Influence of clinical features in acute COVID-19 infection on the course of post-COVID syndrome

The COVID-19 pandemic caused by the SARS-CoV-2 virus has resulted in global morbidity and high mortality rates worldwide. According to case histories, for a long time after acute COVID-19 infection (six months to 2-3 years), patients may experience a pronounced fatigue, increased tiredness, higher incidence of acute respiratory viral infections per year, increased recurrence of skin diseases, allergies, exacerbation of pulmonary disorders, urinary tract diseases, increased recurrence of chronic viral diseases, e.g., herpesvirus and papillomavirus infections, aggravation of chronic cardiovascular and other somatic diseases of various organs and systems. Patients were examined at early as six months after recovery from acute COVID-19. Such persistent post-infectious consequences are referred to as post-COVID syndrome. When assessing post-COVID syndrome, it is necessary to identify the main clinical syndromes of multiorgan pathology characteristic of post-COVID patients. Endocrine and cardiac manifestations of post-COVID syndrome may be a consequence of direct damage from viral infection, immunological and inflammatory damage, as well as iatrogenic complications. Objective of our study was to assess the impact of acute COVID-19 severity on the course of post-COVID syndrome. The research objectives were as follows: 1. To analyze the severity of clinical manifestations of cardiovascular disorders in post-COVID patients depending on the degree of lung damage in the acute period of COVID-19 (CT0 to CT4). 2. To analyze the severity of clinical manifestations of endocrine disorders, including newly diagnosed pathology, in post-COVID patients depending on the degree of lung damage in acute period of COVID-19. Since we did not found any significant gender-and age-dependent differences, all patients were divided into groups by the degree of lung damage during acute period of COVID-19, according to clinical guidelines for the diagnosis and treatment of a new coronavirus infection. This study showed that the clinical picture of post-COVID syndrome is characterized by a pronounced diversity in development of multiple organ pathology, both newly diagnosed, or manifesting by increased frequency of exacerbations of chronic diseases. Conclusions: 1. According to the data obtained, reliable differences were obtained between groups CT0 and CT1-2, as well as CT0 and CT3-4: the frequency of exacerbating cardiovascular disorders in the post-COVID period is significantly higher in groups with lung damage over acute period of COVID-19 compared to the group of patients without lung damage. These data suggest that cardiovascular disorders are directly related to the severity of COVID-19, viral load, and were detected most frequently (68%) in post-COVID patients who initially had a severe coronavirus infection. 2. According to our results, the frequency of glucose metabolism disorders, including those detected for the first time, proved to be significantly increased in the post-COVID patients with lung damage during acute infection. Meanwhile, no significant differences were found for thyroid disorders, except of autoimmune thyroiditis (AIT). These disorders may be associated with usage of corticosteroid therapy in acute period of coronavirus infection, or with impairment of regulatory mechanisms of the endocrine and immune systems induced by SARS-CoV-2 virus, thus again confirming our assumptions concerning development of multiple organ pathology in post-COVID patients.