Chronic obstructive pulmonary disease and obstructive sleep apnoea overlap: co-existence, co-morbidity, or causality?

The chronic obstructive pulmonary disease and obstructive sleep apnoea overlap syndrome is associated with higher morbidity and mortality rates than either disease alone. There is evidence of a bidirectional relationship between the two conditions, with the overlap syndrome encompassing a spectrum of clinical phenotypes.

This review examines the evidence for the various factors that determine the overlap syndrome, the impact overlap syndrome has on co-morbidities, and implications for diagnosis and treatment.

The accurate diagnosis of the overlap syndrome is critical given its implications for treatment optimisation and reduction in healthcare utilisation and costs.