Background In Korea, it has been reported that the incidence of some respiratory diseases and Kawasaki diseases has decreased compared to the previous year along with active non-pharmaceutical interventions in the early stages of the COVID-19 pandemic. Autoimmune inflammatory rheumatic disease (AIIRD) is mainly affected musculoskeletal organs and connective tissues due to impaired immune regulation. Although gout and osteoarthritis are rheumatic diseases, they are not a disease of the immune system, and are not included in the AIIRD.

Objectives In this study, we investigated the change and difference in the incidence rate of various rheumatic diseases during the COVID-19 pandemic after 2020.

Methods The number of patients for each disease from January 2016 to December 2020 was obtained from the Korea Health Insurance Review and Assessment Service database. We compared the incidence of 9 rheumatic diseases [systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), ankylosing spondylitis (AS), Sjogren syndrome (SJS), Behcet’s disease (BD), inflammatory myositis (IIM), scleroderma, polymyalgia rheumatica (PMR), and gout] and hypertension before and after the COVID-19 outbreak. The incidence rates of patients before and after the COVID-19 outbreak were compared using the Poisson test.

Results From 2016 to 2019, the prevalence of rheumatic diseases showed gradually increased. In 2020, the incidence of SLE, AS, SJS, BD, and IIM were significantly decreased compared to the previous 4 years. In contrast, the incidences of gout and hypertension during the COVID-19 pandemic period were significantly increased from the predicted values.

Conclusion In conclusion, we found that the incidence of many AIIRDs, including SLE, AS, SJS, BD, and IIM decreased despite the increased incidence of hypertension and gout during the COVID-19 pandemic.

References [1]Huh K, Kim YE, Ji W et al. Decrease in hospital admissions for respiratory diseases during the COVID-19 pandemic: a nationwide claims study. Thorax 2021;76:939-41.

[2]Kang JM, Kim YE, Huh K et al. Reduction in Kawasaki Disease After Nonpharmaceutical Interventions in the COVID-19 Era: A Nationwide Observational Study in Korea. Circulation 2021;143:2508-10.

Disclosure of Interests None declared