Application of the 2024 and 2017 McDonald criteria at disease onset in a multicenter Korean MS cohort

BACKGROUND: To date, real-world applications of the 2024 McDonald criteria have been limited to non-Asian cohorts, with a lack of data from Asian populations. OBJECTIVES AND METHODS: We evaluate the 2024 and 2017 McDonald criteria at disease onset in a large multicenter Korean multiple sclerosis (MS) cohort to assess differences in criteria fulfillment and time to diagnosis. RESULTS: In 306 individuals with MS, we compared the 2024 and 2017 McDonald criteria at disease onset. Under the 2024 criteria, all participants fulfilled diagnostic criteria at initial evaluation, whereas 90.5% (277/306) met the 2017 criteria. Among 22 participants with clinically isolated syndrome who fulfilled the 2024 criteria earlier than the 2017 criteria, the median time to diagnosis was reduced by 5 months. This difference was primarily attributable to the inclusion of optic nerve involvement as an additional dissemination in space site. CONCLUSION: These findings suggest that the 2024 McDonald criteria facilitate earlier MS diagnosis in real-world practice.