Cost of Illness of Alzheimer's Disease

Cost of Illness of Alzheimer’s Disease: How Useful Are Current Estimates?

Bernard S. Bloom, PhD,1 Nathalie de Pouvourville,2 3 and Walter L. Straus, MD, MPH Downloaded from https://academic.oup.com/gerontologist/article/43/2/158/636148 by guest on 27 September 2021

Purpose: The goal of this literature review was to Cost-of-illness (COI) studies are useful to un- determine the validity and policy relevance of recent derstand the economic burden of illness on patients, estimates from many countries of Alzheimer’s disease families, health care systems, payers, and society. (AD) costs. Design and Methods: We searched They are the economic equivalent of epidemiological surveys of prevalence, incidence, and natural history Medline and other databases for English-language of a disease, and they are typically the initial step in peer-reviewed journals on total, direct, indirect, and an economic evaluation. per case cost of AD that used 1985–2000 data. We The burdens of Alzheimer’s disease (AD) on health adjusted costs of U.S. studies for inflation. We care systems, families, and social services are widely adjusted non-U.S. studies by that country’s medical recognized in the scientific and popular literature. cost inflation rate and purchasing power parity (PPP). Since AD is a disease of senescence, population aging Results: Of 71 studies identified, 21 met all criteria ensures increasing prevalence and intensifying chal- for inclusion. Annual inflation adjusted U.S. total costs lenges for policy makers (Brookmeyer, Gray, & of AD varied from $5.6 billion to $88.3 billion. AD Kawas, 1998; Jorm, Korten, & Henderson, 1987; total per case (direct and indirect) costs varied from Lobo et al., 2000; Ritchie, Kildea, & Robine, 1992; $1,500 to $91,000; indirect/family costs varied Trabucchi, 1999). Current U.S. estimates of preva- from $3,700 to $21,000. Among non-U.S. studies, lence range from 1.09 to 4.58 million people, affecting between 2.7% and 11.2% of the population aged older AD annual adjusted per case costs varied from PPP than 65 years (Brookmeyer et al., 1998; Trabucchi, $2,300 to PPP $30,000. Cost variation was due to 1999). Prevalence is estimated to increase nearly four- diverse study methods, data sources, services fold to between 4.2 and 15.4 million whereas annual included, and lack of clear differentiation between incidence is expected to rise from 360,000 new cases in cost of AD and cost of caring for people with 1997 to 1.14 million in 2047 (Brookmeyer et al.). As AD. Implications: The cost of AD is high, although prevalence increases, so will expenditures for this reliable estimates are not available. Costs are likely to chronic and progressive disease for multiple family, rise given expected demographic shifts in all coun- medical, social, and community resources (Ernst & tries. The widely variable cost estimates call into Hay, 1997; Meek, McKeithan, & Schumock, 1998). question the real costs of Alzheimer’s disease and However, reported annual U.S. estimates of AD cost their applicability to policy initiatives. vary five-fold, from $20 billion to $100 billion (Ernst & Hay, 1994; Leon, Cheng, & Neumann, 1998; Key Words: Alzheimer’s disease, Dementia, Cost, Menzin, Lang, Friedman, Neumann, & Cummings, Economics 1999; Rice et al., 1993; Schumock, 1998). A majority of costs are for long-term care, reduced function, and family care giving (Ernst & Hay, 1994, 1997; Max, Webber, & Fox, 1995; Rice et al., 1993). Funded, in part, by a grant from Aetna/US Healthcare Foundation. Most people with AD are elderly and often have We acknowledge the able assistance of Kathryn A. Kvam, Nicolas multiple high-cost diagnoses. Thus, allocating pre- Renaud, and Suzanne Vogel. cisely direct, indirect, and nonmedical costs of AD Address correspondence to Bernard S. Bloom, University of Pennsylvania, Department of Medicine, Division of Geriatrics, 3615 across all diagnoses for the same person is particu- Chestnut Street, Philadelphia, PA 19104-2676. E-mail: bsbloom@ larly difficult. This is the problem of joint product, mail.med.upenn.edu 1Department of Medicine, Division of Geriatrics, University of wherein it is difficult to attribute specific medical Pennsylvania, Philadelphia. services and their costs, in part or in whole, to each 2Universite´ de Paris V, Hoˆpital Cochin, Paris, France. 3Outcomes Research and Management, Merck & Company, West diagnosis. Accurate attribution is especially prob- Point, PA. lematic in estimating AD costs as there are few, only

158 The Gerontologist modestly efficacious medical treatments with mainly currency, adjusted for their inflation rates (1982– short-term effects (Winblad & Wimo, 1999). 1984 5 100). Further, we adjusted costs across The goal of this study was to examine the countries to U.S. dollars by purchasing power parity usefulness of published cost-of-illness estimates of (PPP) for the year of each country’s data (World AD. Accurate cost data are fundamental for in- Bank Group, 2000). PPP is a technique that allows formed policy and clinical decisions by patients, for accurate comparisons across countries of income physicians, and payers to meet clinical, quality-of- and cost of purchasing goods and services. For life, and economic objectives. example, a metric can be the number of hours a person must work to purchase a kilowatt of electricity or an ambulatory physician visit. PPP is accepted as the most accurate way to measure the Methods ability of the currency of one country to purchase We searched Medline, Econlit, and related com- goods and services in other countries. puterized databases from 1 January 1985 through 31 Downloaded from https://academic.oup.com/gerontologist/article/43/2/158/636148 by guest on 27 September 2021 December 2000, by using the following search terms: Alzheimer’s, dementia, economics, and cost (as well Results as all variations). Visual search of bibliographies of We identified 71 studies, 46 from the United States published articles identified additional studies not and 25 from other countries. We excluded 50 studies; found by Medline searches. Three reviewers in- 29 did not meet entry criteria—eight had population dependently abstracted each study. Disagreements samples less than 100 patients, 4 had too few cost were resolved among the reviewers. Studies had to categories (e.g., only ambulatory medical costs), 8 meet all of the following criteria for inclusion: used data from before 1985, and 1 showed savings only. Thus, we included 21 studies for review. 1. Most study patients with dementia were diagnosed with AD. 2. Cost data were from 1 January 1985 through Definition of Alzheimer’s Disease 31 December 2000. 3. Studies had to enroll at least 100 patients. We used each study’s authors’ definition of AD. 4. Study had to be published in an English- Fourteen studies included all types of dementia in their language peer-reviewed journal. analysis. Four studies used secondary sources like paid claims data and relied on ICD recorded coding We compared results and conclusions of all studies, (Gutterman, Markowitcz, Lewis, & Fillit 1999; examining similarities and differences in study Menzin et al., 1999; Taylor & Sloan, 2000; Weiner, methods, data collected, cost-calculation processes, Powe, Weller, Shaffer, & Anderson, 1998). Four sources used, and cost estimates. We collected studies relied on the Mini-Mental State Examination epidemiological estimates of AD prevalence and (Hux et al., 1998; Østbye & Crosse, 1994; Rice et al., incidence. We collected or calculated from each study 1993; Soueˆtre, Thwaites, & Yeardley, 1999), two used annual total and costs per person with AD (per case National Institute of Neurological and Communica- costs); we calculated incremental costs of AD for tive Diseases and Stroke criteria (Kronborg-Andersen controlled studies. Costs attributable to AD, or any et al., 1999; Leon et al., 1998), and one used results of diagnosis, are difficult to estimate in the face of a randomized control trial (O’Brien et al., 1999). Five multiple diagnosis. For example, it is nearly impos- studies gave no specific source of disease definition. sible to separate the components of an ambulatory Adjustment for AD severity was made in 10 studies visit or an inpatient stay into those costs specifically (Ernst & Hay, 1997; Kinosian et al., 2000; Kronborg- attributable to each diagnosis for the individual Andersen et al., 1999; Leon et al., 1998; Max et al., patient. The best alternative is to estimate incremental 1995; Rice et al., 1993; O’Brien et al., 1999; Schneider, AD costs by examining in two comparable cohorts, Kavanaugh, Knapp, Beecham, & Netten, 1993; one with and one without AD, all costs of care. The Soûetre et al., 1999; Taylor & Sloan, 2000). Five differences (incremental) in costs can be defined as studies adjusted for comorbidity (Gutterman et al., those of AD. We found two types of controlled 1999; Kavanaugh & Knapp, 1999; Kinosian et al., studies—(a) those that measured costs in populations 2000; Leon et al., 1998; Menzin et al., 1999). with and without AD, and (b) those that compared costs of care for people with AD living in an Medical and Cost Data Collected institution to people with AD living in the community. For all studies, the total number of people with There was wide variability of cost data items AD was the denominator. For U.S. studies, we across studies. Additionally, service definitions were adjusted costs by sector specific (e.g., hospital, not uniform. For example, hospital costs may have pharmaceuticals) medical care price indices, 1982– included, individually or in varying combinations, 1984 5 100 (U.S. Bureau of the Census, 1999). Non- acute, short-term, long-term, mental, and/or rehabil- U.S. study costs were expressed in that country’s itation inpatient care. Indirect costs for activities like

Vol. 43, No. 2, 2003 159 Table 1. Annual Cost Per Case of Alzheimer’s Disease, U.S. and Non-U.S.-Controlled Studies (Adjusted for Inﬂation, 1982–1983 5 100, and Purchasing Power Parity)

Study Annual Total Cost Per Case Direct Medical Nursing Home Indirect/Family

AD vs. No AD U.S. Max et al. (1995) 5,052 638 4,414 Weiner et al. (1998) 1,547 1,547 Taylor & Sloan (2000) 1,759 1,658 78 101 Gutterman et al. (1999) 2,683 2,683 Non-U.S. Østbye & Crosse (1994) 10,175 389 7,767 2,019 Soueˆtre et al. (1999) 27,675 5,123 3,595 18,956 Kronborg-Andersen et al. (1999) 3,630 506 3,123 Downloaded from https://academic.oup.com/gerontologist/article/43/2/158/636148 by guest on 27 September 2021 O’Brien et al. (1999) 79,822 44,098a 12,388 Nursing Home vs. Community Living U.S. Rice et al. (1993) 18,106 70 23,905 5,809 Max et al. (1995) 16,832 504 7,937 7,568 Non-U.S. Kavanaugh & Knapp (1999) 3,395 2599 3,420 574 Note: Values are 5-year cost. aCombined direct medical plus nursing home cost. caregiver time were estimated by opportunity cost or (Schneider et al., 1993). Some differences were replacement cost methods, and different average clearly related to individual study definition of wages were used for each cost estimation process. dementia. U.S. studies with narrowly defined AD Finally, primary and secondary data sources often led to lowest prevalence of 1.5 million (Ernest & were intermingled. Hay, 1994), and more inclusive diagnoses of all types of dementia to 4.3 million (Rice et al., 1993). But as Data Sources about 70% of all types of dementia are estimated as Alzheimer’s type, the large variation is not well Eight studies were of national or large populations accounted for by multiple dementia diagnoses. (Coon & Edgerly, 1999; Gray & Fenn, 1993; Hux et al., 1998; Kavanaugh & Knapp, 1999; O’Brien et al., 1999; O’Shea & Reilly, 2000; Taylor & Sloan, 2000; Cost of Alzheimer’s Disease—Adjusted for Wimo, Karlsson, Sandman, Corder, & Winblad, Inflation and Purchasing Power Parity 1997), and the other 13 were of selected or random population samples. Thirteen (63.8%) studies used Controlled Studies.—Four of the eight control secondary data sources. Some used national data, studies comparing cost of care for people with and like U.S. Medicare, or from all of Sweden, and some without AD were of U.S. populations (Gutterman et regional data like those from northern California al., 1999; Menzin et al., 1999; Taylor & Sloan, 2000; Medicaid. Weiner et al., 1998), two were from Canada (O’Brien Among the 11 control studies, 8 used matched et al., 1999; Østbye & Crosse, 1994), and one each cohort designs, and 1 was based on a previously from the United Kingdom (Soueˆtre et al., 1999) and published randomized control trial. Eight of the Denmark (Kronborg-Andersen, 1999; Table 1). After control studies compared costs of persons with AD adjusting for inflation among U.S. studies, and with costs of those without AD and 3 estimated inflation and PPP among non-U.S. studies, annual incremental cost of people with AD living in the incremental AD costs across control studies varied community compared with those in nursing home. from about $1,500 (Weiner et al.) to $79,000 per case Age and gender were the most common matching (O’Brien et al.). criteria in all control studies. The 3 studies comparing persons with AD living in nursing home or community found incremental Prevalence of Alzheimer’s Disease annual adjusted costs of PPP $3,400 (Kavanaugh & Knapp, 1999) to PPP $18,000 (Rice et al., 1993; Table Wide ranges of AD prevalence estimates charac- 1). Two U.S. studies had similar cost estimates, terized all studies; the greatest was observed in U.S. perhaps because both examined similar northern studies, 1.5 million to 4.3 million people (Ernst & California populations (Max et al., 1995; Rice, Hay, 1994; Rice et al., 1993). In England, there were 1993). However, in the 1993 Rice and colleagues’ two-fold prevalence variations, 370,000 and 730,000 study, incremental indirect and/or family cost was

160 The Gerontologist Table 2. Annual Cost Per Case of Alzheimer’s Disease, U.S. and Non-U.S.-Uncontrolled Studies (Adjusted for Inﬂation, 1982–1983 5 100, and Purchasing Power Parity)

Study Annual Total Cost Per Case Direct Medical Nursing Home Indirect/Family U.S. Ernst & Hay (1994) 19,797 1,716 4,498 13,582 Leon et al. (1998) 12,125 9,607a 2,518 Kinosian et al. (2000) 45,289 19,716 8,372 7,198 Huang et al. (1998) 91,044 43,136 39,352 11,265 Weinberger et al. (1993) 26,640 6,952 19,688 Non-U.S. Hux et al. (1998) 9,698 7,827 Wimo et al. (1998) 30,000 11,213 16,087 2,700 Cavallo & Fattore (1997) 1,996 36,827 Downloaded from https://academic.oup.com/gerontologist/article/43/2/158/636148 by guest on 27 September 2021 Gray & Fenn (1993) 2,316 602 1,507 66 O’Shea & O’Reilly (2000) 5,590 423 1,838 3,329 aCombined direct medical plus nursing home cost.

$12,377 greater, and in the 1995 Max and colleagues’ and/or family costs (Table 2). Among non-U.S. study, nursing home cost was nearly $16,000 less for studies, per capita costs varied 3-fold, long-term community-living than institutionalized persons. institutionalization expenditures 2-fold, and family Much of the cost variance across studies was due costs more than 10-fold. to differences in types of care cost collected. For The study with the highest AD cost estimated example, four studies did not collect nursing home inflation-adjusted U.S. costs for 4.28 million people and/or indirect and/or family costs (Gutterman et al., at $41 billion, or $91,000 per case (Huang et al., 1999; Kronborg-Andersen et al., 1999; Menzin et al., 1998). Direct medical costs were 47.4% of the total 1999; Weiner et al., 1998; Table 1). In one U.S. study, and included short- and long-stay hospitalizations, nursing home care was 87.4% of per capita costs but physician and other provider services, and pre- no indirect and/or family costs were collected scription pharmaceuticals; nursing home care was (Menzin et al., 1999). In one Canadian study, nursing 43.2% and indirect and/or family care was 9.4% of home care was 76.3% of annual costs and indirect total costs. and/or family expenses were 19.8% of costs (Østbye & Crosse, 1994). One high-cost British study found an annual cost of PPP $27,675 per case; it collected direct medical, nursing home, and indirect expenses Discussion (family out-of-pocket cost, caregiver time away from Aging populations mean the prevalence of AD employment plus reduced work productivity); the will increase. As prevalence rises, so will expendi- latter expenditures represented 71.3% of estimated tures. Accurate estimates of societal, medical, and costs (Soueˆtre et al., 1999). nonmedical AD costs are vital to planning and implementing AD policies, from basic science re- Uncontrolled Studies.—Studies without control search to end-of-life care. populations exhibited the widest range of annual per The singular finding of this study is the widely case AD costs, and with even less consistency among divergent annual per case cost estimates of AD specific sectors costs than for controlled studies ($1,500–$91,000 per case), with inflation-adjusted (Table 2; Cavallo & Fattore, 1997; Ernst & Hay, U.S. estimates ranging from $5.6 billion to $88 1994; Gray & Fenn, 1993; Huang, Cartwright, & billion per year. Controlled and uncontrolled studies Teh-Wei, 1998; Hux et al., 1998; Kinosian et al., have similar cost variability irrespective of country. 2000; Leon et al., 1998; O’Shea & O’Reilly, 2000; Similar wide cost variations were found in an Weinberger et al., 1993; Wimo, Karlsson, et al., extensive review of 110 U.S. inflation adjusted cost- 1997). Annual inflation-adjusted costs per case of-illness studies across 80 diagnoses (Bloom, Bruno, among U.S. studies varied from about $12,000 (Leon Maman, & Jayadevappa, 2001) and of a review of et al., 1998) to $91,000 (Huang et al., 1998; Table 2). diabetes mellitus cost-of-illness studies specifically Among non-U.S. studies, inflation- and PPP-adjusted (Pagano, Brunetti, Tediosi, & Garattini, 1997). Both annual per case costs varied from PPP $2,300 studies concluded that low quality of methods and (Weinberger et al., 1993) to PPP $30,000 (Wimo, study design were the most important factors for Karlsson, et al., 1998). cost variations and low quality scores. The present There was 20-fold variation in per patient direct intensive case study of AD confirms the findings of medical costs among uncontrolled U.S. studies, and the earlier studies. This AD study provides addi- five-fold differences in nursing home and indirect tional opportunities to examine causes of variation

Vol. 43, No. 2, 2003 161 in costs because there are a relatively large number care at home more costly or similar to institution- of published studies, care for people with AD is alized care, all controlled studies find institutional expensive, and direct and indirect costs are frequent- care more costly than home care. Comorbid ly estimated. conditions may explain some of the higher hospital Diversity of cost components collected and and physician costs of AD patients compared with methods of monetarizing cost also have important those without AD. For example, incremental med- effects. For example, for studies that measured ication costs between those with and without AD, indirect and/or family costs, some used actual or however, were less than $300 per year in any mean wages to value time lost from work and others country, supporting the findings on incremental used opportunity cost. In addition, variable esti- medication costs of Rice and colleagues (1993). mates of Medicare cost may be due to the fact that Finally, when similar methods and populations are Medicare data appear to underreport diagnoses and used, irrespective of country and controlled and overreport payments for AD (Newcomer, Clay, uncontrolled design, similar results are produced Luxenberg, & Miller, 1999). Such inconsistencies (Kinosian et al., 2000; Max et al., 1995; O’Brien et al., Downloaded from https://academic.oup.com/gerontologist/article/43/2/158/636148 by guest on 27 September 2021 are likely problems related to joint product—the 1999; Rice et al., 1993). A simulation analysis from difficulty of distributing costs accurately across the Netherlands (McDonnell et al., 2001) that was diagnoses during an episode of illness, especially published after our analysis was complete and that for studies without control populations. used similar methods to those of O’Brien and Multiple study enrollment processes (i.e., pre- colleagues (1999) and Kinosian and colleagues cision of AD diagnosis) confounded results. There is (2000), found 10-year results comparable to both frequently inadequate differentiation between cost these studies. of AD by controlled studies and cost of caring for Some researchers contend cost of illness studies people with AD from uncontrolled designs even offer little to decision makers and may lead to after estimating costs per case and adjusting all costs inadequate policies because of poor data, lack of to a common index. As a consequence of variations outcomes results, or no incremental analysis (Drum- in disease definition and case ascertainment, the mond, O’Brien, Stoddart, & Torrance, 1997). distributions of disease severity for AD and other However, there are criteria for executing COI studies diseases may vary substantially among population- (Drummond et al., 1997; Jefferson, Demichelli, & based studies, and between population studies and Mugford, 2000), many of which are fulfilled in a few those using selected samples. of the studies we reviewed (e.g., Kinosian et al., 2000; Despite expectations of decreased costs under O’Brien et al., 1999). Unfortunately, adherence with managed care, their per case expenditures are nearly these guidelines is inconsistent within studies. Meth- two-fold greater than those of nonmanaged care, odological standards, though, tend to be less without appreciable differences in type of services frequently discussed or debated for COI than for included or methods used (Taylor & Sloan, 2000; cost-effectiveness studies (Gold, Siegel, Russell, & Weiner et al., 1998). But to the contrary, Rice and Weinstein, 1996). Inadequate studies thus are due colleagues (1993), found that annual hospitalization mainly to lack of implementation of existing stand- costs for AD added $504 per person for an additional ards. This burden is added to the central AD 1.34 inpatient days per annum and $233 for 7.8 more problem: Lack of a uniformly accepted definition of physician visits, both paid mainly by Medicare (Rice AD and of a gold standard diagnostic test contribute and colleagues). Prescription pharmaceuticals added to highly variable incidence, prevalence, and cost $185 per year. estimates. Thus, future studies of AD COI should The challenge of AD cost variability is com- include available performance methodological stand- pounded by variability of epidemiological estimates ards for epidemiological, clinical, and economic of AD incidence and prevalence. Lack of agreement evaluations. Further, they should be long-term cohort on the definition of AD and absence of consensus on studies samples starting perhaps at age 55. Such a gold standard diagnostic test necessarily leads to studies would likely require 10–15 years to complete. inconsistent criteria for diagnosing and coding AD Some parts of such a study are already underway, for and likely contributes to four-fold differences in U.S. example, the AHEAD study that measures indirect AD prevalence estimates. and family costs of AD. Despite the wide cost variations we are able to discern common patterns across studies. Long-term care and family costs are the most important Limitations determinants of total cost. AD patients have higher direct and indirect costs than people without AD. The most important limitation of this study is the Costs increase with disease severity and decline of inability to estimate clearly effects of individual any activity of daily living. When those with mild or factors that contribute to variability of AD cost moderate AD severity are cared for at home, indirect results. An inability to disentangle joint product costs are higher than in nursing home. Although among all services compounds this problem some uncontrolled U.S. and non-U.S. studies find (Drummed et al., 1997). Few of the studies adjusted

162 The Gerontologist for comorbidity, which appears to lead to over- review of the literature. Alzheimer Disease & Associated Disorders, 11(Suppl. 6), 135–145. estimating incremental AD cost (Lee, Meyer, & Gold, M. R., Siegel, J. E., Russell, L. B., & Weinstein, M. C. (1996). Cost- Clouse, 2000). In addition, we could not test effectiveness in health and medicine. Oxford, England: Oxford accurately for factors associated with cost variation University Press. Gray, A., & Fenn, P. (1993). Alzheimer’s disease: The burden of illness in because of small cell sizes relative to the number of England. Health Trends, 25, 31–37. independent variables. Third, limiting reviews to Gutterman, E. M., Markowitcz, J. S., Lewis, B., & Fillit, H. (1999). Cost of English-language studies may introduce bias even in Alzheimer’s disease and related dementia in managed-Medicare. Journal of the American Geriatrics Society, 47, 1065–1071 the face of our including English language studies Huang, L.-F., Cartwright, W. S., & Teh-Wei, H. (1998). The economic cost from non-English speaking countries. Finally, as of senile dementia in the United States. Public Health Reports, 103, 3–7. with any literature review we could only review the Hux, M. J., O’Brien, B. J., Iskedjian, M., Goeree, R., Gagnon, M., & Gauthier, S. (1998). Relation between severity of Alzheimer’s disease publication, not the actual study. A poor evaluation and costs of caring. Canadian Medical Association Journal, 159, 457– may be due to inadequate method or analysis, 465. incomplete reporting by the authors, or space limits Jefferson, T., Demicheli, V., & Mugford, M. (2000). Elementary economic evaluation in health care (2nd ed.). London: BMJ Books. Downloaded from https://academic.oup.com/gerontologist/article/43/2/158/636148 by guest on 27 September 2021 by the journal. Jorm, A. F., Korten, A. E., & Henderson, A. S. (1987). The prevalence of dementia: A quantitative integration of the literature. Acta Psychiatrica Scandinavica, 76, 465–479. Conclusion Kavanagh, S. K., & Knapp, M. (1999). Cognitive disability and direct care costs for elderly people. British Journal of Psychiatry, 174, 539–546. Kinosian, B. P., Stallard, E., Lee, J. H., Woodbury, M. A., Zbrozek, A. S., & COI studies offer estimates of current status of Glick, H. A. (2000). Predicting 10-year care requirements for older people a disease, measure changes over time (e.g., following with suspected Alzheimer’sdisease.Journal American Geriatrics introduction of new treatments) and generate new Society, 48, 631–638. Kronborg-Andersen, C., Søgaard, J., Hansen, E., Kragh–Sorensen, A., research hypotheses. Like clinical research, we find Hastrup, L., Andersen, J., et al. (1999). The cost of dementia in that controlled studies lead generally to more Denmark: The Odense study. Dementia and Geriatric Cognitive consistent estimates than uncontrolled ones. Disorders, 10, 295–304. Lee, D. W., Meyer, J. W., & Clouse, J. (2001). Implications of controlling for One problem that bedevils uncontrolled studies is comorbid conditions in cost-of-illness estimates: A case study of the difficulty of differentiating between cost of AD osteoarthritis from a managed care perspective. Value in Health, 4, and cost of all care for people with AD even when 329–334. Leon, J., Cheng, C.-K., & Neumann, P. J. (1998). Alzheimer’s disease care: authors attempt to separate services and costs into Costs and potential savings. Health Affairs, 17, 206–216. specific diagnoses. Second, controlled studies have Lobo, A., Launer, L. J., Fratiglioni, L., Andersen, K., Di Carlo, A., Breteler, a tighter distribution of total and individual sector M. M., et al. (2000). Prevalence of dementia and major subtypes in Europe: A collaborative study of population-base cohorts. Neurology, costs than uncontrolled studies, but an equally wide 54(Suppl. 5), S4–S9. per case cost distribution. Similar wide variation is Max, W., Webber, P., & Fox, P. (1995). Alzheimer’s disease: The unpaid found for epidemiological estimates of AD preva- burden of caring. Journal of Aging and Health, 7, 179–199. McDonnell, J., Redekop, W. K., van der Roer, N., Goes, E., Ruitenberg, A., lence and incidence. Next, AD cost variation nar- Bussbach, J. J. V., et al. (2001). The cost of treatment of Alzheimer’s rows across time and countries once we control for disease in the Netherlands. PharmacoEconomics, 19, 379–390. Meek, P. D., McKeithan, K., & Schumock, G. T. (1998). Economic inflation and PPP. Fourth, AD entails relatively low considerations in Alzheimer’s disease. Pharmacotherapy, 18(Pt. 2), direct medical costs because there are no highly 68–73. effective medical treatments that importantly alter Menzin, J., Lang, K., Friedman, M., Neumann, P., & Cummings, J. L. (1999). The economic cost of Alzheimer’s disease and related dementias symptoms or long-term natural history of disease. to the California Medicaid Program (‘‘Medi–Cal’’) in 1995. American However, social, family, and daily function changes, Journal of Geriatric Psychiatry, 7, 300–308. work loss, and early mortality make AD economi- Newcomer, R., Clay, R., Luxenberg, K. S., & Miller, R. H. (1999). Misclassification and selection bias when identifying Alzheimer’s disease cally burdensome. Of one thing we can be certain, solely from Medicare claims records. Journal American Geriatrics most if not all of future medical and nonmedical AD Society, 47, 215–219. costs will be higher than current ones in the absence O’Brien, B. J., Goeree, R., Hux, M., Iskedjian, M., Blackhouse, G., Gagnon, M., et al. (1999). Economic evaluation of donepezil for the treatment of of any effective prophylaxis or treatment. Alzheimer’s disease in Canada. Journal of the American Geriatrics Society, 47, 570–578. O’Shea, E., & O’Reilly, S. (2000). The economic and social cost of de- References mentia in Ireland. International Journal of Geriatric Psychiatry, 15, Bloom, B. S., Bruno, D. J., Maman, D., & Jayadevappa, R. (2001). Usefulness 208–218. of cost of illness studies in health care decision making. Pharmaco- Østbye, T., & Crosse, E. (1994). Net economic costs of dementia in Canada. Economics, 19, 207–213. Canadian Medical Association Journal, 151, 1457–1464. Brookmeyer, R., Gray, S., & Kawas, C. (1998). Projections of Alzheimer’s Pagano, E., Brunetti, M., Tediosi, F., & Garattini, L. (1997). Costs of disease in the United States and the public health impact of delaying diabetes: A methodological analysis of the literature. PharmacoEco- disease onset. American Journal of Public Health, 88, 1337–1342. nomics, 15, 583–595. Cavallo, M. C., & Fattore, G. (1997). The economic and social burden of Rice, D. P., Fox, P. J., Max, W., Webber, P. A., Lindeman, D. A., Hauck, W. Alzheimer disease on families in the Lombardy region of Italy. Alzheimer W., et al. (1993). The economic burden of Alzheimer’s disease care. Disease and Associated Disorders, 11, 184–190. Health Affairs Summer, 11, 164–176. Coon, D. W., & Edgerly, E. S. (1999). The personal and social consequences Ritchie, K., Kildea, D., & Robine, J. M. (1992). The relationship between age of Alzheimer’s disease. Genetic Testing, 3, 29–36. and the prevalence of senile dementia: A meta analysis of recent data. Drummond, M. F., O’Brien, B., Stoddart, G. L., & Torrance, G. W. (1997). International Journal of Epidemiology, 21, 763–769. Methods for the economic evaluation of health hare programs (2nd Schneider, J., Kavanaugh, S., Knapp, M., Beecham, J., & Netten, A. (1993). ed.). Oxford, England: Oxford University Press. Elderly people with advanced cognitive impairment in England. Resource Ernst, R. L., & Hay, J. W. (1994). The US economic and social costs of use and costs. Aging Society, 13, 27–50. Alzheimer’s disease revisited. American Journal of Public Health, 84, Schumock, G. T. (1998). Economic considerations in the treatment and 1261–1264. management of Alzheimer’s disease. American Journal of Health– Ernst, R. L., & Hay, J. W. (1997). Economic research on Alzheimer disease: A System Pharmacy, 55(Suppl. 20), S17–S21.

Vol. 43, No. 2, 2003 163 Soueˆtre, E., Thwaites, R. M., & Yeardley, H. M. (1999). Economic impact of Medicare utilization and expenditure patterns. Journal American Alzheimer’s disease in the UK. Cost of care and disease severity for non- Geriatrics Society, 46, 762–770. institutionalized patients with Alzheimer’s disease. British Journal of Wimo, A., Karlsson, G., Sandman, P. O., Corder, L., & Winblad, B. (1998). Psychiatry, 174, 51–55. Cost of illness due to dementias in Sweden. International Journal of Taylor, D. H., & Sloan, F. A. (2000). How much do persons with Alzheimer’s Geriatric Psychiatry, 12, 857–861. disease cost Medicare? Journal American Geriatrics Society, 48, 639–646. Winblad, B., & Wimo, A. (1999). Assessing the societal impact of acetyl- Trabucchi, M. (1999). An economic perspective on Alzheimer’s disease. cholinesterase inhibitor therapies. Alzheimer Disease and Associated Journal of Geriatric Psychiatry & Neurology, 12, 29–38. Disorders, 13(Suppl. 2), S9–S19. U.S. Bureau of the Census. (1999). Statistical abstract of the United States: World Bank Group. (2000). The 2000 world development indicators 1999 (119th ed.). Washington, DC: U.S. Government Printing Ofﬁce. (Version 4.2) [CD–ROM *Stars]. Washington, DC: International Bank Weinberger, M., Gold, D. T., Divine, G. W., Cowper, P. A., Hodgson, L. G., for Reconstruction and Development. Schreiner, M. S., et al. (1993). Expenditures in caring for patients with dementia who live at home. American Journal of Public Health, 83, 338–341. Received February 27, 2002 Weiner, M., Powe, N. R., Weller, W. E., Shaffer, T. J., & Anderson, G. F. Accepted September 6, 2002 (1998). Alzheimer’s disease under managed care: Implications from Decision Editor: Laurence G. Branch, PhD Downloaded from https://academic.oup.com/gerontologist/article/43/2/158/636148 by guest on 27 September 2021

164 The Gerontologist