Sleep apnea and fatal cardiac events

Sleep apnea messes with quality of life. It leaves some individuals feeling sluggish, irritable, and maybe even depressed. What’s more, there are physical issues associated with untreated sleep apnea. For example, cardiovascular issues, diabetes, and even skin abnormalities tend to be worsened by apnea. But do these consequences of sleep apnea really matter? In the end, sleep apnea doesn’t kill you. Or might it?

This issue has been investigated in the past, but not to a large enough extent. After all, if you are going to claim something can kill you, you better be pretty sure about it. For that reason, a “meta-analysis,” which is a large analysis that combines many smaller analyses, was conducted. Overall, over 4000 participants were included in the analysis, and the research team divided participants into groups with mild sleep apnea (10-20 apneas/hypopneas per hour) and moderate-to-severe sleep apnea (more than 10 apneas/hypopneas per hour). The research team was interested in seeing whether more severe sleep apnea led to cardiovascular fatal events (death) and non-fatal events (myocardial infarction, stroke, coronary artery bypass surgery, and coronary angiography) and how CPAP (continuous positive airway pressure – the gold standard sleep apnea treatment) affected cardiovascular outcomes. 

First, non-fatal cardiovascular events were examined. When comparing non-treated sleep apneics with CPAP-treated apneics, it was found that CPAP reduced the risk of non-fatal events by 43%. Next, when assessing fatal events, results showed the risk of cardiovascular death was about 68% less for the CPAP-treated individuals. For those with moderate-to-severe sleep apnea, CPAP reduced the risk of cardiovascular death by 71%.

So what’s the deal? How does untreated sleep apnea increase the risk of death? Sleep apnea brings with it many detrimental aspects: lack of oxygen to the brain of body comes with apneas and hypopneas, frequent awakenings occur during or after reduced breathing, and blood pressure swings occur all along the way. These factors, along with exacerbated diabetes, contribute to cardiovascular events. More severe sleep apnea may lead to more severe events (i.e., the ones that kill you), and untreated apnea following an event will hinder recovery. 

Wang, J., Yu, W., Gao, M., Zhang, F., Li, Q., Gu, C., ... & Wei, Y. (2015). Continuous positive airway pressure treatment reduces cardiovascular death and non-fatal cardiovascular events in patients with obstructive sleep apnea: A meta-analysis of 11 studies. International journal of cardiology, 191, 128.


Janna Mantua

Author

Janna is a PhD Student / Graduate Research Assistant at University of Massachusetts Amherst with a background in clinical sleep research and psychology. Janna Mantua is a PhD student in the Behavioral Neuroscience department at the University of Massachusetts. Her research focuses on sleep and aging, with specific projects on cognitive health, inflammation, memory formation, and neuroimaging. Prior to her PhD work, Janna was involved in research on sleep apnea and cognitive decline at the NYU Sleep Disorders Center.



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