A new meta-analysis of 48 observational studies that included 8,664,026 people reveals that pre-existing sleep disturbances are tied to an increased risk of COVID-19 infection and worse outcomes if infected. The study is published in eClinicalMedicine.
Previous studies have shown that up to 50% of COVID-19 patients experience sleep disturbances, and sleep disturbances are linked to "daytime drowsiness, work burnout, and low spirits but also induce immune deficiency and systematic inflammation," the authors note.
For the purposes of this study, sleep disturbances included obstructive sleep apnea (OSA), insomnia, abnormal sleep duration (less than 6 hours or more than 9), night-shift work, and restless legs syndrome already documented before infection with COVID-19
The studies analyzed had sample sizes ranging from 118 to 4.9 million and were conducted in 15 countries, including 19 studies based on US patients.
Pre-existing sleep disturbances were tied to an increased risk of COVID-19 infection of 12% (odds ratio [OR], 1.12; 95% confidence interval [CI], 1.07 to 1.18), hospitalization of 25% (OR, 1.25; 95% CI, 1.15 to 1.36), death of 45% (OR, 1.45; 95% CI, 1.19 to 1.78), and long COVID of 36% (OR, 1.36; 95% CI, 1.17 to 1.57).
Findings differ by age, sex
Age and gender played a role in the findings, with men with sleep disturbances more likely to die from COVID than women with sleep disturbances.
Young individuals with pre-existing sleep disturbances had a higher susceptibility and hospitalization for COVID-19 than those without.
"Young individuals with pre-existing sleep disturbances had a higher susceptibility and hospitalization for COVID-19 than those without. This finding further confirmed the compromised immune function induced by sleep disturbances," the authors wrote. "In old individuals, those with pre-existing sleep disturbances elevated the hospitalization and mortality of COVID-19 but did not increase the susceptibility compared with those without."