Sleep Apnea Increases Risk of Worse COVID Outcomes
Researchers next wanted to determine whether sleep apnea increased the risk of worse outcomes from COVID-19. They tested this in two different ways.
First, they compared the amount of time a person spent with blood oxygen saturation below 90% to the numerical classification scale for COVID outcomes designed by the World Health Organization (WHO). They found that higher time spent with low oxygen was associated with a 39% higher risk of poor COVID outcomes.
To strengthen their results, researchers then compared the amount of time spent with low oxygen to the risk of hospitalization and/or death from COVID. They found that people who spent more than 1.8% of their sleep time with less than 90% oxygen saturation (about 8½ minutes out of 8 hours’ sleep) were 31% more likely to be hospitalized or die from COVID. More time spent with low oxygen increased the risk further.
These risks remained even after accounting for potential confounding factors like obesity, cardiopulmonary disease, cancer, and smoking. This makes researchers conclude that low oxygen saturation associated with sleep apnea is an independent predictor of worse COVID outcomes.
After looking at potential reasons why sleep apnea might lead to worse COVID outcomes, researchers concluded that systemic inflammation, including elevated levels of C-reactive protein (CRP) levels, was most consistent with their results.