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Updated: Aug 6, 2026
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Published on: December 9, 2015
Impact of Relapse Burden on Recovery and Disability Following Acute Attacks in Neuromyelitis Optica Spectrum
Matina Chaiwarut1, Kwanpat Primsirikunawut1, Tanakrit Ananrattanawimol1
1Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
Background:
Neuromyelitis optica spectrum disorder (NMOSD) is a relapsing autoimmune disease in which disability is largely relapse-driven. The effect of relapse burden on post-relapse recovery remains unclear.
Methods:
This retrospective cohort study included adult patients with NMOSD who experienced clinical relapse at a tertiary care center in Northern Thailand between 2015 and 2024. Relapse episodes were stratified by prior relapse burden into no prior relapse, low relapse burden (1-2 prior relapses), and high relapse burden (>2 prior relapses). Outcomes included Expanded Disability Status Scale (EDSS) at relapse nadir and at 90 and 180 days. Unfavorable outcome was defined as EDSS ≥6. Recovery was assessed using the Recovery Index (RI).
Results:
A total of 148 patients contributed 493 relapse episodes. Higher relapse burden was associated with progressively greater proportions of unfavorable outcomes at 90 and 180 days (P<0.001). At 90 days, unfavorable outcomes occurred in 4.7%, 12.0%, and 34.9% of no-prior-relapse, low-relapse-burden, and high-relapse-burden episodes, respectively. At 180 days, corresponding proportions were 2.0%, 8.3%, and 27.8%. EDSS at nadir and follow-up increased stepwise with higher relapse burden, whereas RI was progressively lower at both time points (all P<0.001). Each additional prior relapse and delayed intravenous methylprednisolone initiation >14 days after relapse onset were independently associated with unfavorable outcomes at both 90 and 180 days.
Conclusion:
Higher prior relapse burden was associated with more severe attacks, greater post-relapse disability, and less complete recovery. Relapse prevention, early attack recognition, and timely acute treatment may reduce disability accumulation in NMOSD.
