OBJECTIVE: The STOP-Bang questionnaire was developed as a quick and simple 
screening tool for obstructive sleep apnea (OSA) in preoperative clinics. We 
aimed to evaluate the validity of the STOP-Bang questionnaire to predict 
moderate-to-severe and severe OSA in the general population.
METHODS: A sample of 242 subjects selected from a population-based cohort in 
Singapore completed home-based sleep testing with a type 3 monitor. Subjects 
were asked to complete the STOP questionnaire while body mass index (BMI), age, 
neck circumference, and sex were recorded. A score of ≥3 on the questionnaire 
indicated high risk of OSA.
RESULTS: A total of 68 subjects (28.1%) and 26 subjects (10.7%) had an 
apnea-hypopnea index (AHI) of ≥15 and ≥30 events per hour, respectively. Of the 
subjects, 89 (36.8%) were classified as high risk based on the questionnaire. 
The sensitivity of a STOP-Bang score of ≥3 was 66.2% to detect AHI ≥15 and 69.2% 
to detect AHI ≥30. The specificities were 74.7% and 67.1%, respectively. The 
negative predictive values were 85% for moderate-to-severe OSA and 94.8% for 
severe OSA. The corresponding positive predictive values were 50.6% and 20.2%, 
respectively. Using BMI cutoffs of 30 and 27.5 for Asians compared to the 
original cutoff of 35 did not improve the questionnaire performance 
significantly.
CONCLUSION: The STOP-Bang questionnaire can be used as a screening tool in the 
general population in view of its moderate sensitivity and high negative 
predictive value for subjects with moderate-to-severe and severe OSA. The cutoff 
of BMI >35 can be used in Asians, as lower BMI cutoffs did not improve 
questionnaire performance.