Risks and Benefits of Clinical Diagnosis Around the Time of Dementia Onset.

Diagnostic delay in dementia is common in the U.S. Drivers of diagnostic delay are poorly understood, but appear related to misconceptions about dementia, stigma, concerns about autonomy, the nature of the diagnostic process, and provider-related factors. There is little quantitative evidence underlying cited risks and benefits of receiving a diagnosis around the time of dementia onset, including impacts on physical health, impacts on mental health, care partner interactions, costs of care, increased time for care planning, or earlier access to treatment. While various groups continue to push for reductions in diagnostic delay, realization of benefits and mitigation of harms will require new research on potential benefits and harms. Workforce and resource constraints, coupled with the expected growth in the number of persons living with dementia, may be a barrier to realization of potential benefits and mitigation of identified harms, which will require adequate access to providers, services, and supports.

Association Between Racial Segregation and COVID-19 Vaccination Rates.

OBJECTIVE: To examine the association between county-level Black-White residential segregation and COVID-19 vaccination rates. DESIGN: Observational cross-sectional study using multivariable generalized linear models with state fixed effects to estimate the average marginal effects of segregation on vaccination rates. SETTING: National analysis of county-level vaccination rates. MAIN OUTCOME MEASURE: County-level vaccination rates across the United States. RESULTS: We found an overall positive association between county-level segregation and the proportion population fully vaccinated, with a 6.8, 11.3, and 12.8 percentage point increase in the proportion fully vaccinated by May 3, September 27, and December 6, 2021, respectively. Effects were muted after adjustment for sociodemographic variables. Furthermore, in analyses including an interaction term between the county proportion of Black residents and the county dissimilarity index, the association between segregation and vaccination is positive in counties with a lower proportion of Black residents (ie, 5%) but negative in counties with the highest proportions of Black residents (ie, 70%). CONCLUSIONS: Findings highlight the importance of methodological decisions when modeling disparities in COVID-19 vaccinations. Researchers should consider mediating and moderating factors and examine interaction effects and stratified analyses taking racial group distributions into account. Results can inform policies around the prioritization of vaccine distribution and outreach.

Association of Military Employment With Late-Life Cognitive Decline and Dementia: A Population-Based Prospective Cohort Study.

INTRODUCTION: As the number of U.S. veterans over age 65 has increased, interest in whether military service affects late-life health outcomes has grown. Whether military employment is associated with increased risk of cognitive decline and dementia remains unclear. MATERIALS AND METHODS: We used data from 4,370 participants of the longitudinal Adult Changes in Thought (ACT) cohort study, enrolled at age 65 or older, to examine whether military employment was associated with greater cognitive decline or higher risk of incident dementia in late life. We classified persons as having military employment if their first or second-longest occupation was with the military. Cognitive status was assessed at each biennial Adult Changes in Thought study visit using the Cognitive Abilities Screening Instrument, scored using item response theory (CASI-IRT). Participants meeting screening criteria were referred for dementia ascertainment involving clinical examination and additional cognitive testing. Primary analyses were adjusted for sociodemographic characteristics and APOE genotype. Secondary analyses additionally adjusted for indicators of early-life socioeconomic status and considered effect modification by age, gender, and prior traumatic brain injury with loss of consciousness TBI with LOC. RESULTS: Overall, 6% of participants had military employment; of these, 76% were males. Military employment was not significantly associated with cognitive change (difference in modeled 10-year cognitive change in CASI-IRT scores in SD units (95% confidence interval [CI]): -0.042 (-0.19, 0.11), risk of dementia (hazard ratio [HR] [95% CI]: 0.92 [0.71, 1.18]), or risk of Alzheimer's disease dementia (HR [95% CI]: 0.93 [0.70, 1.23]). These results were robust to additional adjustment and sensitivity analyses. There was no evidence of effect modification by age, gender, or traumatic brain injury with loss of consciousness. CONCLUSIONS: Among members of the Adult Changes in Thought cohort, military employment was not associated with increased risk of cognitive decline or dementia. Nevertheless, military veterans face the same high risks for cognitive decline and dementia as other aging adults.

Medicare Hospice Policy Changes and Beneficiaries' Rate of Live Discharge and Length-of-Stay.

CONTEXT: The 2014 Improving Medicare Post-Acute Care Transformation (IMPACT) Act systemized audits of long hospice stays, and the 2016 two-tier payment system decreased daily reimbursement rates after 60 days of enrollment. Both aimed to reduce long stays. OBJECTIVES: Examine how live discharge rates and length of stay changed in relation to the policies. METHODS: We computed monthly hospice-level percent live discharges and length of stay using 2008-2019 Medicare hospice claims. We compared prepolicies trends and postpolicies trends overall, within Alzheimer's disease and related dementias (ADRD) patients, within lung cancer patients, and stratified by hospice ownership (for-profit vs. nonprofit/government-owned). RESULTS: We included 10,539,912 and 10,453,025 episodes of care in the analytical samples for live discharge and length of stay analyses, respectively. Overall percent live discharges declined during the prepolicies period (-0.13 percentage-points per month, 95% CI: -0.14, -0.12), but exhibited no significant change during the postpolicies period. Trends were driven primarily by for-profits, with similar patterns within ADRD and lung cancer patients. Overall, mean length of stay increased over time, with greater rate of increase during the postpolicies period (0.41 days per month, 95% CI: 0.39, 0.42) compared to the prepolicies period (0.12 days per month, 95% CI: 0.10, 0.14). Length-of-stay increased faster among ADRD patients, but changed minimally for lung cancer patients. CONCLUSION: Live discharge rates declined significantly during the prepolicies period, but plateaued after implementation of the policies, driven by changes in for-profits. However, the policies did not reduce length of stay, which increased at faster rates, suggesting that postpolicies excess live discharges were not restricted to long-stay patients.

Investigation of the association of military employment and Parkinson's disease with a validated Parkinson's disease case-finding strategy.

INTRODUCTION: Persons with military involvement may be more likely to have Parkinson's disease (PD) risk factors. As PD is rare, case finding remains a challenge, contributing to our limited understanding of PD risk factors. Here, we explore the validity of case-finding strategies and whether military employment is associated with PD. MATERIALS AND METHODS: We identified Adult Changes in Thought (ACT) study participants reporting military employment as their longest or second longest occupation. We used self-report and prescription fills to identify PD cases and validated this case-finding approach against medical record review. RESULTS: At enrollment, 6% of 5,125 eligible participants had military employment and 1.8% had prevalent PD; an additional 3.5% developed PD over follow-up (mean: 8.3 years). Sensitivity of our case-finding approach was higher for incident (80%) than prevalent cases (54%). Specificity was high (>97%) for both. Military employment was not associated with prevalent PD. Among nonsmokers, point estimates suggested an increased risk of incident PD with military employment, but the result was non-significant and based on a small number of cases. CONCLUSIONS: Self-report and prescription medications can accurately identify incident PD cases relative to the reference method of medical record review. We found no association between military employment and PD.

Evaluation of Federal Policy Changes to the Hospice Benefit and Use of Hospice for Persons With ADRD.

Importance: Hospice is an important end-of-life service for patients with Alzheimer disease and related dementias (ADRD). Objective: To determine whether hospice use among patients with ADRD changed in association with recent policies aimed at reducing hospice misuse and long hospice stays, an outcome that may have disproportionately affected patients with ADRD because of their lengthy end-of-life trajectories. Design Setting and Participants: This observational cross-sectional study used Medicare hospice claims data from Medicare hospice episodes of care beginning between July 2008 and December 2019 among Medicare hospice beneficiaries 65 years or older at time of enrollment. Data analysis was conducted between September 2019 and June 2021. Exposures: The 2014 Improving Medicare Post-Acute Care Transformation (IMPACT) Act, which systematized audits of hospices with a high proportion of long stays, and the 2016 2-tier payment system, which reduced daily reimbursement rates after 60 days. Main Outcomes and Measures: Monthly percentage of (1) new patient enrollees, (2) patient census, and (3) care days provided to patients with an ADRD code. Results: The sample included 11 124 992 unique hospice episodes between 2008 and 2019; mean (SD) patient enrollment age ranged from 82.0 (8.2) years to 82.8 (8.7) years; the percentage of male patients ranged from 40.5% to 42.7%, and the percentage of Black, Hispanic, and White patients ranged from 7.7% to 8.2%, 1.5% to 2.0%, and 86.2% to 88.8%, respectively, across years. The percentage of new enrollees with an ADRD code dropped significantly during the months of IMPACT passage (-1.42 percentage points; 95% CI, -2.13 to -0.71) and implementation (-1.98 percentage points; 95% CI, -2.70 to -1.26) but rose again during the following months. While no significant changes were observed at the time of 2-tier payment implementation (0.15 percentage points; 95% CI, -0.21 to 0.51), the average rate of increase during the subsequent period was slower (0.01 percentage points per month; 95% CI, 0-0.02) than in earlier periods (0.05; 95% CI, 0.04-0.06 during the baseline period). Similar patterns were observed for the percentage of patient census and care days provided to patients with an ADRD code. Conclusions and Relevance: The results of this cross-sectional study of Medicare hospice claims data suggested that recent Medicare policies were associated with immediate and lasting reductions in the share of patients receiving hospice care with an ADRD code compared with expectations from preimplementation trends. Future research should examine mechanisms through which hospices enacted change and consequences for quality of care.

The Associations of Dietary Copper With Cognitive Outcomes.

Dietary copper intake may be associated with cognitive decline and dementia. We used data from 10,269 participants of the Atherosclerosis Risks in Communities Study to study the associations of dietary copper intake with 20-year cognitive decline and incident dementia. Dietary copper intake from food and supplements was quantified using food frequency questionnaires. Cognition was assessed using 3 cognitive tests at study visits; dementia was ascertained at study visits and via surveillance. Multiple imputation by chained equations was applied to account for the missing information of cognitive function during follow-up. Survival analysis with parametric models and mixed-effect models were used to estimate the associations for incident dementia and cognitive decline, respectively. During 20 years of follow-up (1996-1998 to 2016-2017), 1,862 incident cases of dementia occurred. Higher intake of dietary copper from food was associated with higher risk of incident dementia among those with high intake of saturated fat (hazard ratio = 1.49, 95% confidence interval: 1.04, 1.95). Higher intake of dietary copper from food was associated with greater decline in language overall (beta = -0.12, 95% confidence interval: -0.23, -0.02). Therefore, a diet high in copper, particularly when combined with a diet high in saturated fat, may increase the risk of cognitive impairment.

Exposure to Air Pollution in Relation to Risk of Dementia and Related Outcomes: An Updated Systematic Review of the Epidemiological Literature.

BACKGROUND: Dementia is a devastating neurologic condition that is common in older adults. We previously reviewed the epidemiological evidence examining the hypothesis that long-term exposure to air pollution affects dementia risk. Since then, the evidence base has expanded rapidly. OBJECTIVES: With this update, we collectively review new and previously identified epidemiological studies on air pollution and late-life cognitive health, highlighting new developments and critically discussing the merits of the evidence. METHODS: Using a registered protocol (PROSPERO 2020 CRD42020152943), we updated our literature review to capture studies published through 31 December 2020, extracted data, and conducted a bias assessment. RESULTS: We identified 66 papers (49 new) for inclusion in this review. Cognitive level remained the most commonly considered outcome, and particulate matter (PM) remained the most commonly considered air pollutant. Since our prior review, exposure estimation methods in this research have improved, and more papers have looked at cognitive change, neuroimaging, and incident cognitive impairment/dementia, though methodological concerns remain common. Many studies continue to rely on administrative records to ascertain dementia, have high potential for selection bias, and adjust for putative mediating factors in primary models. A subset of 35 studies met strict quality criteria. Although high-quality studies of fine particulate matter with aerodynamic diameter ≤2.5µm (PM2.5) and cognitive decline generally supported an adverse association, other findings related to PM2.5 and findings related to particulate matter with aerodynamic diameter ≤10µm (PM10, NO2, and NOx) were inconclusive, and too few papers reported findings with ozone to comment on the likely direction of association. Notably, only a few findings on dementia were included for consideration on the basis of quality criteria. DISCUSSION: Strong conclusions remain elusive, although the weight of the evidence suggests an adverse association between PM2.5 and cognitive decline. However, we note a continued need to confront methodological challenges in this line of research. https://doi.org/10.1289/EHP8716.

Generalizability of findings from a clinical sample to a community-based sample: A comparison of ADNI and ARIC.

INTRODUCTION: Clinic-based study samples, including the Alzheimer's Disease Neuroimaging Initiative (ADNI), offer rich data, but findings may not generalize to community-based settings. We compared associations in ADNI to those in the Atherosclerosis Risk in Communities (ARIC) study to assess generalizability across the two settings. METHODS: We estimated cohort-specific associations among risk factors, cognitive test scores, and neuroimaging outcomes to identify and quantify the extent of significant and substantively meaningful differences in associations between cohorts. We explored whether using more homogenous samples improved comparability in effect estimates. RESULTS: The proportion of associations that differed significantly between cohorts ranged from 27% to 34% across sample subsets. Many differences were substantively meaningful (e.g., odds ratios [OR] for apolipoprotein E ε4 on amyloid positivity in ARIC: OR = 2.8, in ADNI: OR = 8.6). DISCUSSION: A higher proportion of associations differed significantly and substantively than would be expected by chance. Findings in clinical samples should be confirmed in more representative samples.

Trends in Relative Incidence and Prevalence of Dementia Across Non-Hispanic Black and White Individuals in the United States, 2000-2016.

Importance: In the US, dementia risk is higher in non-Hispanic Black individuals than in non-Hispanic White individuals. To evaluate progress toward reducing such disparities, tracking secular trends in racial disparities in dementia prevalence is essential. Objective: To examine whether relative racial disparities in dementia prevalence or incidence have changed in the US from 2000 to 2016. Design, Settings, and Participants: The Health and Retirement Study (HRS) is a nationally representative study of adults 50 years or older. New participants are recruited every 6 years, and study visits occur biennially. Approximately 17 000 to 22 000 respondents have been surveyed at each wave since 2000, achieving response rates of 81% to 89%. Data for this cohort study were obtained from non-Hispanic White and non-Hispanic Black participants aged 70 years and older from the 2000 to 2016 waves. For analyses of secular trends in racial disparities in dementia prevalence, each HRS wave was considered separately (range of participants meeting eligibility criteria in each wave, 6322-7579). For analyses of secular trends in racial disparities in dementia incidence, 7 subcohorts were created (range of participants meeting eligibility criteria in each subcohort, 5322-5961) following up people without dementia for 4 years from subcohort baseline visits in 2000, 2002, 2004, 2006, 2008, 2010, and 2012. Data were analyzed from October 2019 to August 2020. Exposures: Race based on self-response to closed-ended survey questions. Main Outcomes and Measures: Dementia status was determined using 3 algorithms with similar sensitivity and specificity across non-Hispanic White and Black participants. Disparities were characterized using ratio measures. Results: In this study, the mean age and percentage of male participants eligible for inclusion in analyses of racial disparities in dementia prevalence increased over time among non-Hispanic White participants (from 78.2 years and 40% in 2000 to 78.7 years and 44% in 2016) but remained steady in non-Hispanic Black participants during the same period (from 78.0 years and 37% in 2000 to 77.9 years and 38% in 2016). Prevalence ratios comparing Black and White participants ranged from approximately 1.5 to 1.9 across algorithms and years, whereas hazard ratios ranged from approximately 1.4 to 1.8. Although results suggest stable or declining dementia risk overall, there was no evidence suggesting change in relative racial disparities in dementia prevalence or incidence during follow-up. Conclusions and Relevance: This study did not find evidence to suggest that the ratio of dementia risk across Black and White individuals changed in the US between 2000 and 2016. Additional efforts to identify and mitigate the source of these disparities is warranted.

Estimation of dementia prevalence at the local level in the United States.

INTRODUCTION: Ensuring adequate and equitable distribution of resources to support persons living with dementia relies on understanding the burden and distribution of dementia in a population. Our goal was to develop an approach to estimate dementia prevalence at the local level in the United States using publicly available data. METHODS: Our approach combines publicly available data on dementia prevalence and demographic data from the US Census to estimate dementia prevalence. We illustrate this approach by estimating dementia prevalence in persons aged 65 and older in Philadelphia, PA; Chicago, IL; and Atlanta, GA. RESULTS: Overall, we estimate the prevalence of dementia among those 65 and older to be 11.9% in Philadelphia, 11.8% Chicago, and 12.3% in Atlanta. Estimates across Philadelphia localities vary from 9.3% to 15.9%. DISCUSSION: Our approach provides a cost-effective method to generate estimates of dementia prevalence at the local level. HIGHLIGHTS: Brain health needs assessments require understanding of local dementia prevalence.Our approach can be used to estimate dementia prevalence in individual communities.This information can inform decisions about distribution of resources.

Implications of the Use of Algorithmic Diagnoses or Medicare Claims to Ascertain Dementia.

INTRODUCTION: Formal dementia ascertainment with research criteria is resource-intensive, prompting the growing use of alternative approaches. Our objective was to illustrate the potential bias and implications for study conclusions introduced through the use of alternate dementia ascertainment approaches. METHODS: We compared dementia prevalence and risk factor associations obtained using criterion-standard dementia diagnoses to those obtained using algorithmic or Medicare-based dementia ascertainment in participants of the baseline visit of the Aging, Demographics, and Memory Study (ADAMS), a Health and Retirement Study (HRS) sub-study. RESULTS: Estimates of dementia prevalence derived using algorithmic or Medicare-based ascertainment differ substantially from those obtained using criterion-standard ascertainment. Use of algorithmic or Medicare-based dementia ascertainment can, but does not always, lead to risk factor associations that substantially differ from those obtained using criterion-standard ascertainment. DISCUSSION/CONCLUSIONS: Absolute estimates of dementia prevalence should rely on samples with formal dementia ascertainment. The use of multiple algorithms is recommended for risk factor studies when formal dementia ascertainment is not available.

The association between midlife lipid levels and late-life brain amyloid deposition.

Elevated low-density lipoprotein cholesterol and total cholesterol in midlife and decline in total cholesterol from mid- to late-life are associated with incident dementia. Whether brain amyloid deposition mediates this relationship is unclear. We explored the association between midlife blood lipid levels and mid- to late-life change in lipid levels with brain amyloid deposition assessed using florbetapir PET scans in a biracial sample of 325 nondemented participants of the Atherosclerosis Risk in Communities-PET Amyloid Imaging study. Midlife total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides were not significantly associated with late-life amyloid burden after adjusting for covariates. Associations between changes in lipids and late-life amyloid deposition were similarly null. Lipids may contribute to dementia risk through alternate mechanisms.

Association of traumatic brain injury with dementia and memory decline in older adults in the United States.

INTRODUCTION: To examine associations of history of traumatic brain injuries (TBIs) with loss of consciousness (LOC) with dementia incidence and memory decline. METHODS: We studied 2718 participants from the 1992 enrollment cohort of the Health and Retirement Study (HRS) aged 65 years or older in 2000. History of TBI with LOC was self-reported in 1992. Dementia was assessed using four algorithms established in HRS. Participants were followed from 2000 to 2014 with repeated measures of dementia and memory performance. Cox models and linear mixed-effects models were used. RESULTS: In 1992, 11.9% of the participants reported a history of TBI with LOC. In fully adjusted models for all four algorithms, participants with a history of TBI with LOC had no statistically significant difference in dementia incidence nor in memory decline, compared to participants without TBI history. DISCUSSION: Our study did not find evidence of a long-term association between history of TBI with LOC (of unknown frequency and severity) and dementia incidence or memory decline.

Choosing between medical management and liver transplant in urea cycle disorders: A conceptual framework for parental treatment decision-making in rare disease.

Urea cycle disorders (UCD) are rare inherited metabolic disorders caused by deficiencies of enzymes and transporters required to convert neurotoxic ammonia into urea. These deficiencies cause elevated blood ammonia, which if untreated may result in death, but even with optimal medical management, often results in recurrent brain damage. There are two major treatments for UCD: medical management or liver transplantation. Both are associated with mortality and morbidity but the evidence comparing outcomes is sparse. Thus, families face a dilemma: should their child be managed medically, or should they undergo a liver transplant? To (a) describe the factors that contribute to treatment choice among parents of children diagnosed with UCD and to (b) organise these factors into a conceptual framework that reflects how these issues interrelate to shape the decision-making experience of this population. Utilising grounded theory, qualitative data were collected through semi-structured interviews with parents (N = 35) and providers (N = 26) of children diagnosed with UCD and parent focus groups (N = 19). Thematic content analysis and selective and axial coding were applied. The framework highlights the life-cycle catalysts that frame families' personal perceptions of risks and benefits and describes the clinical, personal, social, and system factors that drive treatment choice including disease severity, stability, and burden, independence, peer experiences, and cost, coverage and access to quality care. Findings equip providers with evidence upon which to prepare for productive patient interactions about treatment options. They also provide a foundation for the development of patient-centred outcome measures to better evaluate effectiveness of treatments in this population.

Development of Algorithmic Dementia Ascertainment for Racial/Ethnic Disparities Research in the US Health and Retirement Study.

BACKGROUND: Disparities research in dementia is limited by lack of large, diverse, and representative samples with systematic dementia ascertainment. Algorithmic diagnosis of dementia offers a cost-effective alternate approach. Prior work in the nationally representative Health and Retirement Study has demonstrated that existing algorithms are ill-suited for racial/ethnic disparities work given differences in sensitivity and specificity by race/ethnicity. METHODS: We implemented traditional and machine learning methods to identify an improved algorithm that: (1) had ≤5 percentage point difference in sensitivity and specificity across racial/ethnic groups; (2) achieved ≥80% overall accuracy across racial/ethnic groups; and (3) achieved ≥75% sensitivity and ≥90% specificity overall. Final recommendations were based on robustness, accuracy of estimated race/ethnicity-specific prevalence and prevalence ratios compared to those using in-person diagnoses, and ease of use. RESULTS: We identified six algorithms that met our prespecified criteria. Our three recommended algorithms achieved ≤3 percentage point difference in sensitivity and ≤5 percentage point difference in specificity across racial/ethnic groups, as well as 77%-83% sensitivity, 92%-94% specificity, and 90%-92% accuracy overall in analyses designed to emulate out-of-sample performance. Pairwise prevalence ratios between non-Hispanic whites, non-Hispanic blacks, and Hispanics estimated by application of these algorithms are within 1%-10% of prevalence ratios estimated based on in-person diagnoses. CONCLUSIONS: We believe these algorithms will be of immense value to dementia researchers interested in racial/ethnic disparities. Our process can be replicated to allow minimally biasing algorithmic classification of dementia for other purposes.

Self-Reported Hearing Loss and Nonfatal Fall-Related Injury in a Nationally Representative Sample.

BACKGROUND/OBJECTIVE: To evaluate the relationship between self-reported hearing loss and nonfatal fall-related injury in a nationally representative sample of community-dwelling adults living in the United States. DESIGN: Cross-sectional analysis of national survey data. SETTING: National Health Interview Survey (2016). PARTICIPANTS: A total of 30 994 community-dwelling adults in the United States, aged 18 years and older. MEASUREMENTS: We evaluated the association between self-reported hearing loss and nonfatal injury resulting from a fall in the previous 3 months. We used multivariate logistic regression to calculate adjusted odds ratios (ORs) and evaluated effect measure modification by age. RESULTS: The odds of nonfatal fall-related injury were 1.60 times higher among respondents with hearing loss compared to respondents without hearing loss (95% confidence interval [CI] = 1.20-2.12; P = .0012). Results were unchanged when adjusting for demographics (OR = 1.59; 95% CI = 1.18-2.15; P = .002). After adjustment for cardiovascular risk factors, cardiovascular disease, visual impairment, and limitation caused by nervous system/sensory organ conditions and depression, anxiety, or another emotional problem, the OR fell to 1.27 (95% CI = 0.92-1.74; P = .14). In the fully adjusted model, including adjustment for vestibular vertigo, there was little support to link hearing loss and fall-related injury (OR = 1.16; 95% CI = 0.84-1.60; P = .36). Effect modification by age was not observed. CONCLUSIONS: Self-reported hearing loss may be a clinically useful indicator of increased fall risk, but treatment for hearing loss is unlikely to mitigate this risk, given that there is no independent association between self-reported hearing loss and nonfatal falls after accounting for vestibular function and other potential confounders.

Racial disparities and temporal trends in dementia misdiagnosis risk in the United States.

INTRODUCTION: Systematic disparities in misdiagnosis of dementia across racial/ethnic groups have implications for health disparities. We compared the risk of dementia under- and overdiagnosis in clinical settings across racial/ethnic groups from 2000 to 2010. METHODS: We linked fee-for-service Medicare claims to participants aged ≥70 from the nationally representative Health and Retirement Study. We classified dementia status using an algorithm with similar sensitivity and specificity across racial/ethnic groups and assigned clinical dementia diagnosis status using ICD-9-CM codes from Medicare claims. Multinomial logit models were used to estimate relative risks of clinical under- and overdiagnosis between groups and over time. RESULTS: Non-Hispanic blacks had roughly double the risk of underdiagnosis as non-Hispanic whites. While primary analyses suggested a shrinking disparity over time, this was not robust to sensitivity analyses or adjustment for covariates. Risk of overdiagnosis increased over time in both groups. DISCUSSION: Our results suggest that efforts to reduce racial disparities in underdiagnosis are warranted.

Comparison of Methods for Algorithmic Classification of Dementia Status in the Health and Retirement Study.

BACKGROUND: Dementia ascertainment is time-consuming and costly. Several algorithms use existing data from the US-representative Health and Retirement Study (HRS) to algorithmically identify dementia. However, relative performance of these algorithms remains unknown. METHODS: We compared performance across five algorithms (Herzog-Wallace, Langa-Kabeto-Weir, Crimmins, Hurd, Wu) overall and within sociodemographic subgroups in participants in HRS and Wave A of the Aging, Demographics, and Memory Study (ADAMS, 2000-2002), an HRS substudy including in-person dementia ascertainment. We then compared algorithmic performance in an internal (time-split) validation dataset including participants of HRS and ADAMS Waves B, C, and/or D (2002-2009). RESULTS: In the unweighted training data, sensitivity ranged from 53% to 90%, specificity ranged from 79% to 97%, and overall accuracy ranged from 81% to 87%. Though sensitivity was lower in the unweighted validation data (range: 18%-62%), overall accuracy was similar (range: 79%-88%) due to higher specificities (range: 82%-98%). In analyses weighted to represent the age-eligible US population, accuracy ranged from 91% to 94% in the training data and 87% to 94% in the validation data. Using a 0.5 probability cutoff, Crimmins maximized sensitivity, Herzog-Wallace maximized specificity, and Wu and Hurd maximized accuracy. Accuracy was higher among younger, highly-educated, and non-Hispanic white participants versus their complements in both weighted and unweighted analyses. CONCLUSION: Algorithmic diagnoses provide a cost-effective way to conduct dementia research. However, naïve use of existing algorithms in disparities or risk factor research may induce nonconservative bias. Algorithms with more comparable performance across relevant subgroups are needed.