A large Australian study has discovered that medical intervention for obstructive sleep apnea (OSA) can improve depression symptoms in patients suffering from cardiovascular diseases. The study is by far the largest trial of its type and one of very few studies reporting such an effect.

Using data from the Sleep Apnea Cardiovascular Endpoints (SAVE) trial led by Flinders University, researchers discovered treatment via continuous positive airway pressure (CPAP) for moderate-severe OSA among patients with cardiovascular disease has broad benefits in terms of preventing depression, independent of improved sleepiness.

The SAVE trial participants were recruited from more than 80 clinical centers in China, Australia, New Zealand, India, the USA, Spain and Brazil. Participants were predominantly overweight and older males, habitual snorers and had moderately severe OSA. Specific findings include:

  • the positive effect of CPAP treatment on depression symptoms was manifest within six months and persisted during the 3.7 years of follow-up;
  • the positive effect of CPAP treatment on depression symptoms was more pronounced in patients with lower mood scores prior to treatment.

Prior studies investigating the effect of CPAP on mood with various experimental designs and length of follow-up periods have yielded mixed results.

“Patients who have had a stroke or heart attack are prone to suffer from low mood and are 2 to 3 times more likely to develop clinical depression, which then further elevates their risk of future heart attacks and strokes,” said SAVE principal investigator and senior author Professor Doug McEvoy.

The study appears in The Lancet EClinicalMedicine.

With up to 50 percent of patients with CV disease likely to have OSA, the study is “welcome news that treatment of OSA substantially relieves cardiovascular patients’ depressive symptoms and improves their wellbeing.”

The paper’s first author, Dr. Danni Zheng, from the George Institute for Global Health (UNSW), said the 2687 OSA patients enrolled in the SAVE trial were based solely on their history of cardiovascular disease and not on their current mood status.

“After following them for an average of 3.7 years, we found that CPAP provided significant reductions in depression symptoms compared with those who were not treated for OSA. The improvement for depression was apparent within six months and was sustained.”

As expected, those with lower mood scores to start with appeared to get the greatest benefit.

“Our additional systematic review which combined the SAVE study findings with previous work provided further support of the treatment effect of CPAP for depression,” Zheng said.

Source: Flinders University/EurekAlert