Predictors of swallowing disorders in Obstructive Sleep Apnea Syndrome: a case-control and cross-sectional study

Introduction: Obstructive sleep apnea syndrome (OSAS) is a prevalent sleep disorder characterized by recurrent upper airway collapse, leading to intermittent hypoxia and sleep fragmentation. While OSAS is associated with multiple systemic comorbidities, its impact on swallowing function remains underrecognized. This study aims to compare swallowing characteristics between OSAS patients and controls and identify risk factors and predictors of swallowing disorders severity. Methods: A case-control and cross-sectional study was conducted with people with moderate to severe OSAS (PwOSAS) and age- and sex-matched controls. Swallowing function was assessed using the Fiberoptic Endoscopic Evaluation of Swallowing, Dysphagia Outcome and Severity Scale (DOSS), and Dysphagia Handicap Index (DHI). Descriptive statistics, normality tests, group comparisons (t-test, Mann-Whitney U test, Chi-square, Fisher’s exact test) and an ordinal regression were applied, with significance set at p ≤ 0.05. Results: Fifty individuals (PwOSAS n = 25 and controls n = 25) were included, with a mean age of 50 ± 1.55 years. Swallowing impairments were identified in 60% of PwOSAS compared to 28% of controls (p = 0.023). The most frequent impairments were pharyngeal residue accumulation (52% in PwOSAS vs. 24% in controls; p = 0.041), followed by premature spillage (12% vs. 4%; p = 0.297). PwOSAS had significantly higher DHI scores than controls (p = 0.024). The percentage of recording time with SpO₂ below 90% (T90) is a negative predictor of the severity of swallowing disorders. Conclusion: Swallowing impairments are common in PwOSAS, with significantly higher pharyngeal residue accumulation and greater impact on daily life compared to controls. These findings highlight the importance of swallowing assessment in this population.