Obstructive sleep apnea prevalence and adverse respiratory events in surgical patients.

In the article ‘‘Patients with a high risk for obstructive sleep apnea syndrome: Postoperative respiratory complications’’ by Pereira et al., the authors aim to evaluate the incidence of STOP-BANG score ≥ 3, in surgical patients admitted to the Post-Anesthesia Care Unit. It is rather alarming that the reported prevalence of patients with characteristics suggestive of obstructive sleep apnea (OSA) as evaluated by the STOP-BANG questionnaire was 52% (177 from 340). This number suggests that the majority of patients in the surgical population have undiagnosed OSA; however, it is unfortunate that in this study there was no polysomnography analysis of the patients and so, there was no confirmation of this estimated prevalence. If, however, we report to the study done by Chung et al., author of the STOP and STOP-BANG questionnaires, which was also with a surgical population, we see that the reported percentage of patients with STOP-BANG ≥ 3 is of 57.5% (429 from 746), which is close to the number from the study by Pereira et al. However, in the study by Chung et al., these patients were analyzed with polysomnography and 75.3% of the group with SOTP-BANG score >3 were confirmed to have OSA (43.3% from the total of 746). If we accept that both of these surgical populations, from the study of Pereira et al. and the study of Chung et al., are similar, we can infer that the prevalence of undiagnosed OSA in patients with STOPBANG ≥ 3 in the Pereira et al. study is 39% (177 * 0.75/340), somewhat lower than the reported estimated prevalence of 52%.