Obstructive sleep apnea (OSA) and asthma are closely related. Recent data indicates that asthma is a risk factor for OSA and OSA has been linked to poor asthma outcomes. A harmful and vicious cycle is perpetuated if OSA is not aggressively addressed.
OSA and asthma share many risk factors for their respective diseases. The risk factors include obesity, gastrointestinal reflux, and chronic rhinitis, but some of the characteristic features of asthma, such as airway inflammation as well as systemic inflammation, have an impact on the risk of OSA. We are just starting to understand the effects that OSA has on asthma. These risk factors include chronic intermittent reductions in oxygen levels, increased work of breathing, and sleep fragmentation.
In the last decade, despite extensive research, the morbidity and mortality for asthma has remained unchanged. The relationship between asthma and the presence of OSA suggests that this interaction begins very early in life, perhaps even while the fetus is developing. This relationship may, in part, be explained by recognizing that the upper airways, which are the focus of OSA, and the lower airways involved with asthma, are linked and that much of the inflammation associated with asthma and the upper airway obstruction noted in OSA, combine to affect each other adversely.
What does this mean for evaluations and treatments? It means that physicians should consider screening their asthma patients for OSA, particularly if asthma has been long-standing, difficult to control, or requires higher doses of inhaled steroids.