Cognitive differences across ethnoracial category, socioeconomic status across the Alzheimer's disease spectrum: Can an ability discrepancy score level the playing field?

An ability discrepancy (crystallized minus fluid abilities) might be a personally relevant cognitive marker of risk for Alzheimer's disease (AD) and might help reduce measurement bias often present in traditional measures of cognition. In a large national sample of adults aged 60-104 years (N = 14,257), we investigated whether the intersectionality of group characteristics previously shown to pose a risk for AD including ethnoracial category, socioeconomic status, and sex (a) differed in ability discrepancy compared to traditional neuropsychological tests and (b) moderated the relationship between an ability discrepancy and AD symptom severity. In cognitively normal older adults, results indicated that across each decade, fluid and memory composite scores generally exhibited large group differences with sex, education, and ethnoracial category. In contrast, the ability discrepancy score showed much smaller group differences, thus removing much of the biases inherent in the tests. Women with higher education differed in discrepancy performance from other groups, suggesting a subgroup in which this score might reduce bias to a lesser extent. Importantly, a greater ability discrepancy was associated with greater AD symptom severity across the AD continuum. Subgroup analyses suggest that this relationship holds for all groups except for some subgroups of Hispanic Americans. These findings suggest that an ability discrepancy measure might be a better indicator of baseline cognition than traditional measures that show more egregious measurement bias across diverse groups of people.

Association Between Executive Dysfunction and Instrumental Activities of Daily Living: Racial and Ethnic Differences Among Community-Dwelling Older Adults in the Southeastern US.

OBJECTIVE: Examining cultural differences in assessment of cognitive/functional disability among older Americans is needed. This analysis examined associations between day-to-day function, measured by activities of daily living (ADL), and cognition, measured by CLOX scores, among older African American (AA) and non-Hispanic White (nHW) community-dwelling women and men. METHODS: Design- Cross-sectional. SETTING: Homes of community-dwelling older adults. Participants- 893 Medicare beneficiaries >65 living in west-central Alabama, without diagnoses of dementia, who were participants in the University of Alabama at Birmingham (UAB) Study of Aging, and who had complete data. Measurements- Physical function was assessed by self-reported ADL difficulty; cognitive function by CLOX, a clock drawing-task. Multivariable, linear regression models were used to examine associations within race/sex specific groups. RESULTS: After controlling for socio-demographic factors and comorbidities, CLOX1 scores were inversely and significantly correlated with ADL for AA men (ß = -0.205, P = 0.003). CLOX2 scores were similarly associated with ADL and IADL for the total group (ß = -0.118, P = 0.001, and ß = -0.180, P < 0.001, respectively); for ADL, significant associations were seen for AA men and nHW women (ß = -0.203, P = 0.004, and ß = -0.139, P = 0.02, respectively) and, for IADL, in AA women and men (ß = -0.156, P = 0.03, and ß = -0.24, P < 0.001, respectively). CONCLUSION: While African American women reported the highest difficulty with ADLs and IADLs among all race/sex groups, CLOX1 scores were correlated with ADL for AA men only. CLOX1 may have limitations to identify functional disability for older AA women. [Word Count = 234].

Racial Disparity in Cerebrospinal Fluid Amyloid and Tau Biomarkers and Associated Cutoffs for Mild Cognitive Impairment.

Importance: Prior evidence suggests that racial differences exist in tau biomarkers in mild cognitive impairment (MCI) and Alzheimer disease (AD). Whether this reported disparity is associated with a differential level of neurodegeneration and disease stage or with underlying mechanisms separate from amyloid or tau is unclear. Objectives: To compare cerebrospinal fluid (CSF) biomarkers in African American and white individuals with normal cognition and MCI, to estimate race-based cutoffs for these biomarkers that maximize diagnostic discrimination between normal cognition and MCI, and to study the association of demographic characteristics, cognitive performance, and common vascular risk factors with these differences. Design, Setting, and Participants: This case-control study conducted from March 1, 2016, through January 31, 2019, included participants in the Brain Stress Hypertension and Aging Research Program cohort undergoing baseline assessment. Participants were 50 years or older and recruited from the Atlanta, Georgia, area. Exposures: Self-reported race and cognitive status categorized using modified Petersen criteria and clinical consensus diagnosis. Main Outcomes and Measures: Levels of ß-amyloid 1-42 (Aß1-42), tau, and phosphorylated tau 181 (pTau181), the ratio of tau or pTau181 to Aß1-42, and hippocampal volume on magnetic resonance imaging of the brain. Results: Data from 362 study participants were analyzed (mean [SD] age, 65.6 [7.9] years), of whom 152 (42.0%) were African American, 230 (63.5%) were women, and 189 (52.2%) had MCI. After adjustment for demographic characteristics and cognitive performance, lower mean (SE) levels were observed in African American vs white individuals with MCI for tau (52.40 [5.90] vs 78.98 [5.02] pg/mL; P = .001) and pTau181 (15.42 [2.06] vs 25.24 [1.75] pg/mL; P = .001) and a lower pTau181 to Aß1-42 ratio (0.07 [0.02] vs 0.14 [0.01]; P = .003). There were no racial differences in the normal cognition group or in hippocampal volumes in the MCI group. Cutoffs for CSF biomarkers were higher for Aß1-42 in African American relative to white individuals (208 [95% CI, 126-321] vs 197 [95% CI, 183-245] pg/mL) and lower for tau (51 [95% CI, 31-59] vs 59 [95% CI, 56-92] pg/mL) and pTau181 (12 [95% CI, 12-19] vs 20 [95% CI, 12-27] pg/mL) levels. Cutoffs for the pTau181 to Aß1-42 ratio were 0.05 (95% CI, 0.03-0.12) for African American participants and 0.05 (95% CI, 0.05-0.13) for white participants. Conclusions and Relevance: This study found that African American individuals had lower levels of tau-based biomarkers that were not likely explained by the degree of disease stage or neurodegeneration reflected by hippocampal volumes. This study suggests that race is an important factor when interpreting CSF biomarkers, especially in the clinical diagnosis of prodromal AD. It appears that using the pTau181 to Aß1-42 ratio may ameliorate these differences.

To what extent do geriatricians document the most bothersome symptoms of patients with advanced dementia?

OBJECTIVES: To assess whether geriatricians documented the bothersome symptoms of patients with advanced dementia, proxy reports of the most-bothersome symptoms affecting those patients (as elicited in research interviews) were compared with what geriatricians who had seen those patients in a proximate clinic visit documented in the medical record. DESIGN: Retrospective chart review. SETTING: Outpatient geriatrics clinic at the University of Chicago. PARTICIPANTS: Fifty-seven pairs of patients with dementia (Functional Assessment Staging Tool stage 6 or 7) and their proxies. MEASUREMENTS: Clinic notes were reviewed for documentation of patients' bothersome symptoms that proxies reported during research interviews. Proxy reports had been recorded in the previously established Palliative Excellence in Alzheimer Care Efforts database. RESULTS: The most-bothersome symptom was documented at least once in 84.2% (48/57) of clinic notes. The second-most-bothersome symptom was documented in 70.3% (26/37) of clinic notes. Most symptoms were documented in the Assessment and Plan section of the note. CONCLUSION: Geriatricians identified and documented the vast majority of bothersome symptoms, as reported by proxies, of patients with moderate to severe dementia.

Race and documentation of cognitive impairment in hospitalized older adults.

OBJECTIVES: To evaluate whether race influences agreement between screening results and documentation of cognitive impairment and delirium. DESIGN: Secondary data analysis. SETTING: An urban, public hospital and healthcare system. PARTICIPANTS: Hospitalized older adults aged 65 and older admitted to general inpatient medical services evaluated for cognitive impairment (n = 851) and evaluated for delirium (n = 424). MEASUREMENTS: Cognitive impairment and delirium were measured in each participant using the Short Portable Mental Status Questionnaire (SPMSQ) and the Confusion Assessment Method (CAM), respectively, as the reference identification method. Clinical documentation of cognitive impairment and delirium was defined according to the presence of International Classification of Diseases, Ninth Revision (ICD-9), codes from within 1 year before hospitalization through discharge for cognitive impairment or from hospital admission through discharge for delirium. RESULTS: Two hundred ninety-four participants (34%) had cognitive impairment based on SPMSQ performance, and 163 (38%) had delirium based on CAM results. One hundred seventy-one (20%) of those with cognitive impairment had an ICD-9 code for cognitive impairment, whereas 92 (22%) of those with delirium had an ICD-9 code for delirium. After considering age, sex, education, socioeconomic status, chronic comorbidity, and severity of acute illness, of those who screened positive on the SPMSQ, African Americans had a higher adjusted odds ratio (AOR) than non-African Americans for clinical documentation of cognitive impairment (AOR = 1.66, 95% confidence interval (CI) = 0.95-2.89), and of those who screened negative on the SPMSQ, African Americans had higher odds of clinical documentation of cognitive impairment (AOR = 2.10, 95% CI = 1.17-3.78) than non-African Americans. There were no differences in clinical documentation rates of delirium between African Americans and non-African Americans. CONCLUSION: Racial differences in coding for cognitive impairment may exist, resulting in higher documentation of cognitive impairment in African Americans screening positive or negative for cognitive impairment.

Racial and sex differences in associations between activities of daily living and cognition in community-dwelling older adults.

OBJECTIVES: To examine the association between function measured according to activities of daily living (ADLs), instrumental activ1ities of daily living (IADLs), and cognition assessed according to Mini-Mental State Examination (MMSE) scores of older African-American and non-Hispanic white community-dwelling men and women. DESIGN: Cross-sectional study assessing associations between self-reported ADL and IADL difficulty and MMSE scores for race- and sex-specific groups. SETTING: Homes of community-dwelling older adults. PARTICIPANTS: A random sample of 974 African-American and non-Hispanic white Medicare beneficiaries aged 65 and older living in west-central Alabama and participating in the University of Alabama at Birmingham Study of Aging, excluding those with reported diagnoses of dementia or with missing data. MEASUREMENTS: Function, based on self-reported difficulty in performing ADLs and IADLs, and cognition, using the MMSE. Multivariable linear regression models were used to test the association between function and cognition in race- and sex-specific groups after adjusting for covariates. RESULTS: Mini-Mental State Examination scores were modestly correlated with ADL and IADL difficulty in all four race- and sex-specific groups, with Pearson correlation coefficients ranging from −0.189 for non-Hispanic white women to −0.429 for African-American men. Correlations between MMSE and ADL or IADL difficulty in any of the race- and sex-specific groups were no longer significant after controlling for sociodemographic factors and comorbidities. CONCLUSION: Mini-Mental State Examination was not significantly associated with functional difficulty in older African-American and non-Hispanic white men and women after adjusting for sociodemographic factors and comorbidities, suggesting a mediating role in the relationship between cognition and function.