PURPOSE: Several questionnaires are available for the screening of obstructive 
sleep apnea (OSA). Herein, we compare the performance characteristics of nine 
available questionnaires for assessing the likelihood of OSA.
METHODS: Consecutive subjects who underwent polysomnography at the sleep 
laboratory of the unit were included. Subjects with obstructive events and apnea 
hypopnea index (AHI) ≥5 were considered to have OSA. The likelihood ratios (LRs) 
and other performance characteristics were calculated for the following nine 
questionnaires: Berlin, modified Berlin, STOP, STOP-Bang and OSA50 
questionnaires, sleep apnea clinical score (SACS), Epworth sleepiness scale 
(ESS), American Society of Anesthesiologists (ASA) checklist, and the elbow sign 
questionnaire.
RESULTS: Two-hundred and ten subjects (mean age, 46.5 years; mean body mass 
index [BMI], 31.9 kg/m2; 27.1% women) were included. OSA was diagnosed in 78.1% 
of patients; 49.5% had severe OSA (AHI ≥30). The SACS questionnaire had the 
highest positive LR (LR+, 5.6) and positive predictive value (95.2%). The 
modified Berlin questionnaire had the best negative LR (LR-, 0.2) and the 
highest negative predictive value (57.1%). The STOP-Bang questionnaire also had 
an LR- of 0.2 if BMI threshold of 25 kg/m2 (like that in the modified Berlin 
questionnaire) was used. Among individual items of various sleep questionnaires, 
the highest LR+ was obtained for neck circumference >43 cm (LR+, 4.9), while the 
best LR- was obtained for snoring and BMI >25 kg/m2 (LR-, 0.2).
CONCLUSIONS: The SACS and the STOP-Bang questionnaires (BMI threshold of 
25 kg/m2) were found to provide the best positive and negative LRs, 
respectively, for the prediction of OSA. We believe that information from these 
questionnaires may help in prioritizing patients for sleep studies in 
high-volume centers.