According to a study in the October issue of Anesthesiology, the official medical journal of the American Society of Anesthesiologists, patients with obstructive sleep apnea (OSA) who are diagnosed and treated for the condition prior to surgery are less likely to develop serious cardiovascular complications such as cardiac arrest or shock.

“OSA is a common disorder that affects millions and is associated with an increased risk of surgical complications, but the condition often goes unrecognized,” says Thomas Mutter, MD, lead author, department of anesthesia and perioperative medicine, University of Manitoba, Winnipeg, Canada, in a release. “As many as 25% of surgical patients may have OSA, but the vast majority of these patients aren’t treated or don’t know they have the disorder.”

The study compared postoperative outcomes in 4,211 patients with OSA, who were diagnosed by sleep study either before or after surgery, with a matched control group of patients who did not have the condition. Those who were diagnosed with OSA prior to surgery were prescribed treatment with CPAP therapy.

The study found that although patients with untreated OSA were at an increased risk of developing cardiovascular complications, patients who were diagnosed and treated with CPAP therapy before surgery were less than half as likely to experience cardiovascular complications such as cardiac arrest or shock.

Additionally, researchers found that respiratory complications were twice as likely to occur in patients with OSA, compared to patients without the condition, regardless of when patients were diagnosed or if CPAP therapy was prescribed.

For both cardiovascular and respiratory complications, increasing severity of OSA was associated with increased risk. Age, type of surgery, and other diseases were also important risk factors.

The authors acknowledge limitations related to their retrospective study, as well as the potential resources needed to implement widespread screening. Nonetheless, this study adds to the knowledge base of how to care for this increasingly large segment of the population.