BACKGROUND: Diagnosis of sleep-disordered breathing requires overnight 
recordings, such as polygraphy or polysomnography. Considering the cost and low 
availability of these procedures, preselection of patients at high risk is 
recommended. We aimed to develop a screening tool allowing identification of 
individuals at risk of sleep-disordered breathing.
METHODS: We used the participants from the population-based HypnoLaus cohort in 
Lausanne, Switzerland, who had a clinical assessment and polysomnography at 
home, to build a clinical score (the NoSAS score) using multiple factor analysis 
and logistic regression to identify people likely to have clinically significant 
sleep-disordered breathing. The NoSAS score was externally validated in an 
independent sleep cohort (EPISONO). We compared its performance to existing 
screening scores (STOP-Bang and Berlin scores).
FINDINGS: We used the 2121 participants from the HypnoLaus cohort who were 
assessed between Sept 1, 2009, and June 30, 2013. The NoSAS score, which ranges 
from 0 to 17, allocates 4 points for having a neck circumference of more than 40 
cm, 3 points for having a body-mass index of 25 kg/m(2) to less than 30 kg/m(2) 
or 5 points for having a body-mass index of 30 kg/m(2) or more, 2 points for 
snoring, 4 points for being older than 55 years of age, and 2 points for being 
male. Using a threshold of 8 points or more, the NoSAS score identified 
individuals at risk of clinically significant sleep-disordered breathing, with 
an area under the curve (AUC) of 0·74 (95% CI 0·72-0·76). It showed an even 
higher performance in the EPISONO cohort, with an AUC of 0·81 (0·77-0·85). The 
NoSAS score performed significantly better than did the STOP-Bang (AUC 0·67 [95% 
CI 0·65-0·69]; p<0·0001) and Berlin (0·63 [0·61-0·66]; p<0·0001) scores.
INTERPRETATION: The NoSAS score is a simple, efficient, and easy to implement 
score enabling identification of individuals at risk of sleep-disordered 
breathing. Because of its high discrimination power, the NoSAS score can help 
clinicians to decide which patients to further investigate with a nocturnal 
recording.
FUNDING: Faculty of Biology and Medicine of the University of Lausanne, Lausanne 
University Hospital, Swiss National Science Foundation, Leenaards Foundation, 
GlaxoSmithKline, and Vaud Pulmonary League.