In this episode we delve into the SAVE study which was THE landmark trial that investigated whether using CPAP (Continuous Positive Airway Pressure) to treat Obstructive Sleep Apnoea (OSA) also improved cardiovascular disease. The trial also assessed the impact of CPAP on quality of life.
The study randomised 2,687 patients to either receive CPAP or not. These patients were at very high risk of cardiovascular disease, having a previous history of stroke or myocardial infarction. They all underwent an overnight sleep study in a core sleep laboratory and all had to have moderate to severe sleep apnoea. Those who were dangerously sleepy, with an Epworth Sleepiness Scale of greater than 15, were excluded.
After and average of 3.7 years they found no difference in cardiovascular disease between those getting CPAP versus those who did not. 15.4% of those not getting CPAP developed cardiovascular disease versus 17% of those who did get CPAP. This was not statistically significant but it was favouring those who did not get CPAP.
There was an improvement in sleepiness in the CPAP group, with an average reduction of 2.5 points on the 24 point Epworth Sleepiness Scale. There was also a slight reduction in anxiety and depression scores, but the average change was not clinically significant.
So what’s the bottom line? In patients who have obstructive sleep apnoea, and are not severely sleepy, as defined by an Epworth sleepiness scale score of 15 or less, CPAP will marginally improve sleepiness but have no impact on their cardiovascular disease.
In this episode we also discuss associations versus causations, appropriate participant numbers for cardiovascular trials and Star Wars?…yep….Star Wars!
The trial was published in NEJM in September 2016 and can be found here: http://www.nejm.org/doi/full/10.1056/NEJMoa1606599#t=article
Music by Polyrhythmics, song title El Fuego