Identification of Risk Factors for COVID-19 Hospitalization in Patients With Anti-Rheumatic Drugs: Results From a Multicenter Nested Case Control Study.

Patients with inflammatory rheumatic diseases (IRDs) do not have an increased risk for coronavirus disease 2019 (COVID-19) compared with the general population. However, it remains uncertain whether subgroups of patients with IRD using different immunosuppressive antirheumatic drugs carry a higher risk for severe COVID-19 compared with other patients with IRD. The aim of this study is to identify risk factors for severe COVID-19, requiring hospitalization in patients with IRD. This is a multicenter nested case control study conducted in the Netherlands. Cases are hospital known patients with IRD requiring hospitalization for COVID-19 between March 1, 2020, and May 31, 2020. Controls are hospital known patients with IRD not requiring hospitalization for COVID-19 in this period, included at a 4:1 ratio. Patient, disease, and treatment characteristics were extracted from electronic medical records and a questionnaire. Potential risk factors were analyzed using unconditional logistic regression, corrected for confounders and multiple testing. Eighty-one cases and 396 controls were included. General risk factors of older age and obesity apply to patients with IRD as well (odds ratio (OR) for age ≥ 75 3.5, 95% confidence interval (CI) 1.9-6.3, OR for body mass index ≥ 40 4.5, 95% CI 1.5-14). No significantly increased ORs for COVID-19 hospitalization were found for any antirheumatic agent or IRD. A protective effect was found for use of methotrexate (OR 0.53, 95% CI 0.31-0.92). In conclusion, similar to the general population, elderly and obese patients with IRD have a higher risk for hospitalization for COVID-19. We did not identify a specific antirheumatic agent or IRD to increase the risk of COVID-19 hospitalization in patients with IRD, except for a possible protective effect of methotrexate.