BACKGROUND: There is a growing number of patients with sleep-disordered 
breathing (SDB) referred to sleep clinics. Therefore, a simple but useful 
screening tool is urgent. The NoSAS score, containing only five items, has been 
developed and validated in population-based studies.
AIM: To evaluate the performance of the NoSAS score for the screening of SDB 
patients from a sleep clinic in China, and to compare the predictive value of 
the NoSAS score with the STOP-Bang questionnaire.
METHODS: We enrolled consecutive patients from a sleep clinic who had undergone 
apnea-hypopnea index (AHI) testing by type III portable monitor device at the 
hospital and completed the STOP-Bang questionnaire. The NoSAS score was assessed 
by reviewing medical records. Sensitivity, specificity, positive predictive 
value, negative predictive value, and area under the receiver operating 
characteristic curve (AUC) of both screening tools were calculated at different 
AHI cutoffs to compare the performance of SDB screening.
RESULTS: Of the 596 eligible patients (397 males and 199 female), 514 were 
diagnosed with SDB. When predicting overall (AHI ≥ 5), moderate-to-severe 
(AHI ≥ 15), and severe (AHI ≥ 30) SDB, the sensitivity and specificity of the 
NoSAS score were 71.2, 80.4, and 83.1% and 62.4, 49.3, and 40.7%, respectively. 
At all AHI cutoffs, the AUC ranged from 0.688 to 0.715 for the NoSAS score and 
from 0.663 to 0.693 for the STOP-Bang questionnaire. The NoSAS score had the 
largest AUC (0.715, 95% CI: 0.655-0.775) of diagnosing SDB at AHI cutoff of ≥5 
events/h. NoSAS performed better in discriminating moderate-to-severe SDB than 
STOP-Bang with a marginally significantly higher AUC (0.697 vs. 0.663, P=0.046).
CONCLUSION: The NoSAS score had good performance on the discrimination of SDB 
patients in sleep clinic and can be utilized as an effective screening tool in 
clinical practice.