Obstructive sleep apnea (OSA) and other sleep disorders often accompany the chronic health conditions (e.g. cardiovascular disease, diabetes, chronic lung disease) known to increase the risk for poor outcomes after SARS-CoV-2 infection. However, little was known about how many patients hospitalized with COVID-19 had pre-existing sleep disorders, and if having a sleep disorder would worsen the COVID-19 disease course. A research team led by sleep researchers Helen Burgess and Cathy Goldstein and biostatistician Jonathan Troost, investigated this and results of the study have recently been published in the Journal of Clinical Sleep Medicine.
This study included 572 adults hospitalized for COVID-19 in the University of Michigan Hospital System between March 9 and November 4, 2020. The patients were followed for at least 121 days after hospital admission. A review of diagnostic codes in the electronic medical record in the two years prior to hospital admission revealed that 207 patients had a pre-existing sleep disorder (20% OSA, 11% insomnia, 4% restless leg syndrome or periodic limb movements, 1% central sleep apnea, 1% hypoventilation). A smaller subset of 73 patients had completed a diagnostic sleep study at the University of Michigan Sleep Disorders Center before their SARS-CoV-2 infection, which allowed the authors to evaluate whether the severity of sleep apnea was associated with outcomes.
After the effects of age, sex, body mass index and race of the patients was considered, pre-existing sleep disorders did not increase the need for mechanical ventilators or vasopressors (medications that increase blood pressure) during hospitalization, length of hospital stay or risk of death. Variables derived from the diagnostic sleep studies, including the minimum oxygen saturation level, and number of apneas/hyponeas (breathing interruptions) per hour, were also not significantly related to adverse outcomes in patients hospitalized for COVD-19.
Overall the study showed that sleep disorders are relatively common in patients hospitalized with COVID-19, but once hospitalized, pre-existing sleep disorders did not worsen treatment outcomes. In future work, the team will investigate if pre-existing sleep disorders increase the risk of becoming infected with COVID-19 or impacts the recovery from COVID-19, after release from hospital.
