In Huntington’s Disease, Exploring the Roles of Race, Ethnicity, and Education
—A study identified racial and ethnic disparities in Huntington’s disease, as well as differences based on levels of education of patients, finding that minority patients may be disproportionately affected.
Racial and ethnic minorities with neurological diseases often have more severe disease at the time of diagnosis than non-Hispanic Whites. This disparity and other Social and Structural Determinants of Health (SDOH) have not been well studied in patients with Huntington's disease (HD). The authors of a new study aimed to assess whether a relationship between race/ethnicity, selected SDOH, and HD severity exists at the time of diagnosis.1
This retrospective study recruited participants from the longitudinal, multicenter ENROLL-HD 2020 periodic dataset. This dataset includes patients with and without the HD mutation, the latter used as controls. A total of 21,116 patients were considered for inclusion. Patients with cytosine-adenine-guanine (CAG) repeats <36 or >70 and those not from the North American region (United States and Canada) were excluded from the primary analysis. This yielded a cohort of 4717 patients, the majority of whom were female (55.9%) and lived in a city (54.7%).1
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The mean age at study entry was 30.77 years, and the mean CAG repeat length was 43.5. While most of the cohort was unemployed at the time of enrollment in the study (58.7%), almost half had completed secondary or professional education (44.88%). Motor (55.5%) and psychiatric symptoms (19.8%) were the most common symptoms reported at HD onset. Of the participants that did not identify as non-Hispanic white, 3.35% (n=158) were Latino, 2.29% (n=108) were Black, 1.12% (n=53) were Native American, and 0.68% (n=32) were Asian.1
Symptom severity was measured by the Total Functional Capacity Score (TFC); the average TFC in this cohort was 10.22. Those who did not have an age recorded at diagnosis were excluded from the sensitivity analysis, yielding a cohort of 3130.1
Three sequential models were constructed to evaluate the relationship between SDOH and HD severity; the first was a simple linear regression of race/ethnicity and TFC score, the second included SDOH and biological variables in the first model, and the third was an analysis of variance (ANOVA) of interactions between race/ethnicity, education, and initial symptom presentation. The primary objective of the study was to test whether the selected racial and demographic variables were associated with the severity of HD at the time of study enrollment.1
Despite the small sample, Black participants were significantly more likely than non-Hispanic whites to have a higher level of disability at the time of study enrollment (P<.001). More CAG repeats and an initial presentation of psychiatric symptoms were significantly associated with a higher level of disability (both P<.001). Those with higher education or professional degrees (P<.001) and PhD/doctorate degrees (P=.005) presented with a significantly lower level of disability than those with less than a high school degree (P=.003). All minority groups were younger than non-Hispanic Whites both at the time of diagnosis and study enrollment.1
Corresponding author Adys Mendizabal, MD, MA, of the Department of Neurology, David Geffen School of Medicine, University of California in Los Angeles, CA, tells MedPage today that the study findings will hopefully result in better recognition and care for minority HD patients, “Our findings shed light on racial and ethnic disparities in HD and hopefully serve as a call to action for HD researchers, clinicians, and pharmaceutical companies to consider minoritized groups in HD research, include them in clinical trials, and improve community education and access to HD care and resources. Our findings hopefully encourage the HD and general neurology community to consider an HD diagnosis in Black and other minoritized patients who present with involuntary movement disorders such as chorea. Hopefully, early recognition and referral will allow communities of color to access HD clinical trials and HD care in earlier stages of the disease.”
To build on this study’s findings, Dr. Mendizabal says more robust data collection and clinical trial recruiting practices are needed, “We need additional studies independent of ENROLL-HD and to rely on clinical data from HDSA Centers of Excellence. ENROLL-HD is a research study that involves biosample data collection. Due to a long history of unethical experimentation, many minoritized groups in the US may choose not to participate in research studies involving biosample data collection. We also know that minoritized groups may be less likely to be asked to participate in research, even if they are interested. Most clinical research takes place in English with English-speaking staff. This limits the ability of patients with limited English proficiency, including many Latinos who primarily speak Spanish, to participate in clinical research.” Dr. Mendizabal adds that other types of data are needed to understand and mitigate disparities in HD care, “Studying healthcare disparities in HD based on clinical data may be a better way of evaluating the extent of disparities in HD care and outcomes. We also need to rely on qualitative data, including patient interviews, to understand the experience of Black and other minoritized patients with Huntington’s Disease. Understanding how these communities access HD care is pivotal in eliminating disparities and providing access to clinical research, such as ENROLL-HD, earlier in the disease process.”
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