Objective:

To determine relapse risk among incident myelin oligodendrocyte glycoprotein antibody–associated disease (MOGAD) patients in a contemporary population-based cohort.

Background:

Prior studies likely overestimated MOGAD relapse risk because many didn’t exclude patients diagnosed due to relapses, were conducted prior to widespread availability of testing, and/or were not population-based.

Design/Methods:

Results:

We identified 69 patients diagnosed prior to relapse. 30 (43.5%) were under 18 years old and 36 (52.2%) were female. Most (82.3%) made full recoveries, only 3 (4.3%) were left with moderate-to-severe deficits (all non-relapsers), even though 56.5% had severe deficits at nadir. After a median follow-up of 32.9 months (IQR=23.0-48.9), only 3 (10%) pediatric and 5 (12.8%) adult patients relapsed. Relapses occurred shortly after symptom onset (median=2.8 months, IQR=2.2-8.1). Once prophylactic treatment was initiated in relapsing patients, no further relapses occurred. Treatment was initiated shortly after symptom onset in most patients (n=65), primarily with corticosteroids (n=63, median=8 days, IQR=5-17). 31.9% received additional acute treatment but empiric prophylaxis was uncommon (15.9% total, 8.7% for diagnostic uncertainty). The length of corticosteroids ranged from 0-135 days (median=15) and longer tapers were not associated with reduced risk of relapse. The only clinical, laboratory or demographic characteristics associated with an increased risk of relapse was living an area with a higher social vulnerability index (100% relapsers, 62.2% non-relapsers), although this did not reach statistical significance (p=0.078).

Conclusions:

These findings are reassuring for newly diagnosed people with MOGAD because if acute treatment is started promptly, the risk of relapses and permanent deficits is low. These findings do not support initiating empiric prophylaxis or prolonged corticosteroid tapers in most new-onset MOGAD patients.