Age-stratified clinical characteristics and disability outcomes in neuromyelitis optica spectrum disorder: A cross-sectional study.

BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the central nervous system in individuals of any age group. Age-related differences may influence disease severity, treatment response, and long-term functional outcomes. However, age-related characteristics of pediatric-onset (PO-), early-onset (EO-), and late-onset (LO-) NMOSD remain incompletely understood. The purpose of this study was to compare these three groups in various features and to identify the relationship between age at initial disease presentation and disability profile in NMOSD. METHODS: This study included 72 AQP4-positive NMOSD patients in Isfahan, Iran, between March and November 2024. Patients were categorized based on age at NMOSD diagnosis into PO (< 18 years), EO (18-49 years), and LO (≥ 50 years) groups. Logistic regression analysis was used to evaluate the associations between age at NMOSD diagnosis and disability. RESULTS: Among 72 patients, 6 were classified as PO-NMOSD, 55 as EO-NMOSD, and 11 as LO-NMOSD. Age at NMOSD diagnosis was positively correlated with EDSS at disease diagnosis (r = 0.42, p < 0.001) and current EDSS (r = 0.37, p = 0.002). In multivariable analysis, older age at NMOSD diagnosis was significantly associated with both higher disability at diagnosis (OR = 1.14, p < 0.001) and current disability status (OR = 1.1, p < 0.001). CONCLUSION: Older age at NMOSD diagnosis may be associated with greater disability burden. Age at diagnosis may represent a relevant clinical factor when evaluating disability burden in NMOSD. Further prospective multicenter studies are warranted to better define longitudinal outcomes and prognostic factors in LO-NMOSD.