Background: Obstructive sleep apnea (OSA) is an independent risk factor for complications after surgery. However, OSA remains largely under recognized, and questionnaires designed to detect OSA have shown inconsistent results. Patients with cardiovascular diseases may not present with the typical symptoms of OSA. We therefore sought to compare the performance of screening questionnaires of patients referred for coronary artery bypass grafting (CABG) versus abdominal surgery (Abd surgery).
Methods: We studied 40 consecutive patients referred for CABG [29 men; age 56 ± 7 years; body mass index (BMI) 30 ± 4 kg/m(2)], and 41 referred to Abd Surgery matched for age, gender, and BMI (28 men; age 56 ± 8 years; BMI 29 ± 5 kg/m(2)). All patients were evaluated with validated questionnaires to predict OSA (STOP-Bang and Berlin), Epworth sleepiness scale (ESS) and full overnight polysomnography.
Results: The prevalence of OSA (apnea-hypopnea index ≥15 events/hour) in the CABG and Abd surgery groups was similar (52 and 41 %, respectively, p = 0.32). The Berlin questionnaire showed similar sensitivity (67 vs. 82 %, p = 0.17) but lower specificity in the CABG group (26 vs. 62 %, p = 0.02). The STOP-BANG questionnaire had a high sensitivity (90 vs. 94 %, p = 0.42) but low specificity (5 vs. 13 %, p = 0.25) in the CABG and Abd surgery groups, respectively. Patients referred for CABG slept less (323 [285-376] vs. 378 [308-415] minutes, p = 0.04) but had lower levels of daytime sleepiness than Abd surgery patients had (ESS, 6 ± 4 vs. 9 ± 5; p = 0.01, respectively).
Conclusions: Presenting clinical characteristics of OSA are modulated by the population evaluated and may affect the performance of screening questionnaires.