A Different Clinical Type of OSAS: REM-Related OSAS

Objective: Rapid Eye Movement (REM) is an entity in which collapsibility of upper respiratory tract increases. Different opinions have been proposed definition of REM-related obstructive sleep apnea syndrome (OSAS). Some authors classify REM-related OSAS as the first presentation or others as a different clinical type of OSAS. We aimed to compare clinical and polysomnographic findings of REM-related and non REM-related OSAS patients to test whether REM-related OSAS is a different clinical type OSAS or manifestation of early stage or onset of OSAS.
Methods: The study had a retrospective design. Patients with initial diagnosis of sleep related breathing disorders, were later diagnosed as OSAS based on apnea-hypopnea index (AHI) ≥ 5, and divided into two groups: Patients with AHINREM < 5 and, AHIREM / AHINREM >2 whose REM recordings were obtained for at least 30 minutes were defined as “REM-related OSAS”, and those who refute this description as “non REM-related OSAS.”
Results: A total of 329 cases with a mean age of 51 ± 10 years were included in the study. Thirty-five (10.6 %) cases of OSAS were REM-related, 294 (89.4 %) of them were non REM-related. Age, body mass index, smoking status, and concomitant diseases were comparable between groups (p>0.05). In REM related cases AHI were lower, duration of REM was longer, and mean oxygen saturations were comparatively higher (p<0.05).
Conclusion: Similarities between groups as for age, body mass index, concomitant disease suggest that REM-related OSAS is a different clinical type of OSAS, rather than early phase of OSAS.