Sleep Apnea Diagnosed by Full Polysomnography Is a Factor of Acute Hypoxic Respiratory Failure in Covid-19: A Prospective Clinical-Based Cohort Study

Introduction: COVID-19 is a respiratory disease with clinical manifestation, severity, and outcomes heterogeneity, from asymptomatic presentation to an acute hypoxemic respiratory failure. Clinical characteristics and comorbidities may affect susceptibility to a more severe COVID-19. We hypothesize that obstructive sleep apnea (OSA) may be a significant factor that mitigates COVID-19 severity. Methods: A prospective multicentric cohort "Co-survivors" with a sample size of 400 patients was set and started recruiting in June 2020. Patients with a respiratory presentation of COVID-19 were selected. All severities of COVID-19 were allowed from outpatients to patients requiring prolonged invasive mechanical ventilation. At 3-months follow-up, patients underwent a cardio-respiratory clinical investigation. Initial and actual clinical manifestations and comorbidities were collected. All patients underwent a full polysomnography (PSG) or respiratory polygraphy (PG). Results: At the time of the analysis, 121 patients were included in the cohort. OSA was diagnosed before COVID-19 and already treated in 10 patients, and 23 were waiting for investigation. Full PSG was performed in 88 patients (80 PSG and 8 PG). OSA was absent in 15 (17%) patients, while mild, moderate, and severe OSA was present in 30 (34.1%), 21 (23.9%) and 22 (25%), respectively. Outpatient COVID-19 was reported in 30 (34.1%), hospitalization was needed without and with acute respiratory failure in 13 (14%) and 45 (51%) patients, respectivelly. These later were predominantly male and older, did not exhibit more comorbidity but metabolic characteristics with significant higher body mass index and waist circumference. Sleep recordings revealed an AHI of 7.4 [1.7;15.4], 15.7 [8.3;48.9] and 21.9 [14;35.1] p<0.01 in these three classes of COVID-19 severity, respectively. Finally, undiagnosed OSA was a factor of COVID-19 severity. Conclusions: Patients with OSA are highly represented in a population of COVID-19 survivors. About 10% of the patients were diagnosed prior to infection, undiagnosed moderate or severe OSA was diagnosed in 48.9% of the remaining patents. Moreover, OSA is likely to be a factor of acute respiratory failure in patients infected with SARS-CoV-2.