Concurrence of Chronic Obstructive Pulmonary Disease and Sleep Apnoea: The Other Overlap Syndrome

Obstructive sleep apnoea and chronic obstructive pulmonary disease (COPD), each a prevalent and clinically important condition in adults, carry numerous common risk factors, including obesity and smoking. It is estimated that the coexistence of obstructive sleep apnoea and COPD, the COPD/obstructive sleep apnoea overlap syndrome, affects more than 1% of the general population. The presence of such overlap, when obstructive sleep apnoea is untreated, carries a risk of more adverse diurnal and nocturnal physiological and clinical outcomes, including greater sleep fragmentation, more severe nocturnal hypoxaemia, and increased overall mortality than is documented for COPD alone and obstructive sleep apnoea alone. Effective identification and treatment of the comorbid obstructive sleep apnoea and the other features of sleep-disordered breathing in the COPD/obstructive sleep apnoea overlap syndrome improve overall clinical outcomes in the condition.