Complicating effects of obstructive sleep apnea syndrome on the severity of adult asthma

Introduction: Bronchial asthma (BA) and obstructive sleep apnea syndrome (OSAS) are common causes of respiratory disturbance. Many cases of patients with both conditions have been reported, and BA and OSAS may exacerbate each other, but information remains sparse.Methods:We retrospectively evaluated 60 patients under treatment for BA in our department between April 2016 and March 2018 who also underwent portable polysomnography (PSG) for suspected OSAS to assess potential association between PSG results and asthma treatment or respiratory function. BA was diagnosed and treated according to the Asthma Prevention and Management Guideline 2015.Results: We found that BA treatment intensity step was significantly higher for patients with BA who had concurrent moderate or severe OSAS (p = 0.0016). However, neither respiratory function, fraction of exhaled nitric oxide (FeNO), nor forced oscillation technique (FOT) differed significantly between patients with and without OSAS, and apnea hypopnea index was not significantly correlated with respiratory function, FeNO or FOT parameters.Conclusion:We conclude that even though BA patients with OSAS had good respiratory function, their BA was more severe than that of patients without OSAS, suggesting that OSAS may exacerbate BA. Background factors and asthma parameters were not predictive of PSG results, and patients with suspected OSAS should be evaluated proactively by using PSG.