Objective: The aim of this study was to analyze the clinical and polysomnographic features of rapid eye movement (REM)-specific sleep disordered-breathing (SDB).
Patients and methods: All cases of sleep apnea-hypopnea syndrome (SAHS) (apnea-hypopnea index [AHI]#>10/h) diagnosed using overnight polysomnography during the period 2004 to 2006 were analyzed retrospectively. Those cases in which the ratio of AHI during REM sleep to AHI during non-REM sleep was more than 2 were classified as REM-specific SDB. We recorded the following data: clinical signs and symptoms related to SAHS, PSG results, cardiovascular risk factors, and previous cardiovascular events. Logistic regression analysis was used to identify predictors of REM-specific SDB and to analyze the possible interactions between variables.
Results: A total of 419 patients were analyzed, of whom 138 (32.9%) presented REM-specific SDB. This condition was more common in patients with mild to moderate SAHS than in those with more severe cases (odds ratio, 8.21; 95% confidence interval, 4.83-14.03). The variables independently associated with REM-specific SDB in the logistic regression analysis were female sex, lower AHI, and higher body mass index. No interactions between the main variables studied were found. There were no differences between patients with REM-specific SDB and those with non-REM-specific SDB with regard to signs and symptoms related to SAHS, excessive daytime sleepiness, sleep architecture, cardiovascular risk factors, or history of cardiovascular episodes.
Conclusions: REM-specific SDB could be considered an initial stage of SAHS that mainly affects obese women with mild to moderate sleep disorders, and that does not differ from non-REM-specific SDB in terms of clinical presentation, sleep architecture, or cardiovascular comorbidity.