REM-predominant obstructive sleep apnea: an unmet clinical need.

Purpose: Obstructive sleep apnea (OSA) and rapid eye movement (REM) sleep fragmentation are associated with increased fatigue, sleepiness, anxiety and depressive symptoms. However, the clinical significance of REM-predominant OSA (REM-OSA) remains less clear.

Aim: To determine any differences in symptom-burden between REM-OSA and non-REM (NREM) OSA.

Methods: Patients diagnosed with OSA at a University Hospital in Brussels between 25-11-2019 and 19-09-2020 were eligible. REM-OSA was defined as an apnea hypopnea index REM/NREM ratio of at least 2 with a minimum REM-time of 30 min. Severe OSA was excluded due to the expectedly lower prevalence of REM-OSA in this group. All patients completed the Hospital Anxiety and Depression Scale, Big Five Inventory-2, DS-14 questionnaire, 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 at diagnosis.

Results: 209 patients with REM-OSA (112 mild and 97 moderate) and 132 with NREM-OSA (48 mild and 84 moderate) were included. Patients with mild REM-OSA were twice as likely to have a SSS score of 3 or more (defined as excessive daytime sleepiness) compared to NREM-OSA (odds ratio 2.1591, p-value 0.0359). There was no significant difference in anxiety, depression, personality traits, fatigue or sleep quality.

Conclusion: For mild OSA, a predominance of obstructive respiratory events during the REM phase results in a greater impact on excessive daytime sleepiness. To address this symptom, a lower treatment threshold to include symptomatic mild REM-OSA patients may be warranted.