Comparative Burden of COVID-19 in Adults with Rheumatic Diseases and Immunocompetent Individuals: A Population-Based Cohort Study in Quebec, Canada, 2020-2023

The study compared the burden of COVID-19 in 81,434 adults with systemic autoimmune rheumatic diseases (SARDs) with 2,020,356 individuals with other chronic comorbidities and 3,144,700 individuals without comorbidities during the pandemic from March 2020 to April 2023. Despite similar infection rates, patients with SARDs had significantly higher risk of hospitalization and intensive care unit admission or death throughout all pandemic periods. During the pre-vaccination period, the risk of hospitalization was 3.4 times higher and the risk of ICU admission or death was 4 times higher. These elevated risks persisted during the Omicron variant period (4.5 times and 4.4 times higher, respectively). Among SARD diseases, rheumatoid arthritis, psoriatic arthritis, and systemic lupus erythematosus caused the highest burden. Patients treated with highly immunosuppressive medications rituximab or mycophenolate had the highest risk of hospitalization and death, particularly during the Omicron period.