Patients with coronavirus-2019 (COVID-19) and obstructive sleep apnea (OSA) may be at increased risk for mortality, according to results from a systematic review, published in Sleep Medicine Reviews.
Publication databases were searched through June 2, 2020 for papers which included data on COVID-19 combined with data on sleep phenotypes or disorders. A total of 18 studies were included.
These included studies found that the comorbidities that have been reported to be associated with poorer COVID-19 outcomes (eg, diabetes, hypertension, lung diseases, and cardiovascular diseases) were at higher instance rates among patients with OSA.
Of the included studies, 2 found that more than 20% of patients in the intensive care unit for COVID-19 had OSA and 1 study found an enrichment for OSA among those treated in the intensive care unit compared with general hospitalization (8.3% vs 6.3%). A study observed that individuals with OSA and diabetes had an increased risk for death on day 7 (odds ratio [OR], 2.80; 95% CI, 1.46-5.38).
Two possible molecular mechanisms were identified for why patients with OSA had worse COVID-19 outcomes. Patients with OSA have increased inflammatory markers. This phenotype may contribute to a cytokine storm, which has been observed among the most severe COVID-19 cases.
Individuals with OSA often have comorbid resistant hypertension, which may be in part caused by increased blood pressure through the stimulation of the renin-angiotensin-aldosterone system (RAAS). A gene in the RAAS network has been found to be an entry receptor for this particular coronavirus. Further study is needed to determine whether the elevated stimulation of RAAS may contribute to poorer COVID-19 outcomes.
The common treatment for OSA is non-invasive ventilation like continuous positive airway pressure (CPAP). TCPAP is an aerosol-generating procedure, putting individuals in the vicinity at high risk for viral exposure and leading 1 of the included studies to recommend cessation of CPAP, if possible, during the pandemic. The guidelines published by the British Sleep Society and the OSA Alliance recommended that patients should continue CPAP therapy, but to distance themselves from others while using it.
A general decline for new OSA diagnoses was observed, stating that patients had difficulty traveling, or that centers had reduced visitation. Concerns over sanitation of equipment used during sleep studies were commonly reported, and the Center for Disease Control and Prevention released guidelines which stated that reusable laboratory equipment should be removed from service for a minimum of 72 hours between patients, greatly reducing the number of patients that could be analyzed at sleep clinics.
The major limitation of this study was the combination of many differing study types, which highlighted the fact that there was little consensus around the global pandemic.
These data indicated that individuals with OSA were likely at increased risk for poorer clinical outcomes from COVID-19 due to the increased rates of comorbidities among this patient population and that a systemic decline in diagnosis was occurring. Further study is needed to better relate the underlying molecular mechanisms which increase COVID-19 mortality risk.
Miller MA and Cappucio FP. A systematic review of COVID-19 and obstructive sleep apnoea. Sleep Med Rev. 2020;55:101382. doi: 10.1016/j.smrv.2020.101382