The clinical significance of REM-predominant obstructive sleep apnea: a retrospective observational study

<bold>Introduction:</bold> Obstructive sleep apnea (OSA) and rapid eye movement (REM) sleep fragmentation have independently been associated with anxiety, depression and a lower quality of life. However, the clinical significance of OSA occurring predominantly in the REM phase (REM-OSA) remains unclear. <bold>Aim:</bold> To determine whether there is a difference in symptom burden between REM-OSA compared to non-REM(NREM) OSA. <bold>Methods:</bold> Patients diagnosed with OSA in the University Hospital of Brussels, a tertiary center, between 25-11-2019 and 19-09-2020, were eligible. REM-OSA was identified based on an apnea hypopnea index REM/NREM ratio of at least 2. Patients with severe OSA were excluded due to the lower prevalence of REM-OSA in severe OSA. All patients completed the Hospital Anxiety and Depression Scale, Big Five Inventory-2, SF-36 Health Survey Questionnaire, Pittsburgh Sleep Quality Index, Insomnia Severity Index, Fatigue Assessment Scale, Checklist Individual Strength, Epworth Sleepiness Scale and Stanford Sleepiness Scale (SSS) at diagnosis. <bold>Results:</bold> 224 patients with REM-OSA (119 mild and 105 moderate) and 151 patients with NREM-OSA (59 mild and 92 moderate) were included. In the mild group, those with REM predominance reported higher levels of sleepiness (SSS score of 3 compared to 2 in the NREM group) (p = 0.028). In the moderate group, REM-OSA patients reported more limitations in quality of life due to emotional health (SF-36) (p = 0.035). There was, however, no significant difference concerning anxiety, depression, personality traits, sleep quality or fatigue. <bold>Conclusion:</bold> Apneas occurring in REM sleep may have a greater impact on daytime sleepiness and perceived emotional well-being.