[Long-term prognostic follow-up study of multiphasic myelin oligodendrocyte glycoprotein antibody-associated disease in children].

Objective: To investigate the long-term prognosis and related factors in children with multiphasic myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Methods: A bidirectional cohort study was conducted. This study included 41 children with MOGAD who were treated at the Children's Medical Center of Peking University First Hospital between January 2013 and December 2024, with a disease duration of ≥5 years. Demographic characteristics, clinical episodes, therapy, and prognostic indicators (including the expanded disability status scale (EDSS) and modified Rankin scale (mRS)) were collected. Children were stratified into relapse and non-relapse groups based on the presence or absence of relapse within 5 years of the last follow-up. χ2 test or Mann-Whitney U test was used to analyze factors associated with relapse. The Log-rank test was used to compare relapse-free rates between children with disease onset 0-<5 years and those with onset at 5-10 years. Results: A total of 41 children were enrolled, including 20 boys and 21 girls. The age at onset was 5.3 (3.8, 8.5) years, the age at last follow-up was 16.1 (13.2, 17.5) years, and the disease duration was 9.4 (8.1, 10.9) years. The annualized relapse rate (ARR) during follow-up was 0.34 (0.19, 0.56) times/year. The duration to first relapse was 0.8 (0.4, 1.5) years. At the last follow-up, the EDSS score was 0.0 (0.0, 0.0) score, and the mRS score was 0 (0, 0) score. A total of 40 children (98%) experienced relapses within the first 5 years after onset, while only 1 child (2%) relapsed at 6.7 years. The relapse rate between 5-10 years was lower than that 0-<5 years (HR=0.27, 95%CI 0.16-0.47, P<0.001). A total of 25 children (61.0%) exhibited clustered relapses during the disease course. There were 20 children (49%) in non-relapse groups, who were aged 16.6 (14.8, 17.6) years, disease duration 9.8 (9.3, 10.8) years at the last follow-up. Among those 20 children, 15 children (75%) had discontinued corticosteroids and immunosuppressants. The relapse group had higher clinical event rates and ARR compared to the relapse-free group (both P<0.01), the age at last follow-up was yonger (P<0.05), while no significant differences were observed in age at onset, disease duration, or timing of immunosuppressant use (all P>0.05). Conclusions: Pediatric multiphasic MOGAD generally has a favorable prognosis, about half of patients remain relapse-free for ≥5 years at last follow-up. Relapses predominantly occur early in the disease course (mostly within 5 years of onset) and often exhibit a clustered pattern.