The demographic and polysomnographic predictors of excessive daytime sleepiness in sleep APNEA syndrome and the evaluation of subjective tests feasibility

Purpose: Excessive daytime sleepiness (EDS), which is important symptom for obstructive sleep apnea syndrome (OSAS), causes impairment in cognitive functions and work performance of individuals and leads to traffic and occupational accidents. Epworth sleepiness scale (ESS) is a commonly used tool because of its feasibility and cost-effectiveness, to assess daytime sleepiness and determine the effectiveness of treatment. The aim of this study is to discuss EDS with demografic and polisomnografic datas in patient with OSAS and to assess the feasibility of ESS. Methods: Patients who were evaluated in Sleep Disorders Clinic of Neurology Department of Dokuz Eylül University Faculty of Medicine, between January 2014-February 2016 and diagnosed as OSAS using polisomnography were included for the study. Data was searched retrospectively. All the adults whose excessive daytime sleepiness had been evaluated with ESS were included. Statistical analyses were performed using SPSS 15. p<0,05 was accepted as signifance level. Results: Two hundered seventy four were included for the study, (78%) 214 of them were men. Mean age of cases was 51,1211,93 years, mean body mass index (BMI) was 30,495,38 kg/m2, mean apnea-hipopne index was 37,8126,03. One hundered twenty four patients were graduated from primary school or high school, while 113 patients were graduated from university at least. Mean ESS point was found 9,875,41 in all patients. According to the severity of illness, mean ESS was found 8,94,9 in patients with mild OSAS, 9,24,8 in patients with moderate OSAS and 10,65,8 in patients with severe OSAS. There were no significant differences between groups. Correlations between ESS and BMI, age, AHI, average desaturations of O2, mean apne duration, and minimum saturation of O2 were evaluated. There was no significant correlations between these variables. When examining reliability, Cronbach's alpha was found high, 0,852, intraclass correlations was found at moderate level 0,412. With factor analysis, it was found that the scale measured one factor and that explained the 49,7% of the variance that wanted to be measured. When the analyses of the scale reapplied for the subgroups according to education level and gender, even it was found relatively lower level in women and well-educated groups, reliability of the test was assessed in good level for all subgroups. Conclusions: In this study ESS was found in high level of validity and reliability but ESS scores were low in contrast with those of the literature and not correlated with any polysomnographic values.