Obstructive sleep apnoeahypopnoea increases risk of heart attacks

Men with a severe form of a sleep breathing disorder called obstructive sleep apnoeahypopnoea have an increased risk of fatal and non-fatal cardiovascular events, concludes a study published in this week’s issue of The Lancet.

Obstructive sleep apnoea-hypopnoea affects four per cent of middle-aged men and two per cent of middle-aged women. It is caused by a blockage in the pharynx that obstructs airflow during sleep. Individuals with the condition regularly stop breathing during sleep for 10 seconds or longer (apnoea) and have slowed breathing (hypopnoea). It is associated with high rates of illness and mortality. Previous studies have linked it with an increased risk of cardiovascular disease but these have not taken into account potential confounding factors. After adjustment for age and obesity such studies have not been able to show an increased risk.

Jose Marin (Hospital Universitario Miguel Servet, Spain) and colleagues recruited 264 healthy men matched for age and body mass index, 377 simple snorers, 403 with untreated severe disease and 372 with the disease and treated with continuous positive airway pressure (CPAP). Participants were followed-up at least once a year for an average of 10 years. Patients with untreated severe disease had a higher incidence of fatal cardiovascular events (1·06 per 100 person-years) and non-fatal cardiovascular events (2·13 per 100 person-years) than untreated patients with mild-moderate disease, simple snorers, patients treated with CPAP and healthy participants— even after adjustment for potential confounding factors.

Dr Marin concludes: “The results of this large, long-term, prospective controlled study suggest that in untreated men with severe obstructive sleep apnoea-hypopnoea, the risk of fatal and non-fatal cardiovascular events is increased. There is a relation between the severity of this disease and cardiovascular risk, but effective treatment with nasal CPAP significantly reduces the cardiovascular outcomes associated with this medical condition. Simple snoring is not a significant cardiovascular risk factor.”