"Medical Journeys" is a set of clinical resources reviewed by doctors, meant for physicians and other healthcare professionals as well as the patients they serve. Each episode of this journey through a disease state contains both a physician guide and a downloadable/printable patient resource. "Medical Journeys" chart a path each step of the way for physicians and patients and provide continual resources and support, as the caregiver team navigates the course of a disease.
For decades, the common medical shorthand has been that if you have a young-to-middle-age white female patient of northern European ancestry with neurological symptoms, you should immediately suspect multiple sclerosis (MS).
That shorthand is not wrong, but it also doesn't capture the true complexity and prevalence of MS. In 2023, Mitchell T. Wallin, MD, MPH, of the University of Maryland School of Medicine in Baltimore, and colleagues published a cohort study in that used health insurance claims data to calculate MS prevalence in the U.S. based on race/ethnicity.
The study found an estimated prevalence of approximately 3 cases per 1,000 people in Black Americans compared with about 4 cases per 1,000 people in white Americans. "We found a much higher prevalence of multiple sclerosis in Black Americans than previously thought," the investigators said.
Other recent research has also focused on better understanding MS in Black Americans. In an interview with 番茄社区, Tirisham Gyang, MD, of Ohio State University Wexner Medical Center in Columbus, cited a 2022 retrospective of approximately 2.6 million members of Kaiser Permanente Southern California that set out to determine whether the prevalence of MS varies by race and ethnicity. Annette Langer-Gould, MD, PhD, of Los Angeles Medical Center, and colleagues concluded that, although age- and sex-standardized MS prevalence was higher in white patients than Black patients (237.7 vs 225.8 per 100,000), the difference was not statistically significant.
Gyang said the findings have sparked discussion among neurologists about whether the incidence of MS is increasing or whether it has just been underdiagnosed in Black patients. "I think underdiagnosis is part of the story, but doesn't explain the whole thing," she said.
"Some of the data suggest an increased incidence in MS in these minority populations," Gyang explained. "Many patients of color who have MS have told me their doctor told them they were very unlikely to have MS because of not being in the right demographic. That's concerning."
How MS Affects Black People
Whatever role underdiagnosis plays, it's clear that the sequelae of MS impacts Black patients especially hard. A 2022 by Annette Okai, MD, of the North Texas Institute of Neurology and Headache in Plano, and colleagues catalogued a concerning array of worse outcomes for Black patients, including:
- More severe disease at baseline
- Later diagnosis
- More retinal damage
- Earlier mortality
- Higher Expanded Disability Status Scale (EDSS) scores
- Worse and/or faster-progressing disability
- Possibly reduced effectiveness of disease-modifying therapy (DMT)
MS Severity and Progression
A 2004 retrospective by Bruce A.C. Cree, MD, PhD, of the University of California San Francisco, and colleagues found that Black patients with MS may have more severe disease at baseline, with a significantly greater frequency of multifocal central nervous system involvement at initial clinical presentation.
Black patients are also more likely to have neurodegeneration, and loss of brain and retinal tissue, than white patients, as shown by MRI and optical coherence tomography. A 2018 found that Black patients with MS had greater annual atrophy of gray matter (−0.9% vs −0.5%), white matter (−0.7% vs −0.3%), and nuclear thalamic tissue (−1.5% vs −0.7%) compared with white patients with MS.
Similarly, Black patients' retinal nerve fiber layer showed higher atrophy rates than those of white patients (−1.1% vs −0.8%). The same was also true of annual atrophy of the ganglion cell inner plexiform layer (0.7% vs −0.4%).
As for mortality data, an of 16 years of information from the CDC's Data for Epidemiologic Research system also revealed a concerning trend, that Black patients in the 55- to 64-year-old age group had the highest mortality rates, while mortality for white patients peaked at ages 65-74. Additionally, Black patients with MS had the highest mortality rate in patients younger than age 55 compared with patients with MS in other minority groups.
Black Patients More Likely to Become Disabled
A 2006 retrospective found that Black patients with MS may also have higher EDSS scores than white patients at diagnosis (2.9 vs 1.8). This trend continued through ≥5-year follow-up, when Black patients scored an average of 5.6, compared with 4.1 for white patients.
The study by Cree and colleagues showing more severe baseline disease in Black patients also found they may have faster clinical progression and worse clinical outcomes than their white counterparts. Black patients, with a mean disease duration of 9.8 years, had a significantly shorter median time to needing a cane to ambulate (16 vs 22 years) and wheelchair dependency (30 vs 38 years.)
Black patients also had a 1.67-fold greater risk of requiring a cane for ambulation and a trend toward a shorter median conversion time to secondary progressive MS (18 vs 21 years) vs white patients, who had a mean disease duration of 11.4 years. The researchers said they attributed this partly to the fact that Black patients were on average more than 2 years older at diagnosis (age 33.7 vs 31.1).
Role of Social Determinants of Health
Of course, none of these findings exist in a vacuum. The social determinants of health -- the nonmedical factors that influence an individual's health, well-being, and quality of life -- also play an unquantifiable role in why Black patients with MS fare worse over time.
Gyang noted that patients of color and/or lower socioeconomic status may also have difficulties with access, including to:
- Neurologists who can provide specialized MS care
- Multidisciplinary care
- Physical or occupational therapy
- Mental health services
- Effective DMTs
"All these factors are going to affect that individual and have a macro effect on how disabled they become over time," Gyang said. "In MS, 'time is brain,' so the earlier and more aggressively we intervene, the better the outcomes over that patient's lifetime."
Are DMTs Less Effective for Black Patients?
Another perplexing issue in clinical care is whether DMTs are less effective in Black patients than in their white counterparts. In 2005, Cree and colleagues published an exploratory of the EVIDENCE clinical trial that examined the effectiveness of interferon beta-1a treatment in 36 Black patients with MS. The team found that Black patients had more exacerbations and were less likely to remain exacerbation-free. They also developed more new MS lesions on T2-weighted brain MRI at 48 weeks.
In the two decades since, numerous studies have tried to clarify whether DMTs are less effective in Black patients, but clear answers remain elusive.
Need for Greater Diversity in Clinical Trials/MS Registry
A large part of this continuing lack of clarity surrounding the effectiveness of DMTs relates to the fact that not enough Black patients have participated in clinical trials. The review by Okai and co-authors included a compilation of the numbers of Black participants in major MS clinical trials:
- AFFIRM: 1.1%, 10 of 942 patients -- natalizumab (Tysabri)
- SENTINEL: 3.3%, 39 of 1,171 patients -- natalizumab
- OPERA I/II: 4.3%, 72 of 1,656 patients -- ocrelizumab (Ocrevus)
- PREFERMS: 16.1%, 141 of 875 patients -- fingolimod (Gilenya)
- ESTEEM: 3.7%, 187 of 5,084 patients -- dimethyl fumarate (Tecfidera)
Subgroup analyses of patients from these pivotal trials suggest that these therapies provide good clinical and radiological benefits for Black patients, but the need for better representation in clinical trials remains urgent.
A relatively easy way to encourage your Black patients with MS to participate in clinical research is to introduce them to the , an online observational research study based at Providence St. Vincent Health in Portland, Oregon. Participation is easy, secure, and doesn't require any changes in care.
Read previous installments in this series:
Part 1: Early Diagnosis Can Mean Better Outcomes in Multiple Sclerosis
Part 2: How Does Multiple Sclerosis Start?
Part 3: The Deep and Multidimensional Connection Between Multiple Sclerosis and Depression
Part 4: Case Study: Sudden Blurred Vision in a Young Woman
Part 5: Early Aggressive Treatment May Work Best in Newly Diagnosed Multiple Sclerosis
Part 6: How Progressive Multiple Sclerosis Differs From Relapsing-Remitting MS
Part 7: The Challenge of Cognitive Changes in Multiple Sclerosis
Part 8: Case Study: What Is the Cause of This Right-Sided Numbness, Headache, and Blurred Vision?