Higher Percentage of Stage 1 Sleep Predicts Excessive Daytime Sleepiness in Middle-Aged Obstructive Sleep Apnea Males

Abstract

Introduction: The etiologies of excessive daytime sleepiness (EDS) in obstructive sleep apnea (OSA) remain uncertain. We found that the percentage of stage 1 sleep is an important predictor of excessive daytime sleepiness (EDS) in middle-aged OSA males.Materials and Methods: We retrospectively reviewed the polysomnography (PSG) results of 363 middle-aged OSA patients. A total of 50 patients were enrolled in the final analyses. Patients with an Epworth Sleepiness Scale (ESS) score equal to or more than 20 comprised the EDS group. Patients with an ESS score equal to or less than 4 were included in the non-EDS group. We compared the PSG results between these 2 groups of patients to survey for possible predictors of EDS in middle-aged OSA males.Results: Patients in the EDS group had a higher respiratory arousal index, total arousal index, and percentage of stage 1 sleep. In addition, both the stage 2 sleep and slow wave sleep percentages were lower in the EDS group, compared with that in the non-EDS group. Logistic regression analysis showed that a higher percentage of stage 1 sleep is an independent predictor of EDS in middle-aged OSA males.Conclusions: A higher percentage of stage 1 sleep is an important predictor of EDS in middle-aged OSA males.