Lasting Ambulatory and Visual Disability in Patients with Neuromyelitis Optica Spectrum Disorder

Background: Neuromyelitis Optica Spectrum Disorder (NMOSD) is a rare, inflammatory CNS syndrome, which can lead to significant accrual of visual and ambulatory disability over time. Patients with NMOSD often have pathogenic autoantibodies to aquaporin-4 (AQP4-IgG) but may also have autoantibodies to myelin oligodendrocyte glycoprotein (MOG)-IgG or no autoantibodies. Due to its low incidence and prevalence, the long-term disability experienced by patients with NMOSD in relation to antibody status remains incompletely described.

Objectives: To examine differences in disability accrual among patients with NMOSD by racial group in a large academic neurology clinic in the southern United States.

Methods: All clinical records at the University of Alabama at Birmingham with an NMOSD diagnosis were found using the i2b2 search engine. A retrospective chart review was conducted to collect demographics, BMI, antibody status, and details of the clinical course. Likelihood ratio Chi-square test or Fisher’s Exact test was used for comparisons, with p<0.05 considered signficant. Analysis was completed using SPSS.

Results: A total of 121 patients (84.3% female) were found to have a diagnosis of NMOSD. Of those, 68.6% were positive for AQP4-IgG, 16.5% were positive for MOG-IgG, and 14.9% were found to be seronegative. Black patients were more likely than white patients to be AQP4-IgG positive (79.5% vs. 41.9%, p= 0.004). Patients who were AQP4-IgG positive were more likely than patients who were MOG-IgG positive or seronegative to present with Transverse Myelitis (60.2% vs. 35% vs. 38.9%, p= <0.001)

Overall, patients were most likely to only have lasting visual disability (31.4%), but a substantial number had lasting ambulatory disability (22.3%) or lasting visual and ambulatory disability (9.1%). However, patients with AQP4-IgG autoantibodies were more likely than patients with MOG-IgG or seronegative patients to have lasting ambulatory disability (62.7% vs. 5% vs. 27.8%, p=0.14). Antibody status did not affect presence of lasting visual disability among patients.

Conclusions: Lasting ambulatory, but not visual, disability differs by antibody status in patients with Neuromyelitis Optica Spectrum disorder.