Factors Associated with the Severity of Obstructive Sleep Apnea: Risk Factors and Screening with the Epworth Sleepiness Scale and STOP-Bang Questionnaire

Abstract

            Obstructive sleep apnea (OSA) is a common public health problem associated with cardiovascular complications. However, standard screening tools such as the Epworth Sleepiness Scale (ESS) and STOP-Bang Questionnaire were primarily developed to detect the presence of OSA rather than to discriminate disease severity. This study therefore aimed to identify factors associated with the severity of OSA, based on risk factors and screening scores from the ESS and STOP-Bang Questionnaire. A retrospective cross-sectional analytical study was conducted among 72 patients aged 20-80 years who were diagnosed with OSA by polysomnography at Pakchongnana Hospital between June 2024 and July 2025. Data were analyzed using multivariable logistic regression, with multicollinearity assessed via variance inflation factor before model construction.

            The sample comprised 34 patients with severe OSA and 38 with mild-moderate OSA. After mutual adjustment, neck circumference was significantly associated with disease severity (adjusted OR 1.18, 95% CI 1.03, 1.35). Male sex showed a trend toward association, with an adjusted OR of 2.58 (95% CI 0.92, 7.23); this association did not reach statistical significance, p=0.071. Neither ESS nor STOP-Bang scores were statistically associated with disease severity; the STOP-Bang score was excluded from the model due to an elevated VIF reflecting multicollinearity with its component variables.

            The findings indicate that standard screening tools cannot discriminate OSA severity among patients with a confirmed diagnosis, whereas neck circumference, a simple and cost-free measurement, may offer additional value in prioritizing patients for urgent polysomnography referral, particularly in resource-limited settings. Further validation studies in larger samples are warranted before wider clinical application.