Study reveals racial disparities in Huntington’s disease diagnoses

New research led by UCLA Health revealed that Black patients with Huntington’s disease in the U.S. and Canada received their diagnoses, on average, one year later compared to White patients after symptoms first appear.

Huntington’s disease is a rare, incurable genetic disease that causes a gradual death of nerve cells, resulting in a variety of symptoms affecting movement, emotions and cognition. About 41,000 Americans have the disease and 200,000 are at risk of inheriting it, according to the Huntington’s Disease Society of America. Children of a parent with Huntington’s disease has a 50% of getting it.

The study, published in the journal Neurology: Clinical Practice, analyzed health data collected from nearly 5,000 Huntington’s disease patients from the U.S. and Canada.

Dr. Adys Mendizabal, lead author of the study and UCLA Health assistant professor of neurology, said early diagnosis is essential for allowing patients to access appropriate care and prepare for the significant life changes resulting from the neurodegenerative disease.

“The sooner people come into care, the more information they have and the more they can plan,” Mendizabal said. “Ultimately, we cannot yet change of the progression of the disease but we can definitely change the quality of life that people and their families experience while having the disease.”

While the data does not include specific information as to why Black patients receive a later diagnosis, Mendizabal said studies have documented racial and ethnic disparities in healthcare access to general neurologists and specialists for neurological care.

Delayed diagnoses also have implications in exacerbating underrepresentation of minority groups in clinical trials for treatments.

“We have a lot of clinical trials in Huntington’s that focus on disease modification, trying to prevent or slow down the onset of symptoms,” Mendizabal said. “But if you know that we have certain subgroups of patients that are experiencing delayed diagnoses or coming in with more severe disease, then they may not be eligible to be part of a clinical trial.”

The findings rely on the multicenter ENROLL-HD research platform. Led by the privately-funded CDHI Foundation, the platform is the world’s largest observational study of Huntington’s disease patients and provides publicly available health data for researchers.

UCLA Health used the data to investigate whether the time it takes to diagnose Huntington’s disease after symptoms first appear is influenced by factors such as race, socioeconomic status, initial symptoms, and family history awareness.

The main findings included:

• Black patients were diagnosed one year later than White individuals (4.6 years versus 3.7 years)
• No significant differences in diagnosis time among Latino, Asian and Native American patients compared to white patients, although this may be due to very small number of patients from these racial and ethnic groups
• The average time to diagnosis for all patients was 3.8 years
• Patients with no or unknown family history of the disease were diagnosed 1.6 to 2 years later than those with known family history
• Unemployed patients were diagnosed 1.3 years later than those with full-time jobs
• Patients with PhD/doctorate degrees were diagnosed 1.7 years later than those with a high school degree or GED
• Patients with psychiatric symptoms as their first sign of the disease were diagnosed a year later than those with motor symptoms.

Of the 4,717 patients included in this study, nearly 90% were White and only 2.3% were Black. Mendizabal said that given the barriers to healthcare access in the U.S., she suspects the true delays in diagnosis are likely underestimated in this study. The data used in the study is also only collected at Huntington’s Disease Centers of Excellence, which are mostly located in urban areas and affiliated with academic institutions, including UCLA, which may limit access for certain geographic areas.

To address limitations in the ENROLL-HD data, Mendizabal said further clinical data is needed to better understand barriers to healthcare access. She adds that there also needs to be better tracking of the quality of care and health outcomes from treatment among minority populations.

“In addition to reviewing clinical data, we also need qualitative studies to appropriately understand the experience of minoritized groups with Huntington’s disease both as they navigate the disease, as well as accessing care for a rare disease within our healthcare systems,” Mendizabal said. “Our findings serve as a starting point to create awareness and improve access to care for minoritized groups affected by rare neurological diseases.”

Article: Racial Disparities in Time to Huntington Disease Diagnosis in North America, Mendizabal et al., Volume 14 (5), 2024, ISSN ​​​​​​