Patterns of sleep disorders after a new coronavirus infection COVID-19

Background. Sleep disorders have a negative impact on many aspects of life. COVID-19 exacerbates this problem in the context of the post-COVID syndrome where sleep disorder is one of the common complaints.Objective. We aimed to assess the frequency of sleep disorders after COVID-19 and the presence of associations between post-COVID sleep disorders and the severity of COVID-19.Material and methods. A cross-sectional study was carried out in Novosibirsk. It included 115 people aged 26 to 74 years (an average age of 54.22 ± 12.48 years) after recovery from COVID-19, which occurred two to eleven months before. Patients underwent questionnaire survey (Spiegel sleep score questionnaire, HADS Anxiety and Depression Scale, International Restless Legs Syndrome (RLS) Severity Scale), examination by a somnologist, and screening night computer pulse oximetry. If an index of desaturations was more than five per hour, we performed overnight somnography by WAtch PAT 200 or polysomnography. Patients were divided into groups depending on the presence of sleep disorders, COVID-19 severity, and their age. Statistical analysis included a descriptive analysis. Odds ratio was assessed by determining the risk measure for dichotomous variables in the contingency table.Results. RLS was the most common post-COVID sleep disorder (n = 63, 75%). However, primary insomnia was diagnosed only in patients with moderate-to-severe course of COVID-19 (n = 3, 9%). There were 40 patients with post-COVID sleep disorder; they had significantly lower sleep time on workdays (7.00 [6.00; 7.50] vs. 7.50 [6.50; 8.00] hours, p = 0.021) and significantly higher mean HADS depression score (5.00 [3.00; 7.00] vs. 3.00 [1.00; 6.00] points, p = 0.006) compared with the corresponding parameters in patients without deterioration of sleep quality. The chance of reduced sleep quality was 11.6 times higher after moderate-to-severe COVID-19 infection than that after mild infection only in patients aged 26-59 years (95% confidence interval 1.42-94.32, p = 0.007).Conclusion. The chance of worsening sleep quality was significantly higher after a moderate-to-severe COVID-19 infection than after mild infection in 26-59-year-old old patients. At the same time, RLS was the most common post-COVID sleep disorder according to our study. Given the importance of sleep disorders, working-age patients after moderate-to-severe COVID-19 infection require active monitoring by doctors in order to timely correct emerging complaints.