Disparities in the treatment of dementia among medicare beneficiaries

Copyright 2008 by The Gerontological Society of America Racial and Ethnic Disparities in the Treatment of Ilene H. Zuckerman, Priscilla T. Ryder, Linda Simoni-Wastila, Thomas Shaffer, Masayo Sato, Lirong Zhao, and Bruce Stuart Lamy Center on Drug Therapy and Aging, Department of Pharmaceutical Health Services Research, University of Maryland School of Pharmacy, Baltimore.
Objectives. Numerous studies have documented disparities in health care utilization between non-Hispanic White and minority elders. We investigated differences in anti-dementia medication use between non-Hispanic White and minoritycommunity-dwelling Medicare beneficiaries with dementia.
Methods. Using multivariate analysis with generalized estimating equations, we estimated prevalence ratios (PRs) for anti-dementia medication use by race/ethnicity for 1,120 beneficiaries with dementia from years 2001 through 2003 ofthe Medicare Current Beneficiary Survey.
Results. After adjusting for demographics, socioeconomics, health care access and utilization, comorbidities, and service year, we found that anti-dementia medication use was approximately 30% higher among non-HispanicWhites compared to other racial/ethnic groups (PR ¼ 0.73, 95% confidence interval [CI] ¼ 0.59, 0.91). As for individualracial/ethnic groups, prevalence disparities remained significant for non-Hispanic Blacks (PR ¼ 0.75, 95% CI ¼ 0.57,0.99) and non-Hispanic others (PR ¼ 0.50, 95% CI ¼ 0.26, 0.96) but were attenuated for Hispanics (PR ¼ 0.84, 95%CI ¼ 0.59, 1.20).
Discussion. Results provide evidence that racial/ethnic disparities in utilization of drugs used to treat dementia exist and are not accounted for by differences in demographic, economic, health status, or health utilization factors. Findingsprovide a foundation for further research that should use larger numbers of minority patients and consider dementia typeand severity, access to specialty dementia care, and cultural factors.
Key Words: Dementia—Health disparities—Anti-dementia medication—Medicare beneficiaries.
I N general, disease burden falls disproportionately on are more likely to be undiagnosed or misdiagnosed relative to minority populations. Even at older ages, minorities tend non-Hispanic Whites (Clark et al., 2005; Leo, Narayan, Sherry, to have poorer health status, whether measured by disease Michalek, & Pollock, 1997); however, with population-based incidence, prevalence, or severity (National Center for Health sampling and careful diagnostic techniques employing neuro- Statistics, 2007). Eliminating health disparities is one of two psychological and laboratory testing following National In- overarching goals of Healthy People 2010 (U.S. Department of stitute of Neurological and Communicative Disorders and Health and Human Services, 2000), the disease prevention and Stroke–Alzheimer’s Disease and Related Disorders Association health promotion agenda of the U.S. Department of Health and (NINCDS-ADRDA) criteria, the prevalence of dementia may Human Services. The Institute of Medicine’s 2002 ground- be relatively higher in minority populations. One community- breaking report Unequal Treatment: Confronting Racial and based survey, with diagnoses confirmed using clinical testing Ethnic Disparities in Health Care (Smedley, Stith, & Nelson, and NINCDS-ADRDA criteria, found the prevalence of 2003) and the National Healthcare Disparities Report (Agency Alzheimer’s disease among African American men to be 2.5 for Healthcare Research and Quality, 2006) documented times greater than the prevalence among non-Hispanic White disparities in health care access. Disparities extend to inequal- men (Demirovic et al., 2003). Both non-Hispanic Blacks and ities in access to medications. Older minorities are less Latinos transition to long-term care at more advanced stages of likely than majority elders to utilize prescription drugs or to dementia (Stevens et al., 2004; Yaffe et al., 2002).
increase their numbers of prescriptions over time (Briesacher, Minorities also may be less likely to be prescribed anti- dementia medications. One study found that, considered Dementia is a chronic and serious disease, with an estimated together, minority patients (non-Hispanic Blacks, Asians, and worldwide societal cost of $315.4 billion in 2005 (Wimo, Latinos) in Alzheimer’s disease research centers in California Winblad, & Jonsson, 2007). According to findings from the had 40% lower odds of acetylcholinesterase inhibitor use 2002 Medicare Current Beneficiary Survey (MCBS), approx- compared to Whites (Mehta, Yin, Resendez, & Yaffe, 2005).
imately 3.4 million Medicare beneficiaries are diagnosed with Thus, there may be racial/ethnic disparities in dementia Alzheimer’s disease and related disorders, more than half of incidence, prevalence, access to health care services, and whom (approximately 2 million) live in the community (Gruber-Baldini, Stuart, Zuckerman, Simoni-Wastila, & Miller, The U.S. Food and Drug Administration has approved two 2007; Stuart et al., 2007). Non-Hispanic Blacks with dementia classes of drugs to treat symptoms of cognitive deficit in RACIAL DISPARITIES IN DEMENTIA MEDICATION Alzheimer’s disease and related disorders: cholinesterase proxy report (‘‘sample person ever told had Alzheimer’s inhibitors (donepezil, rivastigmine, galatamine, and tacrine) disease or dementia’’). We determined dementia status from and an N-methyl-D-aspartate receptor antagonist (memantine).
claims alone for 49.9% of respondents, from self-reports only Using a national data set of community-dwelling Medicare for 23.7%, and from both sources for 26.4%. We chose beneficiaries, we investigated the use of these prescription anti- covariates from a literature review and from preliminary dementia medications to compare prevalence by non-Hispanic analysis. Covariates included age (less than 65 years, 65–74, 75–84 and 85 years and older), gender, U.S. census region,residence in a metropolitan statistical area, income, education,marital status, source of dementia diagnosis (claims data, self-/ proxy report, or both), source of survey information (self-reportor proxy respondent for at least half of the interviews), prescription drug insurance coverage, use of other medication The study sample consisted of 1,606 person-years of classes, and year of observation. We estimated comorbid observation of 1,120 community-dwelling Medicare beneficia- disease burden by using a count of comorbid disease classes.
ries with a reported diagnosis of dementia from the MCBS foryears 2001 through 2003. The MCBS is a continuous sampleof U.S. Medicare recipients conducted by the Centers for Medicare & Medicaid Services. Although the use of sampling We compared use or nonuse of anti-dementia medications by weights for single years of the MCBS would allow it to be using chi-square tests and t tests. Multivariate analysis with nationally representative of Medicare beneficiaries, we could generalized estimating equations (GEE) estimated the condi- not use weights in our analysis because individuals may have tional effect of race/ethnicity on anti-dementia drug use, crossed years. Furthermore, because the MCBS oversamples controlling for the covariates listed above. This analysis yielded certain groups (e.g., those younger than 65 years of age), our prevalence ratios (PRs) rather than prevalence odds ratios. With unweighted sample was not necessarily representative of 26% of the sample using medication, odds ratios would not Medicare beneficiaries as a whole. The MCBS uses a rotating have been an accurate estimation of actual prevalence. Odds panel design; beneficiaries or their proxies are interviewed in ratios are always further from the null value of 1.0 with the their homes three times per year for a maximum of 4 years by disparity increasing with higher prevalence (Rothman & using computer-assisted personal interviewing technology.
Greenland, 1998). GEE is especially useful for investigations Respondents are asked a battery of questions relating to with binary outcomes and correlated data. With efficient demographic characteristics, health status, pharmaceutical and parameter estimation and accurate standard errors, GEE is other health care utilization and expenditures, and health better at correcting for clustering and other types of correlation insurance coverage. The MCBS links survey information to (Hanley, Negassa, Edwardes, & Forrester, 2003). Standard Medicare Parts A and B claims that contain diagnostic errors are recalibrated to account for similarity of measures, or indicators as well as payment information. We excluded 42 correlation, by the same individual across differing lengths of observations from the analysis because of a missing value; all observation (Fitzmaurice, Laird, & Ware, 2004). Logistic observations analyzed had complete information.
regression analysis is less suited to this analysis. Logisticregression does not consider nonindependence due to correla-tion; it also yields prevalence odds ratios rather than PRs and thus would have overestimated the association of race/ethnicity The dependent variable was the annual prevalence of use of and medication use. We assumed a binomial distribution and any anti-dementia medication, namely donepezil (AriceptÒ), used a log link function to report PRs. We calculated PRs and rivastigmine (ExelonÒ), galantamine (RazadyneÒ/ReminylÒ), or their associated 95% confidence intervals (CIs) by using PROC memantine (NamendaÒ), by non-Hispanic Whites and minori- GENMOD in SAS 9.1.3 (Deddens, Petersen, & Lei, 2003).
ties. Respondents self-reported medication use. In addition to Because the usual tests of model fit are not valid for GEE querying respondents about specific medications used, inter- models, we assessed goodness of fit by using an experimental viewers reviewed medication containers as part of the thrice- technique based on aggregates of residuals with an associated yearly in-home interview during Years 2, 3, and 4. Respondents p value of .9060, indicating a satisfactory model (SAS Institute, were asked to keep all medication containers, insurance slips, and receipts for medications, and the interviewers reviewed thesematerials at each interview. If a medication named in a previousround of interviewing was not listed, the respondent was queried about its use during the period. Thus, prescription fills were The ethnic/racial distribution of the sample was 76.3% non- recorded, but actual medication use was not observed. We Hispanic White, 11.7% non-Hispanic Black, 8.1% Hispanic, determined race/ethnicity, our variable of interest, from the self- and 3.8% non-Hispanic other (see Table 1). The mean age report from the in-home computer-assisted personal interview- of the sample was 80 years (SD ¼ 11), and nearly 60% ing interview. We determined dementia diagnosis status from were female. Approximately 26% of the sample received at the presence of International Classification of Diseases–9 least one anti-dementia medication, most commonly donepezil codes 331.0, 331.1, 331.2, 331.7, 290.xx (excluding 290.8 and and less frequently rivastigmine, galantamine, or memantine.
290.9), 294.xx (excluding 294.9), or 794.xx on one or more The sample differed significantly by race for anti-dementia inpatient hospital, skilled nursing facility, home health, hospital medication use, age, income, education, marital status, region, outpatient, or physician supplier/carrier claim or from self-/ urban residence, and proxy response. Whites most often used Table 1. Characteristics of the Sample by Racial/Ethnic Group (N ¼ 1,120) White (n ¼ 855; 76.3%) Black (n ¼ 131; 11.7%) (n ¼ 91; 8.1%) Other (n ¼ 43; 3.8%) (N ¼ 1,120) Use of any anti-dementia drug (p ¼ .0022) Proxy respondent for half or more interviews (p ¼ .0011) Notes: FPL ¼ federal poverty level; MSA ¼ metropolitan statistical area; SNF ¼ skilled nursing facility.
aCardiovascular, antidepressant, or antipsychotic medication.
p ! .05 except where shown.
anti-dementia medication (28.7%, p ¼ .0022), were in the urban metropolitan areas (91.2%, p , .0018), lived in the South highest income group (27.7%, p , .0001), had education (68.1%, p , .0001), and had a proxy respondent for at least half beyond high school (35.1%, p , .0001), and were currently of the interviews (57.1%, p ¼ .0011).
married (45.6%, p , .0001); Hispanics most often were In addition to the race/ethnicity comparisons shown in younger than 65 years of age (19.8%, p , .0001), lived in Table 1, we also performed bivariate comparisons between RACIAL DISPARITIES IN DEMENTIA MEDICATION Table 2. Multivariate Analysis of Prevalence Ratios for Table 3. Multivariate Analysis of Prevalence Ratios for Anti-Dementia Medications for Non-Hispanic Anti-Dementia Medications for Non-Hispanic White Versus Minority Medicare Beneficiaries Note: Non-Hispanic Whites is the reference group. PR ¼ prevalence ratio; anti-dementia medication users and nonusers (data not shown).
Compared to those not receiving anti-dementia medication, anti-dementia medication users were older (M ¼ 81.3 years vs 79.7, t ¼ À2.89, p ¼ .0040), were more often currently married (53.6% vs 38.5%, v2 ¼ 40.2, p , .0001), used more cardiovascular (80.1% vs 74.1%, v2 ¼ 4.2, p ¼ .0401) and antidepressant medications (38.1% vs 29.1%, v2 ¼ 8.2, p ¼ .0041), more frequently had prescription drug insurance (79.4% vs 71.1%, v2 ¼ 7.6, p ¼ .0058), and were more likely to have their dementia status ascertained both from claims data and from self-report (52.2% vs 17.4%, v2 ¼ 134.7, p , .0001).
Relative to nonusers, anti-dementia medication users were less likely to use the services of hospitals (27.9% vs 40.4%, v2 ¼ 14.6, p ¼ .0001), hospices (2.1% vs 6.9%, v2 ¼ 9.4, p ¼ .0022), or skilled nursing facilities (7.2% vs 15.0%, v2 ¼ 11.5, p ¼ .0007). They were also less likely to live in poverty (13.1% vs 27.0%, v2 ¼ 24.7, p , .0001). There were no other significant differences between medication users and nonusers.
We compared the prevalence of anti-dementia medication by racial/ethnic group (see Table 2). In the unadjusted model, the PR comparing all minorities to non-Hispanic Whites was 0.61 (95% CI ¼ 0.48, 0.77). The adjusted model included de- mographics (gender, age, marital status, and geographic location), socioeconomic status (income and education), source of diagnosis (claims data, self-report, or both), self- or proxy reporting, comorbidity count, health care utilization variables (prescription insurance status, hospital, skilled nursing facility and hospice stay, use of other drug classes), and year. The PR final model, urban or suburban residence (PR ¼ 1.30, 95% CI ¼ 1.09, 1.57) and use of other drug classes (PR ¼ 1.50, 95% CI ¼ 1.16, 1.95) were associated with higher prevalence of use.
Being never married, divorced, or separated (PR ¼ 0.33, 95% CI ¼ 0.17, 0.61); having a single source for dementia diagnosis (PR ¼ 0.37, 95% CI ¼ 0.31, 0.44, for claims data only; PR ¼ Notes: PR ¼ prevalence ratio; CI ¼ confidence interval; FPL ¼ federal 0.35, 95% CI ¼ 0.28, 0.44, for self-report only); being a proxy respondent rather than a self-report (PR ¼ 0.82, 95% CI ¼ 0.71, a85 years or older is the reference group.
0.95); lacking supplemental prescription insurance coverage (PR ¼ 0.76, 95% CI ¼ 0.63, 0.92); and using hospice services cGreater than 300% FPL is the reference group.
d (PR ¼ 0.49, 95% CI ¼ 0.27, 0.89) predicted lower prevalence Postsecondary education is the reference group.
of anti-dementia drug use. We repeated the analyses with Currently married is the reference group.
individual minority racial/ethnic groups entered simultaneously Diagnosis from both claims data and self-report is the reference group.
g11 or more comorbid conditions is the reference group.
in both models (see Table 3). Prevalence disparities remained hCardiovascular, antidepressant, or antipsychotic medications.
significant for non-Hispanic Blacks (PR ¼ 0.75, 95% CI ¼ 0.57, 0.99) and non-Hispanic others (PR ¼ 0.50, 95% CI ¼ 0.26,0.96) but were attenuated for Hispanics (PR ¼ 0.84, 95% CI ¼0.59, 1.20).
of the Alzheimer’s type, anti-dementia medications were Relative to non-Hispanic Whites, community-dwelling indicated for use in only mild to moderate disease during our minority Medicare beneficiaries with dementia had an ap- study years (U.S. Food and Drug Administration, 2003); proximately 30% lower prevalence of anti-dementia medication therefore, medication might have been considered inappropriate use in the years 2001 through 2003. The finding of lower for community-dwelling minority elders with more advanced prevalence among minority Medicare beneficiaries was ex- tremely robust, persisting even after we adjusted for demo- Non-Hispanic Blacks make proportionately more mental graphic, economic, health status, health care access, and health visits to primary care providers rather than to special- utilization factors. Our findings are similar in magnitude to ists and thus receive fewer prescriptions for psychotropics the 40% lower prevalence for non-Whites found by Mehta and (Snowden, 2001). Poorer access to specialty dementia care may colleagues (2005) in their investigation of acetylcholinesterase explain some of the disparity with regard to dementia medi- inhibitor use in California Alzheimer’s disease centers in the cations. In addition, non-Hispanic Blacks have higher relative years 1999 through 2003. Our study reinforces their findings by rates of vascular dementia, and medications considered in this using a national community-dwelling sample rather than one investigation were approved for use in Alzheimer’s disease from a specialty clinical setting. When we examined racial/ rather than for vascular and other types of dementia during the ethnic groups individually, PRs remained statistically signifi- study years. Thus, non-Hispanic Blacks in particular may havereceived proportionately fewer prescriptions for anti-dementia cant for non-Hispanic Blacks and non-Hispanic others but lost medications, because the use of these medications was not significance for Hispanics, possibly because of the small indicated for dementia types other than Alzheimer’s disease.
numbers in each minority group. Of interest is that the smallest However, even if taken together, it seems unlikely that group, the heterogeneous ‘‘non-Hispanic other’’ category, had dementia type and disease severity could account for the entire the greatest disparity in prevalence. In our sample, the 43 non- 30% differential between majority and minority use of anti- Hispanic others included those reporting more than one race/ ethnicity (n ¼ 16), Asian or Pacific Islander (n ¼ 15), North Our study has several limitations. Specific anti-dementia American native (n ¼ 7), don’t know (n ¼ 3), and other (n ¼ 2).
medications and their indications changed within the study Numbers were too small within this group to determine whether years 2001 through 2003 and continue to do so; therefore, prevalence was similar across these subcategories or whether findings relating to this class of medications during those years one or two subcategories strongly influenced the disparity.
may not hold true for the present or future. Numbers within Although we cannot fully explain this disparity from our each specific race/ethnicity group were relatively small; thus, investigation, our findings suggest that between-race differ- our ability to look at individual groups is limited. We lacked ences are not due to demographic, economic, health status, information on caregivers of people with dementia. Caregiver access, or utilization variables. Disparities may be due to factors may have influenced access to health care for people differences in attitudes toward dementia in diverse cultures in with dementia; for instance, caregiver psychological distress is the United States, as well as cultural bias in cognitive associated with a decreased likelihood of receipt of influenza measurement (Manly & Espino, 2004). They might arise also vaccine by the person being cared for (Thorpe et al., 2006).
from differences in psychosocial environment (e.g., neighbor- Issues of disparities need investigation using data sources hood effects) or discrimination experienced by members of that contain higher numbers of minorities, thereby allowing for minority groups, both of which have been proposed to be detailed examination of prevalence and use patterns by specific important determinants of the mental health of non-Hispanic racial and ethnic populations. Further investigation needs to be Blacks (Williams & Earl, 2007). If dementia is less often undertaken with larger numbers of minority participants, correctly diagnosed in minorities, as reported by Clark and accounting for issues of dementia type and severity, medication colleagues (2005) and Leo and associates (1997), our disparity dose and duration of use, access to specialty dementia care, and findings may underestimate the unmet treatment need among consistency in treatment disparities across settings of care. As minorities with dementia that has not been diagnosed.
well, dementia prevalence is greatest in nursing homes and Differences in prescribing patterns for non-Hispanic Whites other institutions, and evaluation of racial and ethnic disparities and other groups might arise in several ways. Minority patients should be considered in this vulnerable population, especially have relatively poorer access to health care, beyond the because a recent study reported significant racial disparities in variation in hospital, skilled nursing facility, and hospice use quality nursing home placement (Smith, Feng, Fennell, Zinn, & and prescription drug insurance coverage accounted for by this Mor, 2007). Additionally, the influence of cultural and analysis (Smedley et al., 2003). Less contact with physicians environmental factors in dementia treatment remains a fertile would likely result in fewer prescriptions being written. In our sample, non-Hispanic Whites had an average of 7.7 office visitsduring the observation period, whereas minorities made 6.9 visits; this difference is nearly statistically significant at the a ¼ This study was funded by a Grant 20050634 from the Commonwealth .05 level (t ¼À1.90, p ¼ .058). Additionally, minority elders are Fund. Dr. Zuckerman was supported by Award K01AG22011 from the placed in long-term care at more advanced stages of dementia National Institute on Aging. Dr. Ryder was supported by Training Grant (Stevens et al., 2004; Yaffe et al., 2002), perhaps leading to T32AG000262 in the epidemiology of aging from the National Institute onAging. We are grateful for the assistance of Dr. Ann L. Gruber-Baldini and a disproportionate number of more severely demented minority the helpful comments of three anonymous reviewers. A previous version of elders remaining in the community. With the exception of this work was presented at the AcademyHealth Annual Research Meeting, memantine, approved in 2003 for moderate to severe dementia RACIAL DISPARITIES IN DEMENTIA MEDICATION I. H. Zuckerman planned the study, wrote and revised the manuscript, Mehta, K. M., Yin, M., Resendez, C., & Yaffe, K. (2005). Ethnic supervised data analysis and interpretation, and performed data analysis and differences in acetylcholinesterase inhibitor use for Alzheimer disease.
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