Comparative analysis of the course of COVID-19 and post-COVID syndrome in patients with inflammatory bowel disease and COVID-19 caused by the Omicron strain and earlier strains

BACKGROUND: Patients with inflammatory bowel disease have specific features of the course of COVID-19 and post-COVID syndrome. The available literature is limited in data comparing the course of COVID-19 of different strains in patients with inflammatory bowel disease as well as assessing the course of post-COVID syndrome. AIM: To conduct a comparative analysis of the course of COVID-19 and post-covid syndrome in patients with inflammatory bowel disease and COVID-19 caused by the Omicron strain and earlier strains. MATERIALS AND METHODS: The study included 159 patients diagnosed with ulcerative colitis and Crohns disease and COVID-19, who were observed in two temporary infectious diseases hospitals in Kazan (Republican Clinical Hospital and City Clinical Hospital No. 7) and on outpatient basis since April 2020 to May 2022. For a comparative analysis of the course of COVID-19 and post-COVID syndrome in patients who had come through COVID-19, 2 periods were defined: the 1st period from March 2020 to December 2021, the 2nd period from January 2022. RESULTS: None of the patients with Omicron developed lung damage (0 (0%) vs 36 (44.4%), p 0.05). It has been also found that among patients with Omicron there were more patients with comorbidity (62 (79.5%) versus 50 (61.7%), (p 0.05). Dynamic observation of the patients has revealed that post-covid syndrome was significantly less common in the patients with Omicron for 3 months after COVID-19 (25.6% vs. 47.1%). When analyzing the complaints associated with asthenia, it was found that they were significantly more common in the patients with Omicron 3 months after COVID-19 (58 (74.3%) in comparison with 17 (50%), p 0.05). The complaints associated with cognitive impairment (0 (0%) vs. 3 (8.8%), p 0.05) and depression (Hospital Anxiety and Depression Scale (31 (39.7%) vs. 22 (64.7%), p 0.05), Hamilton scale (22 (28.2%) vs. 22 (64.7%), p 0.05)) were significantly less common in the patients with Omicron for 3 months after COVID-19. After analyzing the activity in the patients with inflammatory bowel disease before COVID-19 and 3, 6, 9 months after COVID-19, we have found that the maximum number of patients with the exacerbation of inflammatory bowel disease was noted after 3 months in the patients with Omicron and after 6 months in the patients with earlier strains. CONCLUSIONS: Thus, the results of the study have shown that in the patients with inflammatory bowel disease, both in ulcerative colitis and Crohns disease, the course of COVID-19 caused by the Omicron strain proceeded in a milder form compared with the patients who had earlier strains. In the patients with Omicron, complaints characteristic of post-COVID syndrome were less common. After a previous infection with COVID-19, the frequency of inflammatory bowel disease relapses increased: in the patients with Omicron due to mild exacerbation 3 months after COVID-19; in the patients with earlier strains due to moderate and severe relapse.