Background Almost two years after the start of the pandemic, it has become clear that the severity of COVID-19 is not limited to the manifestations of the acute phase of SARS-CoV-2 infection. The so-called post-covid syndrome (PCS) can occur even in patients who have experienced mild or moderate COVID-19 and includes long-term symptoms that may be associated with residual inflammation, organ damage, non-specific effects of hospitalization or prolonged ventilation, social isolation, or comorbid diseases. In October 2021, the WHO defined PCS as a condition that occurs in individuals with a history of probable or confirmed infection with the SARS-CoV-2 virus, usually within 3 months of the onset of COVID-19, and is characterized by the presence of symptoms for at least 2 months, as well as the impossibility of explaining them with an alternative diagnosis.

Objectives To conduct a comparative assessment of clinical and demographic indicators in groups of patients with rheumatoid arthritis who underwent COVID-19, with and without PCS.

Methods The material of the questionnaires filled in by patients of the V.A. Nasonova Research Institute of Rheumatology, who underwent COVID-19, verified by RT-PCR for SARS-CoV-2 RNA. The information was supplemented with data from discharge records after inpatient treatment for COVID-19. Statistica program (version 12) was used for statistical processing. The results of correlation analysis were considered significant at p<0.05.

Results The study included 23 adult patients (over 18 years of age) with a reliable diagnosis of rheumatoid arthritis (ACR/EULAR). Of these, 11 (47.8%) patients noted the development of PCS (Group 1), and 12 patients underwent COVID-19 without consequences (Group 2). Both groups were represented predominantly by women (90.9% and 91.7%, respectively). The average age in both groups did not differ significantly and amounted to 56.73±14.79 years in group 1, and 48.17±19.59 years in group 2. The median number of comorbid diseases was 2 [1;4] in group 1 and 0.5 [0;2.5] in group 2. PCS was presented by the following symptoms: weakness, increased fatigue - in 6 patients, problems with attention, concentration - in 7, memory impairment - in 6, sleep disturbances - in 7, increased pain in the joints - in 7, shortness of breath during exercise - in 6, fluctuations in blood pressure - in 5, tachycardia - in 4. On average (median), each patient noted 10 [6.5;12] symptoms of PCS at a time. When assessing the number of symptoms in the infectious phase, in group 1, patients reported 20 [16;23], and in group 2, 10 [7;12] symptoms of COVID-19. At the time of development of COVID-19, the severity of RA symptoms, assessed by VAS, was 5.64±3.26 in group 1 and 4.75±2.99 in group 2. In group 1, 5 (45.5%) patients needed hospitalization, 3 of them needed oxygen support. In group 2, 4 (33.3%) patients were hospitalized, two of them needed oxygen support. 3 patients in group 1 suffered COVID-19 again on average 9.33±2.52 months after the first illness. One of them has been vaccinated. All patients in this group were treated as outpatients, while the first case of COVID-19 required one hospitalization and oxygen support.

Statistical assessment of significant differences (p<0.05) between groups in terms of sex, age, number of comorbid diseases, number of COVID-19 symptoms in the infectious phase, severity of RA symptoms, and hospitalization rate was not revealed.

Conclusion Even though when assessing the socio-demographic characteristics, no statistically significant differences were found between the study groups, the average age, the number of comorbid diseases, and the severity of RA symptoms at the time of COVID-19 were higher in the group of patients with RA and PCS. Patients with PCS reported higher rates of hospitalizations and more severe COVID-19. There were also repeated cases of COVID-19 in this group. It is necessary to continue the study on a larger cohort.

Disclosure of Interests None declared