Obstructive sleep apnea is a determinant of asthma control independent of smoking, reflux, and rhinitis.

Background

Asthma control is defined as to what extent manifestations of asthma can be observed in a patient or have been reduced or removed by treatment. Regular use of asthma treatments, correct inhaler technique, adequate information provided about the patient's diseases and medicines, and patient-clinician collaboration aid asthma control. Asthma shares risk factors and links in the pathogenesis with obstructive sleep apnea (OSA), and OSA may aggravate asthma symptoms.

Objective

To assess the risk of OSA for asthma control.

Methods

The study was carried out in subjects with asthma who were followed up at specific time points and who used asthma medication regularly and with an appropriate inhaler technique. An asthma control test and a questionnaire were used to determine the asthma control levels and OSA risk of the subjects.

Results

With regard to the questionnaire scoring, 77 of 137 subjects with asthma had a low OSA risk and 60 had a high OSA risk. The proportion of the subjects with a high OSA risk (p < 0.001) and were smokers (p = 0.020) were significantly higher in the subjects with uncontrolled asthma than in those with controlled asthma. Logistic regression analysis showed that the variables that affect asthma control status were the risk of OSA and obesity. The subjects with a low OSA risk were more likely to have controlled asthma than those with a high OSA risk (odds ratio 7.896 [95% confidence interval, 2.902-21.487]; p < 0.001).

Conclusion

In the subjects with asthma and who adhered to therapy and used inhalers with the correct technique, a high risk of OSA was associated with poor control of their asthma. This association was independent of other factors, including rhinitis, gastroesophageal reflux, and smoking.