Obstructive sleep apnoea increases risk of CVD.

In OSA, the patient suffers repeated episodes of apnoea caused by narrowing or closure of the pharyngeal airway during sleep. The degree of closure of the airway leads to periods of either apnoea (complete) or hypopnoea (partial) obstruction. Population-based surveys estimate that 2-4% of the middle-aged population have OSA, which is similar to the prevalence of diabetes and asthma. Although understanding of the condition has improved considerably, it is estimated that 85-90% of sufferers still remain undiagnosed. OSA is not only a cause of excessive daytime somnolence leading to an increased risk of accidents on the road and poor work performance, but also a major cause of social dysfunction, reduced quality of life related to poor health, and mood disorders. Untreated OSA predicts a substantially increased risk of hypertension, cardiovascular disease, cerebrovascular disease, depression, and mortality. Wherever OSA is considered, the following questions should be asked: Is this patient falling asleep regularly against their will? Is this patient often sleepy while driving? Is this patient experiencing difficulty at work because of excessive sleepiness? Is sleep refreshing? Is surgery for snoring being considered (OSA should be excluded first)? The gold standard for investigation of OSA is polysomnography. It is possible to diagnose almost 90% of OSA patients from limited sleep studies often conducted on a domiciliary basis with portable diagnostic equipment.