Comorbid obstructive sleep apnoea and chronic obstructive pulmonary disease and the risk of cardiovascular disease

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnoea (OSA) syndrome are each highly prevalent with recent population-based studies indicating that about 10% of the general adult population have one or other disorder (1,2). However, the prevalence of isolated sleep disordered breathing (SDB) as measured by the frequency of apnoeas or hypopnoeas per hour of sleep [apnoea-hypopnoea index (AHI)] without accompanying symptoms such as sleepiness is considerably higher with recent studies indicating that up to 50% of adult males have significantly elevated AHI (3), and even higher numbers in the elderly. Based on these prevalence figures, up to half of patients with COPD will likely have at least some degree of SDB based on chance association alone. Furthermore, COPD alone is associated with sleep disturbance (4), which can result in significant negative effects on quality of life (5)