Hypoxemia, Sleep Disturbances, and Depression Correlated with Fatigue in Neuromyelitis Optica Spectrum Disorder

<jats:title>Summary</jats:title><jats:sec><jats:title>Aims</jats:title><jats:p>Among patients with neuromyelitis optica spectrum disorder (<jats:styled-content style="fixed-case">NMOSD</jats:styled-content>), fatigue is commonly complained about and is one of the most debilitating symptoms. This study aimed to investigate the incidence of fatigue and explore impacting factors attributed to fatigue in <jats:styled-content style="fixed-case">NMOSD</jats:styled-content>.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>Thirty‐three patients with <jats:styled-content style="fixed-case">NMOSD</jats:styled-content> and twenty matched healthy controls were enrolled. A battery of self‐reported questionnaires was conducted to assess quality of sleep, daytime sleepiness, fatigue, depression, and level of activity of daily life. The structure of sleep was assessed by polysomnography with blood oxygen saturation monitored by noninvasive pulse oximeter. Brain and spinal cord lesions were evaluated by <jats:styled-content style="fixed-case">MRI</jats:styled-content>s.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Fatigue was more severe and more prevalent among the patients with <jats:styled-content style="fixed-case">NMOSD</jats:styled-content> compared with controls (fatigue score which ranges from 0 to 11 with higher scores indicating more severe fatigue: 6.4 ± 0.6 vs. 3.8 ± 0.4, <jats:italic>P</jats:italic> = 0.002; incidence, 64% vs. 35%, <jats:italic>P</jats:italic> = 0.043), and it was negatively associated with daily activity level (r = 0.455, <jats:italic>P</jats:italic> = 0.008). The patients with fatigue had higher Pittsburgh Sleep Quality Index score, higher Epworth Sleepiness Scale score, lower blood oxygen state, and higher depression score than patients without fatigue; blood oxygen was especially negatively correlated with fatigue (nadir SpO<jats:sub>2</jats:sub>, r = −0.558, <jats:italic>P</jats:italic> = 0.001; mean SpO<jats:sub>2</jats:sub>, r = −0.457, <jats:italic>P</jats:italic> = 0.007); depression was also positively correlated with fatigue (r = 0.599, <jats:italic>P</jats:italic> < 0.001).</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>Patients with <jats:styled-content style="fixed-case">NMOSD</jats:styled-content> experienced significant fatigue, which had an obvious impact on their daily activity. Fatigue in these patients was related to hypoxemia, sleep disturbances, and depression.</jats:p></jats:sec>