Role of bronchial hyperresponsiveness in patients with obstructive sleep apnea with asthma-like symptoms

Background: Obstructive sleep apnea (OSA) is one of the major co -morbidities and aggravating factors of asthma. In OSA-complicated asthma, obesity, visceral fat, and systemic in flammation are associated with its severity, but the role of bronchial hyperresponsiveness (BHR) is unclear. We investigated the involvement of BHR and mediastinal fat width, as a measure of visceral fat, with OSA severity in patients with OSA and asthma -like symptoms. Methods: Patients with OSA who underwent BHR test and chest computed tomography scan for asthmalike symptoms were retrospectively enrolled. We evaluated the relationship between apnea-hypopnea index (AHI) and PC 20 or anterior mediastinal fat width, strati fied by the presence or absence of BHR. Results: OSA patients with BHR (n = 29) showed more obstructive airways and frequent low arousal threshold and lower mediastinal fat width, and tended to show fewer AHI than those without BHR (n = 25). In the overall analysis, mediastinal fat width was signi ficantly positively correlated with AHI, which was signi ficant even after adjustment with age and gender. This was especially signi ficant in patients without BHR, while in OSA patients with BHR, there were signi ficant negative associations between apnea index and air flow limitation, and hypopnea index and PC 20 . Conclusions: Risk factors for greater AHI differed depending on the presence or absence of BHR in OSA patients with asthma -like symptoms. In the presence of BHR, severity of asthma may determine the severity of concomitant OSA. (c) 2023 Japanese Society of Allergology. Published by Elsevier B.V. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).