Twenty-seven antibody-positive children (54%) relapsed, versus 3 of the 24 negative children (13%). Relapse was almost six times more likely with MOB-Ab (95% confidence interval [CI], 1.8-19.7; P = .002). The overall relapse rate of 42% (31/74) was higher than in previous studies, probably because of longer follow-up, lasting years in some cases.
Sixteen children (22%) presented with seizures, which nearly tripled the risk of relapse, although the finding wasn’t statistically significant (95% CI, 0.9-9.2; P = .06). There was a trend toward more seizures at onset in the MOG-Ab group.
Twelve children (16.2%) developed post-ADEM epilepsy, all but one MOG-Ab positive. The median time to seizure onset was 3 months. All of the children remained on antiepileptic medications at 2-year follow-up.
Oligoclonal bands were found in 8 of 37 children tested (22%), and also markedly increased the risk of post-ADEM seizures (odds ratio, 8.7; 95% CI, 1.5-54; P = .01).