This graph is of patients who have severe sleep apnea. You can see there are four lines. The top line, which is labeled Control, is the group of patients which were considered to have sleep apnea that did not require treatment. Sleep apnea is measured by the Apnea Hypopnea Index, and it’s considered that lesson five is not necessarily requiring treatment unless there’s symptoms and other reasons.
So the next three lines are compared to that.
The significance here is that the patients who were untreated, 20% of them approximately had died after eight years since diagnosis, and that the CPAP and Mandibular Advancement Splint group had a similar survival curve. So the significance is, that all the patients that did die actually died of a cardiovascular event, so they had a heart attack or a stroke, and we know that the risk of passing away from a heart attack or a stroke is increased in cases of severe sleep apnea. You might also note that the solid line, the control line follows a very similar path to the CPAP, which is the mask that pumps air down you all night and the Mandibular Advancement Splint.
Therefore, we think the chances of surviving if you have less than five events per hour, or if you are treated with CPAP or Mandibular Advancement Splint is approximately the same.
The group we get concerned about are this untreated group. Now the untreated group also includes the undiagnosed group, although not shown in this study. So in a population study, we would expect that people who have a high risk of having severe sleep apnea or indeed significant sleep apnea should be treated for their risk of dying from a cardiovascular event is significantly increased.