Phenotype and prognosis in African-Americans with multiple sclerosis: A retrospective chart review

Context: There is an emerging body of literature regarding multiple sclerosis (MS) in African-Americans (AA) that suggests more rapid progression and a worse prognosis in this group. A phenotype of opticospinal MS has been proposed by some publications. Objective: To determine whether AA with MS have a different clinical phenotype, different distribution of clinical subtypes, and/or different levels of disability than Caucasians (CA) with MS. Specifically, is the disability attributable to severe cerebellar disease, which limits ambulation and function? Design: Retrospective chart analyses of a patient cohort from an academic MS center. Patients: A total of 86 AA were identified with MS, 79 were followed for ≥5 years. The control group consisted of 80 randomly-selected CA with MS and similar follow-up. Outcome measures: EDSS at diagnosis, five-year follow-up, and last follow-up; time to walking assistance device; disease subtype; involved functional systems. Results: AA MS patients displayed more cerebellar dysfunction, and worse EDSS scores at diagnosis, at four to six years follow-up from diagnosis, and at last follow-up compared to the CA MS patients with similar length of follow-up. AA MS patients had earlier and more frequent gait difficulty requiring use of a cane or wheelchair. AA MS patients had a higher prevalence of primary progressive (PP) MS (22 versus 9%) and a lower rate of relapsing-remitting (RR) MS (30 versus 52%) compared to CA. Conclusions: Compared to CA patients, MS in AA is characterized by a higher incidence of cerebellar dysfunction and a more rapid accumulation of disabilities. In this cohort, AA patients had a relatively higher rate of the PPMS subtype. These data suggest the presence of fundamental differences in the clinical phenotype and the natural history of MS in AA.