Millions of people in the United States suffer from obstructive sleep apnea, a condition that causes those afflicted to briefly stop breathing during sleep, sometimes several times at night. The disorder, which happens when the throat muscles relax during sleep and block the airway, has been linked to a range of health problems including high blood pressure, heart disease, stroke and type 2 diabetes.

The standard treatment given to patients with the condition is continuous positive airway pressure (CPAP) therapy, which makes use of a machine. The CPAP machine works by pumping a stream of air through the nostril of the patient during sleep to keep the airway open.

There are drawbacks with this therapy, one of which is non-compliance. Many people give up on using the machine because they find the air mask and hose uncomfortable.

Some users bear with the discomfort because the therapy is believed to reduce potentially fatal health risks associated with the condition. A new study, however, challenges this idea.

The Sleep Apnea Cardiovascular Endpoints (SAVE) study found that CPAP does not prevent heart attacks, strokes, hospitalizations or deaths in sleep apnea sufferers with existing cardiovascular disease.

Craig Anderson, from the George Institute for Global Health in Sydney, and colleagues monitored sleep apnea patients with pre-existing vascular disease over a period of four years in 89 hospitals to determine if the use of the CPAP machine would prevent major cardiovascular events such as stroke and heart attack.

Earlier studies suggest that CPAP has a positive impact on these health problems but the result of the study, which is by far the largest to look into the condition and involved 2,687 participants, revealed otherwise.

The findings revealed that although the use of the CPAP machine reduces daytime sleepiness plaguing sleep apnea patients — reducing anxiety and depression and boosting mood and work productivity — the use of the CPAP machine does not appear to be helpful in reducing risk of heart attack and stroke in sleep apnea sufferers.

In patients under the CPAP group, the rate of cardiovascular events was 17 percent, while the rate in the control group was 15.4 percent.

"At the moment, we could not recommend, on the basis of our study findings, that CPAP be used for the prevention of cardiovascular disease in patients, particularly those who are asymptomatic from sleep apnea," said study lead Dr. Doug McEvoy from the Adelaide Institute for Sleep Health.

The research was presented at a cardiology conference held in Rome, Italy on Sunday, Aug. 28 and published in the New England Journal of Medicine.