% of dementia cases will be AD is not verified for all populations; ii. the use of a single prevalence rate for everyone over age 65 is rather uninformative; and iii. the combining of results from various sources is questionable given the possible lack of consistency in the following respects: diagnostic criteria, methods of investigation, effort made to recruit cases, and representativeness of the groups studied. In this article, prevalence rates by age group have been inferred based on two Finnish studies conducted in the 1980s on the prevalence of AD in the general population. Economics Abstracts of selected papers
Gagnon M, Rive B, Hux M, Guilhaume C. Cost-effectiveness of memantine compared with standard care in moderate-to-severe Alzheimer disease in Canada. Can J
Psychiatry. 2007 Aug;52(8):519-26.
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.
Feldman H, Gauthier S, Hecker J, Vellas B, Hux M, Xu Y, Schwam EM, Shah S, Mastey V; Donepezil MSAD Study Investigators Group. Economic evaluation of donepezil
in moderate to severe Alzheimer disease. Neurology. 2004 Aug 24;63(4):644-50.
OBJECTIVE: To investigate the costs to society of Alzheimer disease (AD) care in a multinational, randomized, placebo-controlled trial of donepezil in patients with moderate to severe AD. METHODS: A total of 290 patients with AD (screening standardized Mini-Mental State Examination score 5 to 17) were randomized to receive either donepezil (n = 144; 5 mg/day for 28 days, followed by 10 mg/day as per clinician's judgment) or placebo (n = 146) for 24 weeks. The authors collected data on patient and caregiver health resource utilization prospectively using the Canadian Utilization of Services Tracking questionnaire. Costs were calculated for patients and caregivers in each group based on resource utilization multiplied by the unit prices for each resource. A cost (the average Ontario minimum wage for 1998 [Can 6.85 dollars per hour]) was assigned to unpaid time that caregivers spent assisting the patient with activities of daily living (ADL). RESULTS: Patient and caregiver demographics at baseline were similar across the two groups. After adjusting for baseline total cost per patient, the mean total societal cost per patient for the 24-week period was donepezil, Can 9,904 dollars (US 6,686 dollars) and placebo, Can 10,236 dollars (US 6,910 dollars). This net cost saving of Can 332 dollars (US 224 dollars) included the average 24-week cost of donepezil treatment. Most of the cost-saving with donepezil treatment was due to less use of residential care by patients, and caregivers spending less time assisting patients with ADL. CONCLUSION: This cost-consequence analysis reveals economic benefits of treatment of moderate to severe AD with donepezil.
Getsios D, Caro JJ, Caro G, Ishak K; AHEAD Study Group. Assessment of health economics in Alzheimer's disease (AHEAD): galantamine treatment in Canada. Neurology.
2001 Sep 25;57(6):972-8.
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.
Baladi JF, Bailey PA, Black S, Bouchard RW, Farcnik KD, Gauthier S, Kertesz A, Mohr E, Robillard A. Rivastigmine for Alzheimer's disease: Canadian interpretation
of intermediate outcome measures and cost implications. Clin Ther. 2000 Dec;22(12):1549-61.
BACKGROUND: Clinical studies have shown that patients with Alzheimer's disease (AD) who are treated with rivastigmine have statistically significantly better scores on 5 scales used to assess AD than control patients receiving placebo. However, the clinical meaning and cost implications of these differences are not clear. OBJECTIVE: The purpose of this study was to assess the clinical meaning and cost implications of statistically significant results obtained in clinical trials of rivastigmine for the treatment of AD. Potential cost implications for the health care system, caregivers, and society are considered. METHODS: Data on clinical effects of rivastigmine were obtained from published North American and European clinical studies of patients with mild to moderately severe AD receiving rivastigmine 6 to 12 mg/d (n = 828) or placebo (n = 647). Differences in scores on the Alzheimer's Disease Assessment Scale-Cognitive Function, Clinician's Interview-Based Impression of Change with both clinical and caregiver information considered, Progressive Deterioration Scale, Mini-Mental State Examination (MMSE), and Global Deterioration Scale were assessed. A convenience panel of 9 Canadian specialists experienced in the treatment of AD provided their opinions on the clinical importance of the trial results. Chart review was performed to identify specific behaviors that improved, and cost implications of improvements were assessed. RESULTS: The panel determined that statistically significant differences in scores on all scales except the MMSE were likely associated with functional or cognitive differences that were clinically relevant for patients, reflecting stabilization that would have beneficial consequences for caregivers and health care resource use. Subsequent chart review showed that improvement on specific scale items confirmed the physician panel's opinion. Analysis of possible cost implications to society indicated that medication expenditures would be offset largely by delays in the need for paid home care and institutionalization, positive effects on caregiver health, and less time lost from work for the caregiver. CONCLUSIONS: From the perspective of a Canadian specialist panel, rivastigmine treatment for AD produces clinically relevant effects for patients that are beneficial to caregivers. These effects suggest decreased use of caregiver resources and delays in the need for institutionalization, both of which reduce societal costs.
Hauber AB, Gnanasakthy A, Mauskopf JA. Savings in the cost of caring for patients with Alzheimer's disease in Canada: an analysis of treatment with rivastigmine.
Clin Ther. 2000 Apr;22(4):439-51.
OBJECTIVE: To estimate per-patient potential cost savings using rivastigmine in the treatment of Alzheimer's disease (AD) in Canada. BACKGROUND: In recent years, new members of a class of pharmaceuticals known as cholinesterase inhibitors have been introduced for the treatment of patients with AD. Two recent studies conducted in the United Kingdom and the United States estimated potential cost savings from the new cholinesterase inhibitor rivastigmine. The present study combined the disease-progression model used in those 2 studies with Canadian costs to estimate per-patient potential savings resulting from the treatment of AD in Canada. METHODS: Efficacy data from 2 pivotal, phase III clinical trials of rivastigmine were used in a hazard model of disease progression to estimate long-term differences in cognitive functioning between patients receiving rivastigmine and patients receiving no treatment. We used the Mini-Mental State Examination (MMSE) score as our measure of disease progression. We also used Canadian costs of AD care, estimated as a function of MMSE score, to estimate cost savings experienced by treated patients compared with patients receiving no treatment. All costs and cost savings are presented in 1997 Canadian dollars. We used a societal perspective in this analysis. RESULTS: Rivastigmine was estimated to delay the transition to more severe stages of AD by up to 188 days for patients with mild AD after 2 years of treatment. For patients with mild-to-moderate and moderate disease, this delay was estimated to be 106 and 44 days, respectively. For patients with the mild stage of AD, estimated average daily cost savings (excluding the cost of rivastigmine) ranged from Can $0.45 per patient per day at 6 months to Can $6.44 per patient per day after 2 years of treatment. For all patients, these estimated average daily cost savings ranged from a low of Can $0.71 per patient per day after 6 months of treatment to a high of Can $4.93 per patient per day after 2 years. CONCLUSION: On average, treatment with rivastigmine yields savings in the direct cost of caring for AD patients that exceed the cost of the drug after 2 years of treatment.
O'Brien BJ, Goeree R, Hux M, Iskedjian M, Blackhouse G, Gagnon M, Gauthier S. Economic evaluation of donepezil for the treatment of Alzheimer's disease in
Canada. J Am Geriatr Soc. 1999 May;47(5):570-8.
BACKGROUND: Donepezil is a new drug recently approved in the United States and Canada for the treatment of Alzheimer's disease (AD). We estimated the cost-effectiveness of donepezil 5 mg daily as an adjunct to usual care in the management of persons with mild-to-moderate AD defined as a Mini-Mental Health State Examination (MMSE) score in the range 10 to 26. METHODS: Treatment effect data as MMSE change-over-baseline scores were obtained from a 30-week placebo-controlled trial of donepezil. MMSE scores beyond observed trial data were estimated using a Markov model with 10 cycles of 24 weeks based on the placebo MMSE progression observed in the trial. Data from AD subjects in the Canadian Study of Health and Aging were used to estimate costs of nursing home care, community services, medications, and caregiver time as a function of MMSE score. A clinic-based cohort study from Alberta was used to estimate the distribution of AD patients by MMSE score presenting for treatment. The effectiveness measure for the economic model was expected time (over 5 years) spent with nonsevere AD (MMSE > or = 10). RESULTS: Over 5 years of treatment, donepezil is predicted to reduce health care costs by CA$929 per patient but increase caregiver time costs by CA$48 per patient for an overall cost saving to society of CA$882 per patient. Patients not receiving donepezil are predicted to spend 2.21 years of the 5 years in nonsevere AD compared with 2.41 years for treated patients (a gain of just over 2 months). Sensitivity analysis reveals that cost savings per patient increase if more AD patients are assumed to survive to 5 years; however, if donepezil treatment continues when patients' MMSE score falls below 10, the incremental cost is higher for treatment at CA$1554 per patient. CONCLUSION: Based on the limited available data, our model predicts that the use of donepezil for mild-to-moderate AD in Canada is associated with lower 5-year costs and less time spent with severe AD when compared with the alternative of usual care with no donepezil therapy. As more reliable long-term data become available, these predictions should be confirmed and/or updated.
Hux MJ, O'Brien BJ, Iskedjian M, Goeree R, Gagnon M, Gauthier S. Relation between severity of Alzheimer's disease and costs of caring. CMAJ. 1998 Sep 8;159(5):457-65.
BACKGROUND: Data from the Canadian Study of Health and Aging (CSHA) were used to examine the relation between severity of Alzheimer's disease, as measured by the Mini-Mental State Examination (MMSE), and costs of caring. METHODS: The CSHA was a community-based survey of the prevalence of dementia, including subtypes such as Alzheimer's disease, among elderly Canadians. Survey subjects with a diagnosis of possible or probable Alzheimer's disease were grouped into disease severity levels of mild (MMSE score 21-26), mild to moderate (MMSE score 15-20), moderate (MMSE score 10-14) and severe (MMSE score below 10). Components of care available from the CSHA were use of nursing home care, use of medications, use of community support services by caregivers and unpaid caregiver time. Costs were calculated from a societal perspective and are expressed in 1996 Canadian dollars. RESULTS: The annual societal cost of care per patient increased significantly with severity of Alzheimer's disease. The cost per patient was estimated to be $9451 for mild disease, $16,054 for mild to moderate disease, $25,724 for moderate disease and $36,794 for severe disease. Institutionalization was the largest component of cost, accounting for as much as 84% of the cost for people with severe disease. For subjects living in the community, unpaid caregiver time and use of community services were the greatest components of cost and increased with disease severity. INTERPRETATION: The societal cost of care of Alzheimer's disease increases drastically with increasing disease severity. Institutionalization is responsible for the largest cost component. Alzheimer disease and related disorders associations
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