Pos0275 covid-19 Infection in Patients With Rheumatic Disease During Omicron Outbreak in South Korea: A Single-Center Prospective Study

Abstract

BackgroundHigh transmissibility and immune evasion of SARS-CoV-2 Omicron variant made it dominant variant worldwide since January 2022. Before Omicron era, several studies demonstrated that autoimmune inflammatory rheumatic disease (AIIRD) patients were vulnerable to COVID-19 infection compared to general population. However, there is a lack of epidemiologic data regarding COVID-19 outbreak in patients with AIIRD in Omicron era.ObjectivesTo identify incidence rate, hospitalization rate and potential risk factors for COVID-19 outcomes in AIIRD patients during Omicron outbreak.MethodsThis study was a prospective longitudinal study from January 1 to October 31, 2022. We included patients who visited rheumatology outpatient clinic in a nationwide, tertiary referral center in South Korea. Included patients were classified into two groups (AIIRD and non-AIIRD groups) based on underlying disease. Vaccination and infection history of COVID-19 were obtained through self-report via questionnaire and data from Korea Disease Control and Prevention Agency (KDCA). Main outcome of this study was an incidence of COVID-19 infection during the observation period. Clinical factors associated with the incidence of COVID-19 infection were investigated using Cox proportional hazard model. In the final multivariable model, clinical factors that showed a relevant association (P < 0.1) with the outcome in the univariable analysis were included as covariates.ResultsA total of 1,814 patients were analyzed (AIIRD group: 1,535, non-AIIRD group: 279). The COVID-19 incidence in AIIRD group (47.6%) was higher than that reported in general population of South Korea (43.9%) and this trend was prominent in those aged < 70 years. Longitudinal change in COVID-19 incidence during the observation period showed two peaks in March and August in both groups, which was the same trend with general population. There were 30 cases of hospitalization due to COVID-19 infection, with the rate was comparable between AIIRD and non-AIIRD groups (1.7% vs. 1.5%, P = 0.970). The incidence rate of COVID-19 in the AIIRD group was comparable to that in the non-AIIRD group (47.6% vs. 44.8%, P = 0.386). In the AIIRD group, COVID-19 infection occurred less frequently in patients with old age (≥70 years) and those receiving glucocorticoid treatment. Other clinical factors such as use of DMARDs and biologics, and underlying diseases were not associated with COVID-19 incidence in the multivariable analysis. Of note, at least one COVID-19 vaccination did not lower its incidence (unadjusted HR 1.06 [95% CI 0.82-1.38]). Although patients who received booster vaccination were less likely to be infected with COVID-19 (unadjusted HR 0.79 [0.68-0.92]), this protective effect was significant only in patient younger than 70 years (Figure 1).ConclusionDuring the Omicron outbreak in South Korea, incidence of COVID-19 infection in patients with AIIRD and non-AIIRD was comparable. Immunomodulatory agents and specific rheumatic diseases did not increase the COVID-19 incidence, and booster vaccination against COVID-19 decreased the infection only in patients younger than 70 years.REFERENCES:NIL.Acknowledgements:NIL.Disclosure of InterestsNone Declared.