OSA Endotyping as Targets for Treatment. How Far Have We Come?

: Obstructive sleep apnoea (OSA) is highly prevalent and is associated with significant impairments in quality of life and comorbidity. The most common treatment employed is continuous positive airway pressure (CPAP), especially in moderate and severe cases. The fundamental pathophysiology of the disorder relates to increased collapsibility of the oropharyngeal airway, but the growing recognition that multiple endotypic factors contribute to this collapsibility has opened the possibility of alternative treatment possibilities, especially in less severe cases. In addition to the most important endotype of upper airway narrowing, additional non-anatomical endotypes include upper airway muscle responsiveness, loop gain, and the arousal threshold. Recent reports have identified mechanisms to identify these endotypes, including those suitable for application in clinical practice. These developments have encouraged a focus on non-CPAP therapies, including oral appliances, pharmacotherapy, and neurostimulation. Recent reports have identified effective pharmacotherapies directed at each non-anatomical endotype. While CPAP is likely to remain the most important and widely used therapy for moderate and severe OSA in the foreseeable future, alternative therapies targeting specific endotypes, especially pharmacotherapy, are likely to play an increasing role in less severe cases in the medium term, and in patients who do not comply with CPAP.