What is the relapse rate of myelin oligodendrocyte glycoprotein antibody‑associated disease (MOGAD) in adults?

Relapse Rate in MOGAD

The relapse rate in adults with MOGAD ranges from 36-57%, with most relapses occurring within the first year after diagnosis, and approximately 50-60% of patients experience relapses during corticosteroid dose reduction.

Overall Relapse Rates by Population

• Adult MOGAD patients have a relapse rate of approximately 56-57% in North American cohorts, which is notably higher than previously reported rates 1, 2
• The 8-year cumulative relapse risk is 36.3% in a large UK prospective cohort, though this may underestimate true relapse rates as it represents incident cases diagnosed before a second attack 3
• Pediatric MOGAD shows a 46% relapse rate over a mean follow-up of 3.9 years, with female sex and Hispanic/Latino ethnicity associated with higher relapse risk 4

Critical Timing Considerations

• Most relapses occur within the first year after diagnosis, making this a high-risk period requiring close monitoring 1
• 40% of first relapses occur immediately following withdrawal of acute treatment, particularly after stopping corticosteroids from the initial attack 2
• 50-60% of patients relapse during corticosteroid dose reduction, which is why maintenance immunosuppression should be initiated early rather than waiting for a second attack 5

Factors Associated with Higher Relapse Risk

Demographics

• Young adult age (18-40 years) carries 2.7-fold higher relapse risk compared to older adults (>40 years) 3
• Female sex increases relapse risk by 66% compared to males in pediatric cohorts 4
• Hispanic/Latino ethnicity increases relapse risk by 77% compared to non-Hispanic patients 4

Clinical Presentation

• Optic neuritis at onset is associated with 2.66-fold higher relapse risk compared to transverse myelitis at onset, though this association loses statistical significance when adjusted for follow-on corticosteroid use 3
• Any transverse myelitis at onset (alone or combined with other presentations) reduces relapse risk by 59% compared to presentations without myelitis 3
• ADEM presentation is more common in children (68% of those <12 years) but does not clearly predict relapse risk 3

Monophasic vs. Relapsing Disease

• 43-44% of MOGAD cases follow a monophasic course, meaning they never relapse after the initial attack 1, 2
• Predicting which patients will have monophasic disease remains extremely difficult, as no single factor reliably distinguishes monophasic from relapsing courses at disease onset 2
• MOG-IgG antibody titers, CSF findings, and initial presentation phenotype do not reliably predict relapse risk in most studies 2
• 5-10% of patients may convert to seronegative status, and some of these patients can still relapse, indicating antibody disappearance does not guarantee monophasic disease 2

Impact of Maintenance Therapy on Relapse Rates

Without Maintenance Therapy

• The annualized relapse rate off treatment ranges from 0.97-1.0 relapses per year in relapsing patients 2
• 64% of patients who started disease-modifying therapy before their first relapse remained monophasic, suggesting early treatment may prevent relapses 2

With Maintenance Therapy

• Maintenance prednisolone reduces relapse risk by 67% compared to no treatment when adjusted for covariates 3
• First-line immunosuppression (prednisolone, nonsteroidal agents, or combined) reduces relapse risk by 49% compared to no treatment 3
• IVIG shows the lowest annualized relapse rate of 0.13 with 72% relapse-freedom probability after at least 6 months of therapy 6
• Mycophenolate mofetil has an annualized relapse rate of 0.32 with 49% relapse-freedom probability, and shows particularly good efficacy in pediatric-onset disease (ARR 0.15) 6
• B-cell depletion therapy has an annualized relapse rate of 0.51 with only 33% relapse-freedom probability, which is surprisingly lower efficacy than other agents 6
• Rituximab or IVIG initiated shortly after onset is associated with lower risk of second events in pediatric patients 4

Common Pitfalls in Assessing Relapse Risk

• Do not assume low antibody titers predict monophasic disease, as titers fluctuate with disease activity and treatment status 5
• Do not stop monitoring patients who become seronegative, as some seronegative patients still relapse 2
• Do not taper steroids rapidly after the acute attack, as 40% of first relapses occur during treatment withdrawal 2
• Do not wait for a second attack to initiate maintenance therapy in high-risk patients (young adults, females, Hispanic/Latino ethnicity, optic neuritis presentation), as early treatment may prevent relapses 4, 3
• Recognize that 50% of patients on disease-modifying therapy continue to have disease activity, requiring treatment adjustment, so ongoing monitoring is essential even on maintenance therapy 2