Comparison between Epworth Sleepiness Scale and Polysomnographic Parameters in Patients with Obstructive Sleep Apnea Syndrome

Introduction: Obstructive sleep apnea syndrome (OSAS) is the most common sleep-related respiratory disorder. With the purpose of assisting in the screening or evaluation of OSAS patients, some scales and questionnaires were proposed. Objective: To evaluate and critically compare the relationship of excessive daytime sleepiness with the presence or absence of OSAS, in addition to other polysomnographic data. Material and method: Systematic review of the literature. Results: Six studies were included, with a total of 4258 patients; four studies demonstrate association between the Epworth sleepiness scale and the hypopnea apnea index (AIH); of those, two studies showed significant differences between ESS score and OSAS severity. Five studies (4233 patients) demonstrated lower minimum oxygen saturation in the group with excessive daytime sleepiness. There was an increase in sleep efficiency in in patients with excessive daytime sleepiness, as per the results of 3 studies (3002 patients). Discussion: The relationship between the presence of excessive daytime sleepiness and OSAS is still questioned, and its pathophysiological mechanism uncertain. Excessive daytime sleepiness secondary to OSAS seems to be an independent event, related to nocturnal hypoxemia and sleep fragmentation. Conclusion: The confidence intervals obtained from these studies do not provide clinical safety to use the Epworth sleepiness scale for screening or stratifying the risk of patients suspected of having sleep apnea.