BACKGROUND: Obstructive sleep apnea/hypopnea syndrome (OSAHS) is a major cause of morbidity and mortality. Different clinical models and questionnaires have been used to evaluate patients with the highest OSAHS probability.OBJECTIVES: To evaluate the clinical utility of five different questionnaires--STOP, STOPBang (SB), Berlin Questionnaire (BQ), Epworth Sleepiness Scale (ESS), and 4-Variable Screening Tool (4-V) - in a sleep clinic in order to identify patients at risk for OSAHS and to assess the best possible combination of these tools.METHODS: 1853 (74.4% males) patients (mean age 52±14 years; mean body mass index 32.8±7 kg/m2) visiting a sleep clinic were studied retrospectively.RESULTS: SB had the highest sensitivity (97.6%), the largest area under the receiver operating characteristics curve (AUC) (0.73; 95% CI, 0.7-0.76) and best OR (5.9; 95% CI, 3.6-9.5), but the lowest specificity (12.7%) for AHI > or =15. The 4-V > or = 14 had the highest specificity (74.4%) followed by ESS (67%). BQ had good sensitivity (87%), worse specificity (33%) than 4-V and ESS but better than STOP (13%) and SB (12.7%). The combination of questionnaires did not improve their predictive value.CONCLUSIONS: SB had the highest sensitivity, OR, and AUC, but rather low specificity, and 4-V the highest specificity. The combination of different questionnaires did not improve their predictive value.