Clinical and polysomnographic characteristics associated to excessive daytime sleepiness in obstructive sleep apnea

Background: Obstructive sleep apnea (OSA) is characterized by recurrent episodes of reduction or cessation of upper airway airflow during sleep. One of the most frequent symptoms related to OSA is excessive daytime sleepiness (EDS), with prevalence ranging from 35 to 87%. EDS has elevated morbidity, being related, for example, to increased risk of motor vehicle and work-related accidents and impaired cognitive and work performance. However, there are few studies evaluating epidemiology and polysomnographic characteristics of EDS among individuals with OSA. Objective: To evaluate prevalence of EDS and to assess the association of clinical and polysomnographic characteristics of EDS among adult patients with OSA. Methods: This was a cross-sectional study, including adult individuals referred for diagnostic polysomnography (PSG) between March, 2014 and March, 2015. The main inclusion criteria were confirmed OSA diagnosis and age ≥18 years old. Exclusion criteria were participation refusal, age 10. Depressive and anxious symptoms were evaluated through Beck Depression Inventory and Beck Anxiety Inventory, respectively. All participants were submitted to full-night polysomnography. Results: Data from 392 participants was analyzed. EDS prevalence was 45.7%, being more prevalent in men and in the economically active group. There was a positive correlation between body mass index and ESS score and there was a negative correlation between ESS score and age. Prevalence of depressive and anxious symptoms was higher in the EDS-group. EDS was more prevalent in severe OSA. Regarding polysomnographic findings, EDS was associated with shorter sleep duration and REM sleep latency and greater apnea-hypopnea index (AHI), sleep efficiency, sleep fragmentation, and total sleep time in comparison to non-EDS ones. EDS was not associated to oxygen saturation parameters. Conclusion: Prevalence of EDS in OSA patients was within mid-range from previous studies. There is a higher prevalence of EDS between economically active young men. Besides, our findings suggest that sleep fragmentation due to respiratory events in OSA might play a role in EDS pathophysiology.