Neuropathological and Clinical Correlates of Lewy Body Disease Survival by Race and Ethnicity in the National Alzheimer’s Coordinating Center

Abstract

Background: Survival and associated clinical and pathological characteristics in Lewy body disease (LBD)-related dementias are understudied. Available studies focus primarily on white non-Hispanic samples. Objective: We investigated demographic, clinical, and pathological correlates of survival by race and ethnicity in an autopsy-confirmed cohort of LBD cases. Methods: Using National Alzheimer’s Coordinating Center data, we selected participants who self-identified as Black, Hispanic, or white who had neuropathological assessments showing transitional or diffuse LBD pathology. We used Kruskal-Wallis and Pearson χ2 analyses to investigate group differences in demographic and presenting clinical and pathological characteristics. We used linear regressions to identify predictors of survival with sex, age at symptom onset, education, ethnoracial status, LBD pathology type, and Braak tangle stage included in the model. Results: Data from 1,441 white, 60 Black, and 54 Hispanic participants were available for analysis. Hispanics were more likely to have transitional LBD pathology and had a longer survival than white and Black participants. After controlling for demographic and pathological variables, length of survival did not differ between Hispanics and Black or white participants. Additional key findings demonstrated discrepancies between clinical diagnoses received at last visit and pathological findings, particularly among Black participants. Conclusion: LBD survival differences by race and ethnicity can be accounted for by LBD pathology type and co-occurring Alzheimer’s disease pathology. The discrepancies between clinical diagnoses and pathological findings raise concern that dementia with Lewy bodies is underdiagnosed in NACC, especially for Black older adults.

On gaps of clinical diagnosis of dementia subtypes: A study of Alzheimer’s disease and Lewy body disease

“…This finding confirms our result that patients with LBD autopsy have a lower diagnosis accuracy compared with other groups even at later dementia stages. The results from Kurasz et al (2022) demonstrate that Black/African American participants were less likely to receive LBD as the clinical primary diagnosis despite having a higher frequency of diffuse LBD pathology than their White and Hispanic counterparts. Another study ( Chatterjee et al, 2021 ) noted that autopsy-confirmed AD+LBD had a premortem syndrome with higher prevalence of memory issues and less classical LBD symptoms compared to pure LBD pathology.…”

“…Yet, AD+LBD presented with more parkinsonism, visual hallucinations, RBD and cognitive fluctuations than pure AD. Many of these studies ( Surendranathan et al, 2020 ; Chatterjee et al, 2021 ; Kurasz et al, 2022 ) confirm that autonomic dysfunction (urinary incontinence, orthostatic hypotension) and repeated falls could be a significant diagnostic clue for LBD pathology (pure or mixed).…”

Under-Diagnosis of Dementia with Lewy Bodies in Individuals Racialized as Black: Hypotheses Regarding Potential Contributors

“…It is also possible that clinicians are predisposed to give AD dementia diagnoses to Black individuals based on the research showing high prevalence in this population. These hypotheses are supported by NACC research showing that 88% of Black participants with Lewy body pathology (65% diffuse, 35% transitional) were assigned a primary etiologic cause of AD clinically, with only 5% assigned a secondary diagnosis of suspected Lewy body disease despite 70% having sufficient Lewy body pathology to predict an intermediate-high likelihood of a clinical DLB presentation [ 5 ]. Unrecognized Lewy body disease could also potentially help explain lower proportions of amyloid PET positivity among Black adults with MCI or dementia [ 21 ].…”

“…In NACC, there were no differences in the frequency of hallucinations or delusions between racial-ethnic groups in individuals clinically diagnosed with cognitive impairment due to Lewy body disease [ 22 ]. In individuals with Lewy body disease pathology, there were also no statistically significant differences in the frequency of visual hallucinations reported between racial-ethnic groups [ 5 ]. These findings are in contrast to a NACC study using all-cause dementia, where the odds of experiencing hallucinations and delusions were over double among Black participants with dementia (versus White) and other neuropsychiatric symptoms were also more common in Black participants [ 23 ].…”

“…The prevalence of Lewy body dementia codes was 5.5% in White non-Hispanic adults and 6.1% in Hispanic adults [ 4 ]. Multiple studies using the U.S.-based National Alzheimer Coordinating Center (NACC) database identified that fewer Black participants with pathologic Lewy body disease had a clinical suspicion for Lewy body dementia in life compared to White or Hispanic participants [ 5, 6 ]. Over 96% of participants in clinical trials for Lewy body dementia identify as White [ 7 ].…”