A Different Clinical Type of OSAS: REM-Related OSAS

Abstract

Objective: Rapid eye movement (REM) is an entity in which the collapsibility of upper respiratory tract increases. Different opinions have been proposed with regard to the definition of REM-related obstructive sleep apnea syndrome (OSAS). Some authors consider REM-related OSAS as the first presentation, and others consider it as a different clinical type of OSAS. We aimed to compare the 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 the manifestation of early stage or the onset of OSAS. Methods: The study had a retrospective design. Patients with an initial diagnosis of sleep-related breathing disorders were later diagnosed to have OSAS based on an apnea-hypopnea index (AHI) of >= 5 and were divided into the following two groups: patients with AHINREM of <5 and AHIREM/AHINREM of >2 whose REM recordings were obtained for at least 30 min were defined as having REM-related OSAS, and those who did not meet this description were defined as having non-REM-related OSAS. Results: A total of 329 patients with a mean age of 51 +/- 10 years were included in the study. Thirty-five (10.6%) patients with OSAS were REM-related and 294 (89.4%) were non-REM-related. Age, body mass index, smoking status, and concomitant diseases were comparable between groups (p>0.05). In REM-related patients, AHI was lower, REM duration was longer, and mean oxygen saturations were comparatively higher (p<0.05). Conclusion: Similarities between groups in age, body mass index, and concomitant disease suggest that REM-related OSAS is a different clinical type of OSAS, rather than the early phase of OSAS.