Moderate to Severe Obstructive Sleep Apnea Is a Risk Factor for Severe <scp>COVID</scp> ‐19—A Nationwide Cohort Study

The impact of obstructive sleep apnea (OSA) and positive airway pressure (PAP) treatment on COVID-19 severity is unclear. In this population-based, nationwide study using multi-register data, we aimed to assess if OSA is a risk factor for COVID-19 severity and how adherence to PAP treatment and clinical characteristics affect the risk. Swedish residents with COVID-19 infection January 2020-May 2022 were included. An exposed group of OSA (starting PAP treatment 2015-2019) was identified. COVID-19 severity outcome was defined as mild (non-hospitalised), severe (hospitalised) or critical (intensive care or death). Covariates included comorbidities and sociodemographics. Conditional odds ratios (COR) with 95% confidence intervals (95% CI) were estimated using multinomial logistic regression. Among 8,894,162 individuals in Sweden, 1,932,081 (21.7%) had registered COVID-19 January 2020-May 2022. OSA was identified in 11,407 (0.6%) and was associated with an increased risk of severe (COR 1.34; 95% CI 1.25-1.43) and critical (1.25; 1.11-1.42) COVID-19 after adjustment for age, sex, education and comorbidities. Stratified by PAP adherence, age and COVID-19 wave, OSA was a risk factor for more severe COVID-19 in PAP-adherent and non-adherent individuals, in people aged 40-60 but not > 60 years and not after June 2021. OSA severity, assessed with the oxygen desaturation index (ODI), was independently associated with COVID-19 severity, with the highest risks for severe (1.23; 1.01-1.52) and critical (1.76; 1.17-2.63) COVID-19 observed in ODI ≥ 30 (vs. ODI < 15). We conclude that patients with moderate to severe OSA have an increased risk of severe COVID-19, also when PAP-treated, with an independent dose-response relationship between the severity of intermittent hypoxia and COVID-19 severity.