Among patients with COVID-19, older age, minority ethnicity, obesity, hypertension and diabetes have all been associated with increased morbidity and mortality. Sleep apnea, a condition characterized by disrupted breathing during sleep, is common among older, obese and minority populations, but its association with COVID-19 outcomes has largely remained unexplored. Brigham researchers and collaborators examined electronic health record data of 4,668 COVID-19 patients from Mass General Brigham, 443 of whom had sleep apnea, and found a significant association between sleep apnea and COVID-19 morbidity and mortality. Findings were published in the American Journal of Respiratory and Critical Care Medicine.
The mortality rate for those with sleep apnea was 11.7 percent, compared with a mortality rate of 6.9 percent among those without sleep apnea.
“We know that there are lung effects associated with sleep apnea,” said Brian Cade, PhD, of the Division of Sleep and Circadian Disorders at the Brigham, who is the first author on the paper. “Sleep apnea might be a hidden factor that explains a portion of the morbidity and mortality we see associated with known factors, such as diabetes and hypertension.”
The findings also suggested potentially greater adverse outcomes for COVID-19 patients whose sleep apnea had not been treated with continuous positive airway pressure (CPAP) in the past year. When the researchers compared the outcomes of those with and without evidence of recent CPAP use, they observed higher levels of mortality, mechanical ventilation, and intensive care unit hospitalization in the untreated group, after accounting for differences in age, sex, race, and six additional risk factors for COVID-19.
In contrast, the odds of adverse outcomes were roughly the same between those without sleep apnea and those with CPAP-treated sleep apnea.
“This study highlights the possibility that untreated sleep apnea may contribute to poor outcomes in those with COVID-19,” said Michael Twery, PhD, director of the National Center on Sleep Disorders Research of the National Heart, Lung, and Blood Institute, part of the National Institutes of Health and one of the study’s funders. “More studies are needed to explore how difficulty breathing during sleep may be a factor and whether recognizing sleep apnea in patients could influence COVID-19 risks, particularly in minority populations and other groups at highest risk for sleep apnea.”
The researchers caution that a greater sample size is needed to state that untreated sleep apnea is truly a risk factor for COVID-19; however, it appears as if the untreated group’s outcomes are driving the observed increase in adverse outcomes overall. The team plans to resolve the limitations of the current study with a future, two-fold increase in the sample size.
Cade states that the researchers had not known whether they would see increased morbidity among sleep apnea patients who have used CPAP, which pushes air into the throat and lungs.
“It’s challenging for patients,” Cade said. “It could very well be that this force leads to damage in the lungs that might increase your risk for COVID-19. But with our current data, it seems like using CPAP is protective.”
This study was supported by grants from the National Institutes of Health (K01HL135405, R35HL135818, and U01HG008685).
Paper cited: Cade, BE et al. “Sleep Apnea and COVID-19 Mortality and Hospitalization” American Journal of Respiratory and Critical Care Medicine DOI: 10.1164/rccm.202006-2252LE
