INCIDENCE and RISK FACTORS of COVID-19 in PATIENTS with VASCULITIS: A DANISH NATIONWIDE COHORT STUDY

ABSTRACT

Background: Patients with small vessel vasculitis (SVV) and large vessel vas-culitis (LVV, including giant cell arteritis (GCA)) are considered at higher risk of infections compared to the general population, owing to their underlying condition and the use of immunosuppressive drugs. Thus, the risk of COVID-19 infection and related outcomes during the global pandemic is of immediate concern to rheumatologists worldwide. Objectives: To estimate the incidence of COVID-19 hospitalisation in patients with vasculitis, and to evaluate the impact of glucocorticoid treatment on the outcome between March 2020 and February 2021. Methods: With use of the Danish nationwide registers, a cohort of patients with LVV and SVV, respectively, and general population controls (GPCs) matched on age and gender was established. Hazard ratios (HR) for COVID-19 hospitalisation was estimated. National COVID-19 surveillance data was used to calculate the odds ratio (OR) of having had a positive SARS-CoV2 PCR test. Lastly, a nested case-control design and conditional logistic regression was used to estimate the impact of glucocorticoids on the risk of hospitalisation. Results: Patients with SVV (n=1090) had an increased incidence of COVID-19 hospitalisation compared with GPCs (comorbidity-adjusted HR 2·73;95% CI 1·64-4·55), whereas no increased risk was seen in patients with LVV. Patients with vasculitis had similar likelihoods of having had a positive PCR test as GPCs. Glucocorticoids did not increase the HR of hospitalisation among patients with LVV or SVV. Conclusion: Patients with SVV were more likely to be admitted with COVID-19 than the GPCs. The impact of glucocorticoid treatment on the risk of hospitalisation needs further investigation.