Neuromyelitis optica spectrum disorder (NMOSD) appears to be associated with worse outcomes than myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), regardless of ethnicity, in the Latin American population, according to a recently published study in Multiple Sclerosis and Related Disorders.
Although there are different pathological mechanisms involved in NMOSD and MOGAD, the former being astrocytopathy and the latter oligodendrocytopathy, both diseases typically present with optic neuritis attacks and are characterized by subsequent relapses. Furthermore, the radiological characteristics of both entities are practically identical, making differential diagnosis difficult.
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Long-term treatment varies between the entities, as NMOSD requires immunomodulatory treatment to prevent relapses that lead to permanent disability, and the use of preventive immunotherapy in MOGAD remains controversial.
Although NMOSD is associated with more severe outcomes than MOGAD, the authors hypothesized that ethnicity could play a role as a prognostic factor in both entities. However, there are currently no studies comparing mixed ethnicities to other ethnicities.
“Thus, we aimed to compare clinical outcomes and prognostic features of patients with NMOSD and MOGAD presenting [optic neuritis] as a first attack, from different ethnic groups in [Latin America],” the authors wrote.
The retrospective study included 195 patients with NMOSD or MOGAD from 6 Latin American countries (Argentina, Chile, Brazil, Venezuela, Mexico, and Ecuador). Patients were classified into 3 different ethnic groups, namely individuals of European descent, individuals of mixed Native American and African descent, and individuals of mixed European and Amerindian ancestry. Neurologists recorded all relevant clinical data of the patients, including relapses, visual outcomes, and Expanded Disability Status Scale (EDSS) scores.
The authors then compared factors in NMOSD and MOGAD, with a special emphasis placed on disability measures.
The results revealed that patients with NMOSD had a higher rate of recurrence and were more likely to have severe visual disability and permanent motor disability than those with MOGAD. Rituximab use was also significantly more frequent among patients with NMOSD.
According to the statistical analysis, ethnicity appeared to have no significant impact on disease course or final outcome. On the other hand, older age and the simultaneous appearance of optic neuritis and myelitis appeared to be independent predictors of severe motor and visual disability.
“NMOSD was associated with poorer clinical outcomes than MOGAD. Ethnicity was not associated with prognostic factors in this large [Latin American] cohort,” the authors concluded.
Carnero Contentti E, López PA, Criniti J, et al. Clinical outcomes and prognostic factors in patients with optic neuritis related to NMOSD and MOGAD in distinct ethnic groups from Latin America. Mult Scler Relat Disord. Published online March 7, 2023 doi:10.1016/j.msard.2023.104611