Supplementary Material for: Impaired sleep in patients with post-COVID-19 syndrome compared to healthy controls: A cross-sectional trial.

Introduction: To objectify self-reported sleep disorders in individuals with Post-COVID-syndrome (PCS), we aimed to investigate the prevalence and nature of sleep disturbances by polysomnography (PSG) in PCS compared to healthy individuals. Methods: People with PCS (n=21) and healthy controls (CON, n=10) were included in this prospective trial. At baseline, clinical and social anamnesis, lung function, 1-minute sit-to-stand test (STST) and Pittsburgh Sleep Quality Index (PSQI) were assessed. For a single-night, sleep health was evaluated by video-PSG. The apnea/ hypopnea index (AHI) was used as the primary outcome. Results: Twenty patients with PCS (50±11y, BMI 27.1m2/kg, SARS-CoV-2 infection 8.5±4.5 months ago) and 10 CON participants (46±10y, BMI 23.0m2/kg, no SARS-CoV-2 infection in the history) completed the study. Forced vital capacity (p=0.018), STST repetitions (p<0.001) and symptoms of dyspnoea (at rest: p=0.002, exertion: p<0.001) were worse in PCS compared to CON. PSQI score (PCS: 7.5±4.7 points) was higher in PCS compared to CON (Δ=3.7points, 95%CI [0.4 to 7.1] p=0.015), indicating poor sleep in 80% of patients with PCS. Although PSG showed comparable sleep stage distributions in both groups, AHI index (Δ=9.0n/h, 95%CI [3.3 to 14.8], p=0.002), PLM index (Δ=5.1n/h, 95%CI [0.4 to 9.8], p=0.017) and the prevalence of sleep apnea (60% vs. 10%, p=0.028) was significantly higher in PCS compared to CON. Conclusion: Quantifiable subjective limitations of sleep have been revealed by PSG data in this PCS cohort. More than half of PCS patients had signs of sleep apnea, highlighting the importance of sleep screening in PCS.