Incidence and severeness of COVID-19 hospitalization in patients with inflammatory rheumatic disease: a nationwide cohort study from Denmark

Objectives. To estimate the incidence of COVID-19 hospitalization in patients with inflammatory rheumatic disease (IRD); in patients with RA treated with specific DMARDs; and the incidence of severe COVID-19 infection among hospitalized patients with RA. Methods. A nationwide cohort study from Denmark between 1 March and 12 August 2020. The adjusted incidence of COVID-19 hospitalization was estimated for patients with RA; spondyloarthritis including psoriatic arthritis; connective tissue disease; vasculitides; and non-IRD individuals. Further, the incidence of COVID-19 hospitalization was estimated for patients with RA treated and non-treated with TNF-inhibitors, HCQ or glucocorticoids, respectively. Lastly, the incidence of severe COVID-19 infection (intensive care, acute respiratory distress syndrome or death) among hospital-admitted patients was estimated for RA and non-IRD sp - individudals. Results. Patients with IRD (n=58 052) had an increased partially adjusted incidence of hospitalization with COVID-19 compared with the 4.5 million people in the general population [hazard ratio (HR) 1.46, 95% CI: 1.15, 1.86] with strongest associations for patients with RA (n=29 440, HR 1.72, 95% CI: 1.29, 2.30) and vasculitides (n=4072, HR 1.82, 95% CI: 0.91, 3.64). There was no increased incidence of COVID-19 hospitalization associated with TNF-inhibitor, HCQ nor glucocorticoid use. COVID-19 admitted patients with RA had a HR of 1.43 (95% CI: 0.80, 2.53) for a severe outcome. Conclusion. Patients with IRD were more likely to be admitted with COVID-19 than the general population, and COVID-19 admitted patients with RA could be at higher risk of a severe outcome. Treatment with specific DMARDs did not affect the risk of hospitalization.