Modified STOP-bang questionnaire incorporating morning dry mouth and BMI adjustment in China: a retrospective study of 590 patients

Background: Morning dry mouth (MDM) is a common symptom of Obstructive Sleep Apnea (OSA) yet current OSA screening tools overlook it.Objective: To enhance the specificity of the Stop-Bang questionnaire (SBQ) by adding an MDM symptom.Method: A retrospective analysis on 590 patients from Peking University First Hospital (2013-2018) suspected of OSA was conducted. They underwent polysomnography. The research incorporated the MDM symptom into SBQ and adjusted the body mass index (BMI) threshold to 28 kg/m(2). Predictive parameters were then calculated.Results: 83.1% patients were diagnosed with OSA, with 61.4% reporting MDM. Multivariate regression confirmed MDM significantly influenced Apnea-Hypopnea Index (AHI). Adjusted SBQ with MDM showed a slight decrease in sensitivity but improved specificity, especially when using a BMI threshold of > 28 kg/m(2). For AHI >= 5 events/h and AHI >= 15 events/h, adjusted SBQ with MDM (BMI >28 kg/m(2)) obtained the highest Youden index.Conclusion: Incorporating the MDM symptom into SBQ and adjusting the BMI threshold enhances the diagnostic specificity for OSA.