How dangerous is sleep apnoea?

Sleep apnoea is a common condition in which breathing repeatedly stops or is severely reduced during sleep. It is estimated to affect nearly one billion people worldwide. In a large Swiss population study, as many as 49.7% of men and 23.4% of women had a moderate to severe form. Yet in many cases the condition goes unrecognised or untreated (PMID 39242062, 32436658, 25682233).

The risks to the heart and blood vessels are the most well-documented. Moderate to severe sleep apnoea (more than 15 breathing pauses per hour) significantly raises the risk of coronary artery disease, heart failure, stroke and cardiac arrhythmias, and also increases the likelihood of serious complications and death from those conditions (PMID 39242062). Another study found that people with sleep apnoea had nearly twice the chance of stroke or death, even after adjusting for known risk factors such as smoking, diabetes and high blood pressure (hazard ratio 1.97; PMID 16282178).

Beyond cardiovascular disease, sleep apnoea is linked to a broader range of health problems. In a large population study, people with the most severe forms of sleep apnoea had an increased likelihood of high blood pressure (60% higher), diabetes (twice as high), metabolic syndrome (2.8 times as high) and depression (nearly twice as high), independently of other factors (PMID 25682233).

There is a particularly high-risk group: people who have both sleep apnoea and insomnia, a combination known as 'COMISA'. Over a 15-year follow-up period, they had a 47% higher risk of death compared with people who had neither condition (hazard ratio 1.47). Notably, sleep apnoea or insomnia alone did not produce a significantly elevated mortality rate in this study, indicating that the combination is especially dangerous (PMID 34857613).

There is also observational evidence that people with osteoarthritis of the knee, hip or hand have an approximately 45 to 50% higher risk of developing sleep apnoea. This association has not yet been proven to be causal (PMID 40329131).

There is good news: treatment with a CPAP device, a mask that keeps the airways open during the night, improves sleep quality, lowers blood pressure, reduces cardiac arrhythmias and relieves excessive daytime sleepiness. This effect occurs with adequate use, meaning at least four hours per night on more than 70% of nights (PMID 39242062). Left untreated, sleep apnoea poses a considerable threat to both individual health and public health worldwide (PMID 32436658, 29779616).