COVID-19 Outcomes Assessed Among Patients With Autoimmune Inflammatory Rheumatic Diseases in South Korea

doctor and female patient, masks, COVID19
Doctor checking and inquired Asian elderly woman patient wearing a face mask in hospital for protect infection and kill Novel Corona virus Covid-19 virus.
Researchers conducted a nationwide cohort study to determine the association between autoimmune inflammatory rheumatic diseases and COVID-19 in South Korea, early in the pandemic.

Early in the COVID-19 pandemic, autoimmune inflammatory rheumatic diseases were found to be associated with an increased likelihood of testing positive for SARS-CoV-2, as well as worse clinical outcomes and death from COVID-19, according to study results published in Lancet Rheumatology.

Researchers performed an exposure-driven, propensity score-matched study in South Korea. Patients aged 20 years and older who received reverse transcription polymerase chain reaction (RT-PCR) testing for SARS-CoV-2 between January 1 and May 30, 2020 and who received general health examination results from the Korean National Health Insurance Service were included in the analysis. Autoimmune inflammatory rheumatic diseases were defined using relevant International Statistical Classification of Diseases, Tenth Revision (ICD-10) codes, with at least 2 claims within a year.

Study outcomes were SARS-CoV-2 positivity, severe COVID-19, including requirement of oxygen therapy, intensive care unit (ICU) admission, invasive ventilation, and death, and COVID-19-related mortality.

Overall, 133,609 patients (52.5% women) completed the general health exam and were tested for SARS-CoV-2. Of these patients, 4365 (3.3%) tested positive for SARS-CoV-2 and 8297 (6.2%) were diagnosed with autoimmune inflammatory rheumatic diseases.

After matching, patients with autoimmune inflammatory rheumatic diseases were more likely to test positive for SARS-CoV-2 (fully adjusted odds ratio [OR], 1.19; 95% CI, 1.03-1.40; P =.026), have severe COVID-19 outcomes (fully adjusted OR, 1.26; 95% CI, 1.02-1.59; P =.041), and COVID-19-related death (fully adjusted OR, 1.69; 95% CI, 1.01-2.84; P =.046). Results were similar in patients with connective tissue disease and inflammatory arthritis.

The odds of testing positive for SARS-CoV-2, developing severe COVID-19, and COVID-19-related death were not associated with treatment with any dose of systemic corticosteroids or disease-modifying antirheumatic drugs (DMARDs), except in the case of patients receiving 10 mg or more of systemic corticosteroids. Patients receiving 10 mg or more of corticosteroids had an increased likelihood of a positive SARS-CoV-2 test (fully adjusted OR, 1.47, 95% CI, 1.05-2.03; P =.022), severe COVID-19 outcomes (fully adjusted OR, 1.76; 95% CI, 1.06-2.96; P =.031), and COVID-19-related death (fully adjusted OR, 3.34; 95% CI, 1.23-8.90; P =.017).

Study limitations included ICD-10 codes being an imprecise method of diagnosis; the cohort having characteristics that may be unrepresentative of the general population; accurate data on viral loads and contact tracing being unavailable; and the improvement of the overall COVID-19 outcomes owing to physician experience and management strategies.

Researchers concluded, “[O]ur study advances the understanding of the relationship between autoimmune inflammatory rheumatic disease, including its treatment, and the pathogenesis of COVID-19.” However, they noted, “Because we used the dataset that reflected the initial period of the pandemic in South Korea, caution should be exercised when [generalizing] our results to the current situation.”


Shin YH, Shin JI, Moon SY, et al. Autoimmune inflammatory rheumatic diseases and COVID-19 outcomes in South Korea: a nationwide cohort study. Lancet Rheumatol. Published online June 18, 2021. doi:10.1016/S2665-9913(21)00151-X