BACKGROUND: Diagnosis of sleep-disordered breathing (SDB) requires overnight 
polysomnography (PSG). Because of the cost and low availability of these 
procedures, the NoSAS score was developed to identify subjects at high risk of 
SDB. To evaluate the clinical utility of the NoSAS score for screening patients 
with SDB in China and to compare the predictive value of the NoSAS score with 
the Epworth Sleepiness Scale (ESS), we used the STOP-Bang questionnaire and the 
Berlin questionnaire.
METHODS: In our study, we retrospectively reviewed the existing clinical data of 
patients who underwent an overnight PSG for suspected SDB from June 2014 to 
September 2017 at the sleep medical center of Guangdong Medical University 
Affiliated Second Hospital. The information we collected included all parts of 
the NoSAS score, the ESS, the STOP-Bang questionnaire and the Berlin 
questionnaire. Based on the severity of SDB determined by the apnea-hypopnea 
index (AHI), the patients were classified into four groups of primary snoring 
(<5 events/h), mild SBD (AHI ≥5 and <15 events/h), moderate SBD (AHI ≥15 and ≤30 
events/h) and severe SBD (>30 events/h). We calculated the sensitivity, 
specificity, positive predictive value, negative predictive value and area under 
the receiver operating characteristic curve of the five questionnaires to 
compare their relative efficacy for screening SDB.
RESULTS: A total of 479 consecutive patients (374 males and 105 females) ranging 
in age from 18 to 80 years old (mean ± SD, 48.9±14.4 years old) were recruited 
into this study. When using the standard of AHI ≥5 for diagnosing SDB, the NoSAS 
score had the largest area under the curve (AUC) (AUC =0.734), and the Berlin 
questionnaire (AUC =0.732) came second. Both exhibited a better predictive value 
than the ESS score and the STOP-Bang questionnaire. Using NoSAS ≥8 to predict 
AHI ≥5 events/h, AHI ≥15 events/h and AHI >30 events/h, the sensitivity and 
specificity were 0.590 and 0.707, 0.649 and 0.626, and 0.644 and 0.562, 
respectively; for the STOP-Bang questionnaire, the values were 0.721 and 0.512, 
0.752 and 0.440, and 0.763 and 0.399, respectively; and for the Berlin 
questionnaire, the values were 0.721 and 0.512, 0.752 and 0.440, and 0.763 and 
0.399, respectively.
CONCLUSIONS: The NoSAS score and the Berlin questionnaire both exhibited good 
predictive value for SDB patients. NoSAS is a more suitable questionnaire to use 
in clinic for the conveniences but the similar performance with another 
questionnaire.