Supplementary Material for: Clinical Characteristics of Chinese Male Patients with Aquaporin-4 Antibody-Positive Late-Onset Neuromyelitis Optica Spectrum Disorder

<b><i>Background and Objective:</i></b> Limited studies are available for male patients with anti-aquaporin-4 antibody (AQP4-Ab)-positive late-onset neuromyelitis optica spectrum disease (LONMOSD). The aim of this study was to investigate the clinical characteristics of Chinese male patients with AQP4-Ab-positive LONMOSD. <b><i>Methods:</i></b> We retrospectively reviewed the medical records of 12 male patients with LONMOSD, 16 male patients with early-onset NMOSD (EONMOSD), and 64 female patients with LONMOSD. These enrolled patients were classified according to the age of onset: LONMOSD (≥50 years of age at onset) versus EONMOSD (&lt;50 years of age at onset). Clinical characteristics and magnetic resonance imaging (MRI) findings were collected. All included patients were positive for AQP4 antibody. <b><i>Results:</i></b> Compared with female LONMOSD patients, male LONMOSD patients had less frequent transverse myelitis (TM) at onset (8.33 vs. 53.13%, <i>p</i> = 0.004) and lower Expanded Disability Status Scale (EDSS) scores (median 1 vs. 4, <i>p</i> = 0.036). Compared with male EONMOSD patients, male LONMOSD patients had a shorter time from onset to diagnosis (0.85 months vs. 6.00 months, <i>p</i> = 0.04). <b><i>Conclusion:</i></b> Less common TM at onset, less disease severity, and shorter time from onset to diagnosis probably occur in male LONMOSD patients.