Fewer relapses and worse outcomes of patients with late-onset myelin oligodendrocyte glycoprotein antibody-associated disease.

Background: To delineate the clinical characteristics and outcomes of late-onset myelin oligodendrocyte glycoprotein antibody-associated disease (LO-MOGAD) and compare them with those of early-onset MOGAD (EO-MOGAD).

Methods: This observational cohort study included 199 adult patients with MOGAD. We reviewed the patients' demographic and clinical data and performed comparative analyses between EO-MOGAD and LO-MOGAD (onset age 18-50 and ≥50 years, respectively).

Results: Among the 199 patients, 42 had LO-MOGAD. Compared with patients with EO-MOGAD, those with LO-MOGAD patients exhibited a significantly higher incidence of optic neuritis both at the initial attack (66.67% vs 43.31%, p=0.007) and throughout all attacks (72.15% vs 52.51%, p=0.001). Over a similar disease duration, patients with LO-MOGAD exhibited significantly fewer relapsing courses (45.16% vs 70.97%), higher Expanded Disability Status Scale (EDSS) and visual functional system scores at the last visit (all p<0.05). Compared with patients with EO-MOGAD, those with LO-MOGAD had a significantly lower risk of relapse (HR 0.512, 95% CI 0.268 to 0.978, p=0.034), but higher risks of reaching EDSS ≥2 (HR 2.893, 95% CI 1.524 to 5.494, p<0.001) and visual acuity ≤0.6 (HR 3.097, 95% CI 1.073 to 8.937, p=0.022). Immunosuppressive therapies significantly reduced the annualised relapse rates of patients with LO-MOGAD, although adverse events leading to drug discontinuation and hospitalisation were observed.

Conclusions: Compared with patients with EO-MOGAD, patients with LO-MOGAD exhibited fewer relapsing courses but worse disability outcomes and should be actively treated.