Evaluation of the Relationship Between Subjective Excessive Daytime Sleepiness and Polysomnographic Respiratory Variables in Adult Obstructive Sleep Apnea Syndrome

Abstract

Objective: Excessive daytime sleepiness (EDS), a symptom of obstructive sleep apnea syndrome (OSAS), is an important cause of morbidity. It is frequently evaluated using the Epworth sleepiness scale (ESS) in clinical practice. This study was conducted to investigate the relationship between EDS and polysomnographic respiratory parameters in OSAS patients. Materials and Methods: The records of 274 adult patients who applied to our sleep and disorders unit between 2014 and 2016 and were polysomnographically diagnosed with OSAS were retrospectively reviewed. EDS was evaluated subjectively with ESS; OSAS patients were divided into two groups: those with EDS (ESS total score >10) and those without (ESS total score ≤10). Clinical and polysomnographic data were then compared between the study groups. Results: While there was no significant difference in terms of age, gender, and mean apnea durations (p>0.05) between the two groups with and without EDS, body mass index (BMI), apnea-hypopnea index (AHI), mean O2 desaturation was higher and minimum O2 saturation was lower (p<0.05) in the group with EDS. While there was no significant correlation between the ESS total score and age and mean apnea duration, there was a weak positive correlation between the ESS total score and BMI, AHI, mean O2 desaturation, hourly desaturation duration percentage, and desaturation depth; a very weak and negative significant correlation was found with minimum O2 saturation. Conclusion: EDS observed in OSAS is weakly related to standard polysomnographic respiratory parameters and composite respiratory indices, and it should be evaluated with other indicators of inflammation and oxidative stress caused by intermittent hypoxia.

Keywords

• excessive daytime sleepiness
• epworth sleepiness scale
• obstructive sleep apnea syndrome