The presence of fatigue symptoms up to 6-7 months after acute COVID-19 disease, similar to myalgic encephalomyelitis/chronic fatigue syndrome, also observed after other viral infections, have been reported as the most frequent post-COVID-19 symptom (Townsend et al., 2020).~There is a physiological plausibility for OSA being a causal factor to COVID-19 morbidity and fatigue symptoms by nocturnal hypoxemia, exacerbating or causing endothelial dysfunction, inflammation, oxidative stress, microaspiration and cardiac dysfunction. OSA activates the renin-angiotensin-aldosterone system (RAAS) and angiotensin-converting enzyme-2 (ACE2), which is the SARS-CoV-2 entry receptor in the cells (Miller et al., 2021).~In this study we will identify the prevalence of OSA and it's relation with post-COVID-19 fatigue that remains for at least six month after the acute disease, in patients that attend the post-COVID-19 Out Patients Hospital Clinics. It will be studied also the relation between fatigue and vaccination status, nocturnal hypoxemia, day time sleepness and the acute COVID-19 severity.~Data collection will be performed by a questionnaire administered by qualified clinical study staff (i.e., by physicians who conduct the post-COVID-19 medical consultation).~Demographic, clinical data and clinical research forms will be collected between 6-7th month after the diagnosis of COVID-19 (t1) and 9 months later (t2).~Fatigue will be assessed using the Chalder fatigue scale - CFQ-11 (Chalter et al., 1993).~The evaluation of OSA related daytime sleepiness will be measured using the Epworth Sleepiness Scale - ESS (Johns, 1991). The OSA diagnosis will be performed using portable monitoring device type III (in-home polygraphy), between 6-7th month after the diagnosis of COVID-19 (t1).
Identify the relationship of obstructive sleep apnea (OSA) prevalence with post-COVID-19 fatigue that remains at least six months after acute disease