Head-of-bed elevation outcomes on apnea severity nasal resistance in obstructive sleep apnea: a multicenter observational study

Objectives: OSA has been demonstrated to be significantly influenced by body position, and supine one making the disease severity worse. Head-of-bed elevation (HOBE) is advocated as an easily applicable positional therapy, yet its hemodynamic response is incompletely elucidated. This investigation assessed the influence of HOBE on polysomnographic (PSG) parameters and nasal resistance drives and the pattern of upper airway collapse, compared with healthy controls in OSA patients. Methods: In this prospective multicenter observational study, we enrolled 60 participants (30 OSA patients, 30 controls). All underwent full polysomnography in three positions (supine, 30° HOBE, lateral). We assessed Rhinomanometry and nasal valve outcomes while upper airway collapse was classified using the VOTE system. Primary outcome was change in apnea–hypopnea index (AHI); secondary outcomes included oxygen desaturation index (ODI), minimum oxygen saturation (MinSaO₂), sleep efficiency, and responder rate (≥ 50% AHI reduction in HOBE vs supine). Results: Groups were comparable in age (median 50.0 vs 53.5 years, p = 0.439) and BMI (27.2 vs 27.4 kg/m2, p = 0.321). In OSA patients, AHI decreased significantly from supine to HOBE (25.7 to 17.8 events/hour; mean reduction –31%, p < 0.001), with further improvement in lateral (25.7 to 14.8; p < 0.001). ODI showed a similar reduction (20.3 supine to 15.2 HOBE; p < 0.001). Sleep efficiency improved progressively (73.0% supine, 79.0% HOBE, 83.7% lateral; repeated measures ANOVA p < 0.001, η2p = 0.693). MinSaO₂ also varied significantly by position (p < 0.001, η2p = 0.730). Fifty percent of OSA patients achieved responder status in HOBE, with a four-fold increased odds compared with controls. In addition, we found elevated expiratory resistance in OSA patients (p = 0.013) at Rhinomanometry, which correlated with VOTE-oropharyngeal collapse scores. Conclusions: HOBE represents low-cost, well-tolerated positional therapy as non-CPAP alternative for selected positional OSA phenotypes. A 30° HOBE may significantly improves AHI, ODI, and sleep efficiency in OSA patients while reducing expiratory nasal resistance. Integration with rhinomanometry and endoscopic phenotyping could guide personalized therapy.