Investigate the correlation between the epworth sleepiness scale and PSG in diagnosis of obstructive sleep apnea-hypopnea syndrome

Objective To assess the correlation between the epworth sleepiness scale (ESS) and PSG in diagnosis of obstructive sleep apnea-hypopnea syndrome (OSAHS).Methods 255 subjects (aged≥ 20) were selected from multistage stratified cluster sampling of 1 534 moderate and severe snorers based on the Epworth sleepiness scale (ESS≥3,ESS≥6 and ESS≥9) from the prevalence of OSAHS in ningxia in June 2007 and December 2008.The questionnaire concerning snoring,daytime sleepiness (ESS) was comlpeted,the height,weight,neck girth were measured and the portable polysomnographys (PGS) for the whole night was tested.All analyses were done with SPSS version 16.0 for windows.Descriptive statistics of all continuous variables were calculated as means and standard deviation.A comparison between groups was done using Chi-square test,and spearman test was used for ESS between PSG,and then ROC curve was done based on golden criterion AHI≥5.There was moderate statistical accuracy when the area under ROC between 0.7 and 0.9.The optimal operating point,the best sensitivity and specificity was done by using cross-over method.Results Two hundred and fifty-five subjects had answered the questions,and 251(98.43％) were available for evaluation,male 177(70.52％),female 74 (29.48％);Han nation 131(52.20％),Hui nation 120 (47.80％) ; urban citizen 127(50.60％),rural residents 124(49.40％),snorer 73,mild OSAHS 127,moderate 21 and severe OSAHS 30.The ESS had positive correlation with AHI and negative with SaO2.The ESS showed moderate diagnostic value of OSAHS.Based on ROC curve,ESS at the optimal operating point of 7.5 had a greater sensitivity and specificity for diagnosis of OSAHS.After defining AHI≥5 and ESS≥9 as a criteria,the conservatively estimated prevalence of OSAHS was 3.41％ in Ningxia.Conclusions The ESS had positive correlation with AHI and negative with SaO2. Key words: Snoring;  Obstructive sleep apnea-hypopnea syndrome;  Epworth sleepiness scale;  Polysomnographys ;  Correlation