Characterizing retinal structure injury in African-Americans with multiple sclerosis

Multiple Sclerosis in Black and Hispanic Populations: Serving the Underserved

Multiple sclerosis has historically been characterized as a disease that affects young women of European ancestry, but recent studies indicate that the incidence and prevalence of the disease is much higher in Black and Hispanic populations than previously recognized. There is evidence that there is a more severe disease course in these populations. , but the intersection of genetic underpinnings and social determinants of health (SDOH) is poorly understood due to the lack of diversity in clinical research. Improving health disparities will involve multiple stakeholders in efforts to improve SDOH and raise awareness about research involvement and the importance of developing personalized health care plans to combat this disease.

Advancing Care and Outcomes for African American Patients With Multiple Sclerosis

Multiple sclerosis (MS) has historically been underdiagnosed and undertreated among African Americans. Recent evidence suggests that African Americans with MS have a different clinical presentation, increased disease incidence and burden, and worse long-term outcomes vs their White counterparts. Due to limited data available for African Americans in MS clinical trials, it is difficult to make informed, generalizable conclusions about the natural history, prognosis, and therapeutic response in this population. In this narrative review, we highlight the nature and magnitude of the health disparities experienced by African Americans with MS and underscore the pressing need to increase knowledge about and understanding of MS disease manifestations in this group. In addition, we describe the mission and objectives of the recently established National African Americans with Multiple Sclerosis Registry, which is intended to be a platform to advance the care of African Americans with MS and address health disparities they may experience.

Effect of Obesity on Retinal Integrity in African Americans and Caucasian Americans With Relapsing Multiple Sclerosis

Objective: To study the effect of obesity on retinal structures in African Americans (AAs) and Caucasian Americans (CAs) with relapsing-remitting multiple sclerosis (RRMS).

Methodology: About 136 patients with RRMS without history of optic neuritis were divided into two groups, based on body mass index (BMI): 67 obese (40 AA, 27 CA, mean BMI ± SD: 36.7 ± 5.8), and 69 non-obese (23 AA, 46 CA, mean BMI ± SD: 24.0 ± 3.1). The peripapillary retinal nerve fiber layer (pRNFL) thickness was quantified by optical coherence tomography (OCT) and was segmented into quadrant thickness: superior (S), inferior (I), temporal (T), and nasal (N). Papillomacular bundle (PMB) thickness, retinal nerve fiber layer (RNFL), ganglion cell + inner plexiform layer (GCIPL), inner nuclear (INL), outer plexiform (OPL), outer nuclear (ONL), and total macular (TMV) volumes were obtained.

Results: Obesity was associated with lower T thickness (58.54 ± 15.2 vs. 61.9 12.4, p = 0.044), higher INL (0.98 ± 0.07 vs. 0.96 ± 0.06, p = 0.034), and lower RNFL (0.77 ± 0.14 vs. 0.82 ± 0.12, p = 0.009) volumes. Obese AA had significantly thinner T (58.54 ± 15.19 vs. 61.91 ± 12.39, p = 0.033), N (68.94 ± 2.7 vs. 77.94 ± 3.3, p = 0.044), and TMV (8.15 ± 0.07 vs. 8.52 ± 0.09, p = 0.003), RNFL (0.74 ± 0.02 vs. 0.82 ± 0.02, p = 0.013), OPL (0.76 ± 0.01 vs. 0.79 ± 0.1, p = 0.050), ONL (1.68 ± 0.031 vs. 1.79 ± 0.038, p = 0.026), and GCIPL (1.78 ± 0.04 vs. 1.9 ± 0.05, p = 0.038) compared to obese CA. Among patients with non-obesity, the ONL was significantly lower in AA (1.78 ± 0.04 vs. 1.9 ± 0.05, p < 0.001).

Conclusions: Obesity is associated with retinal structure abnormalities in patients with RRMS. Its impact might be more prominent in AA than CA. Large longitudinal studies are needed to validate our findings.

Cortical surface thickness, subcortical volumes and disability between races in relapsing-remitting multiple sclerosis

BACKGROUND

The interplay between cortical surface thickness (CTh), subcortical volumes (SCV) and disability in patients with relapsing remitting multiple sclerosis (RRMS) is still not clear.

OBJECTIVE

To examine the relationship between CTh, SCV, and disability and investigate differences in CTh, SCV and disability between African Americans (AA) and Caucasian Americans (CA).

METHODS

Sixty-five RRMS (33AA, 32 CA) participants underwent Expanded Disability Status Scale and Multiple Sclerosis Functional Composite (MSFC) assessments, including timed 25-foot walk (T25FW), nine-hole peg test (9HPT) on dominant (D) and non-dominant hand (ND) and paced auditory serial addition test (PASAT-3). Symbol digit modalities test (SDMT) was also administered. All participants underwent 3T brain MRI. CTh was measured in the Frontal (FA), Parietal (PA), Temporal (TA), Occipital (OA), Cingulate (CA), and Global (GA) cortical surface areas (CSA). SCV measurements included Thalamus (TV), Caudate (CV), Putamen (PV), Pallidum (PaV), Hippocampus (HV), Amygdala (AV), Accumbens (AcV), Brain Stem (BSV), and Deep Gray Matter Total Volume (DGMTV). A general linear model with multivariate analysis (MANOVA) was used to determine the differences between the two cohorts (SPSS vs 25). Spearman rank correlation analysis was performed to investigate the relationship between CTh and MSFC.

RESULTS

AA have significantly decreased FA, PA, TA, GA CTh compared to CA (p = 0.004, p = 0.018, p = 0.013, p = 0.015, respectively). SCV measurements were not significantly different. Only in CA, the MSFC measures correlate significantly with regional CSA CTh. In both races and in the entire group, T25FW correlates with TV, PV, AV, AcV and DGMTV (p < 0.05). Only in AA and the entire cohort, PASAT-3 correlates with TV and AcV(p = 0.041, p = 0.006, p = 0.006, p = 0.000 respectively).

CONCLUSIONS

Differences in CSA CTh reinforce the different disease pathobiology between AA and CA. Regional CTh may represent a useful biomarker related to multi-domain disability only in CA, while in AA DGM injury might be a more important contributor to disability. Longitudinal, large-scale studies are warranted to confirm our findings.

Efficacy and safety of ocrelizumab vs interferon beta-1a in participants of African descent with relapsing multiple sclerosis in the Phase III OPERA I and OPERA II studies

BACKGROUND

People of African descent with multiple sclerosis (MS) appear to have a more severe disease course and may have an attenuated response to some medications compared with people of European descent.

METHODS

This is a post hoc subgroup analysis of participants of African descent with relapsing forms of MS who were enrolled in the Phase III OPERA I or OPERA II clinical trials and treated with ocrelizumab (OCR) 600 mg every 6 months or interferon beta-1a (IFN β-1a) 44 μg 3 times per week.

RESULTS

Among the 1,656 participants enrolled in OPERA I and II, 72 (4.3%) were of African descent (OCR, 40; IFN β-1a, 32). A trend for reduction in annualized relapse rate (ARR) was observed in participants of African descent, with an ≈50% reduction with OCR vs IFN β-1a. The relative rate of the mean number of gadolinium-enhancing lesions on magnetic resonance imaging (MRI) was 0.04 (95% CI, 0.01-0.22; p=0.001) in participants of African descent treated with OCR compared with IFN β-1a. Similarly, the relative rate of the number of new or enlarging T2 lesions on MRI was 0.14 (95% CI, 0.06-0.32; p<0.001). In participants of African descent, those treated with OCR were 2.61 times more likely than those who received IFN β-1a to be classified as having no evidence of disease activity (95% CI, 1.24-5.49; p=0.003) and 4.17 times more likely to be classified as having no evidence of disease activity or progression (95% CI, 1.27-13.65; p=0.006). African-descent participants tended to have a greater radiographic burden of disease at baseline, develop more brain lesions when treated with IFN β-1a, and be at greater risk of disability progression than non-African-descent participants. Participants of African descent experienced slightly more adverse events, serious adverse events, and hypersensitivity reactions than non-African-descent participants.

CONCLUSION

In this small sample of participants of African descent with relapsing MS from the OPERA studies, OCR demonstrated treatment benefits in clinical, MRI, and composite efficacy outcomes vs IFN β-1a, consistent with what was observed in the complete OPERA intention-to-treat cohorts.

Brain and retinal atrophy in African-Americans versus Caucasian-Americans with multiple sclerosis: a longitudinal study

On average, African Americans with multiple sclerosis demonstrate higher inflammatory disease activity, faster disability accumulation, greater visual dysfunction, more pronounced brain tissue damage and higher lesion volume loads compared to Caucasian Americans with multiple sclerosis. Neurodegeneration is an important component of multiple sclerosis, which in part accounts for the clinical heterogeneity of the disease. Brain atrophy appears to be widespread, although it is becoming increasingly recognized that regional substructure atrophy may be of greater clinical relevance. Patient race (within the limitations of self-identified ancestry) is regarded as an important contributing factor. However, there is a paucity of studies examining differences in neurodegeneration and brain substructure volumes over time in African Americans relative to Caucasian American patients. Optical coherence tomography is a non-invasive and reliable tool for measuring structural retinal changes. Recent studies support its utility for tracking neurodegeneration and disease progression in vivo in multiple sclerosis. Relative to Caucasian Americans, African American patients have been found to have greater retinal structural injury in the inner retinal layers. Increased thickness of the inner nuclear layer and the presence of microcystoid macular pathology at baseline predict clinical and radiological inflammatory activity, although whether race plays a role in these changes has not been investigated. Similarly, assessment of outer retinal changes according to race in multiple sclerosis remains incompletely characterized. Twenty-two African Americans and 60 matched Caucasian Americans with multiple sclerosis were evaluated with brain MRI, and 116 African Americans and 116 matched Caucasian Americans with multiple sclerosis were monitored with optical coherence tomography over a mean duration of 4.5 years. Mixed-effects linear regression models were used in statistical analyses. Grey matter (-0.9%/year versus -0.5%: P =0.02), white matter (-0.7%/year versus -0.3%: P =0.04) and nuclear thalamic (-1.5%/year versus -0.7%/year: P =0.02) atrophy rates were approximately twice as fast in African Americans. African Americans also exhibited higher proportions of microcystoid macular pathology (12.1% versus 0.9%, P =0.001). Retinal nerve fibre layer (-1.1% versus -0.8%: P =0.02) and ganglion cell+ inner plexiform layer (-0.7%/year versus -0.4%/year: P =0.01) atrophy rates were faster in African versus Caucasian Americans. African Americans on average exhibited more rapid neurodegeneration than Caucasian Americans and had significantly faster brain and retinal tissue loss. These results corroborate the more rapid clinical progression reported to occur, in general, in African Americans with multiple sclerosis and support the need for future studies involving African Americans in order to identify individual differences in treatment responses in multiple sclerosis.

Native ancestry is associated with optic neuritis and age of onset in hispanics with multiple sclerosis

Background and Objective

Hispanics with multiple sclerosis (MS) present younger and more often with optic neuritis (ON) as compared to Whites in the western United States. Regional differences related to Hispanic genetic admixture could be responsible. We investigated the association between global genetic ancestry and ON and age at onset of MS in Hispanics.

Methods

Data were obtained for 1033 self‐identified Hispanics with MS from four MS‐based registries from four academic institutions across the United States January 2016–April 2017. Multivariate regression models, utilizing genetic ancestry estimates for Native American (NA), African, and European ancestry, were used to assess the relationship between genetic ancestry and ON presentation and age of MS onset, defined as age at first symptom.

Results

Genetic ancestry and ON proportions varied by region where NA ancestry and ON proportions were highest among Hispanics in the southwestern United States (40% vs. 19% overall for NA and 38% vs. 25% overall for ON). A strong inverse correlation was observed between NA and European ancestry (r = −0.83). ON presentation was associated with younger age of onset (OR: 0.98; 95% CI: 0.96–0.99; P = 7.80 × 10⁻⁰³) and increased NA ancestry (OR: 2.35 for the highest versus the lowest quartile of NA ancestry; 95% CI: 1.35–4.10; P = 2.60 × 10⁻⁰³). Younger age of onset was found to be associated with a higher proportion NA (Beta: −5.58; P = 3.49 × 10⁻⁰²) and African ancestry (Beta: −10.07; P = 1.39 × 10⁻⁰³).

Interpretation

Ethnic differences associated with genetic admixture could influence clinical presentation in Hispanics with MS; underscoring the importance of considering genetic substructure in future clinical, genetic, and epigenetic studies in Hispanics.