Relatively Early and Late-Onset Neuromyelitis Optica Spectrum Disorder in Central China: Clinical Characteristics and Prognostic Features

Abstract

BackgroundWe aimed to analyze the clinical characteristics and prognostic features of Chinese patients with relatively late-onset neuromyelitis optica spectrum disorder (RLO-NMOSD>40 years of age at disease onset), compared with patients with relatively early onset NMOSD (REO-NMOSD, ≤ 40 years of age at disease onset).MethodsWe retrospectively reviewed the medical records of patients with NMOSD in central China (with disease courses longer than 3 years) between January 2012 and January 2021. We further analyzed the clinical and prognostic differences between patients with REO-NMOSD and RLO-NMOSD.ResultsA total of 71 patients were included in this study. The results showed that 39 (54.9%) of the patients had RLO-NMOSD. The patients with RLO-NMOSD had higher expanded disability status scale (EDSS) scores than patients with REO-NMOSD at the initial (5.0 vs. 3.0, p = 0.01), 3-month (4.0 vs. 2.5, p = 0.001), 1-year (4.0 vs. 2.5, p = 0.003), 3rd-year (3.5 vs. 3.0, p = 0.0017), and final follow-up (4.0 vs. 2.5, P = 0.002) time points. The EDSS scores of visual function were 2.0 (1.0–3.0) in REO-NMOSD and 3.0 (2.0–3.0) in RLO-NMOSD (p = 0.038) at the final follow-up time point. The locations of spinal cord lesions at transverse myelitis (TM) onset were prone to cervical cord in patients with REO-NMOSD. There were no between-group treatment differences. The risk of requiring a cane to walk (EDSS score of 6.0) increased as the age of disease onset increased: for every 10-year increase in the age of disease onset, the risk of needing a cane to walk increased by 65% [hazard ratio (HR) = 1.65, 95% CI 1.15–2.38, p = 0.007]. Another significant predictor identified in the multivariate analysis was annualized relapse rate (ARR) (HR = 2.01, 95% CI 1.09–3.71, p = 0.025). In addition, we observed a positive correlation between age at onset and EDSS scores at the final follow-up (Spearman's r = 0.426, p < 0.0001) time point. EDSS scores at different periods were significantly different between patients with RLO-NMOSD and REO-NMOSD with anti-aquaporin-4 (AQP4) IgG positive.ConclusionThe patients with RLO-NMOSD developed more severe disabilities than patients with REO-NMOSD at a variety of time periods. All of the patients may experience recurrent aggravated symptoms after their first year, with only patients with REO-NMOSD partly recovering from the 3rd year. The age at onset and ARR were the main predictors of outcomes.

Age of onset correlates with clinical characteristics and prognostic outcomes in neuromyelitis optica spectrum disorder

“…Worse prognosis and severer motor disability in LO-NMOSD have been demonstrated in several previous studies ( 5 – 8 , 17 , 25 , 28 , 29 ), as well as in the present study: the EDSS score at last follow-up increases with onset age; older age at disease onset predict motor disability and severe disability at last follow-up; patients with older age of onset progress to motor disability more quickly. The reasons for worse prognosis in LO-NMOSD were unclear yet.…”

“…On the other hand, several studies showed similar relapsing rate between LO-NMOSD and EO-NMOSD measured by ARR ( 6 , 8 ). It is proposed that ARR-1 may be more accurate to avoid inappropriately high ARR values in patients with disease duration less than 1 year ( 5 , 8 , 27 , 28 ). In line with this, ARR was not significantly correlated with onset age in our study.…”

“…The results of visual disability were inconsistent among studies. Several studies found that LO-NMOSD patients were more susceptible to visual disability ( 8 , 28 ), while others come to the opposite conclusion ( 7 , 25 , 30 ). Especially, in a large cohort from the United Kingdom and Japan, results suggested that the likelihood of developing visual disability decreases with the age of onset ( 25 ).…”