COVID-19 Outcomes in Patients With Systemic Autoimmune Rheumatic Diseases Compared to the General Population: A US Multicenter, Comparative Cohort Study

Objective: Patients with systemic autoimmune rheumatic diseases (ARDs) continue to be concerned about risks of severe coronavirus disease 2019 (COVID-19) outcomes. This study was undertaken to evaluate the risks of severe outcomes in COVID-19 patients with systemic ARDs compared to COVID-19 patients without systemic ARDs.

Methods: Using a large multicenter electronic health record network, we conducted a comparative cohort study of patients with systemic ARDs diagnosed as having COVID-19 (identified by diagnostic code or positive molecular test result) compared to patients with COVID-19 who did not have systemic ARDs, matched for age, sex, race/ethnicity, and body mass index (primary matched model) and additionally matched for comorbidities and health care utilization (extended matched model). Thirty-day outcomes were assessed, including hospitalization, intensive care unit (ICU) admission, mechanical ventilation, acute renal failure requiring renal replacement therapy, ischemic stroke, venous thromboembolism, and death.

Results: We initially identified 2,379 COVID-19 patients with systemic ARDs (mean age 58 years; 79% female) and 142,750 comparators (mean age 47 years; 54% female). In the primary matched model (2,379 patients with systemic ARDs and 2,379 matched comparators with COVID-19 without systemic ARDs), patients with systemic ARDs had a significantly higher risk of hospitalization (relative risk [RR] 1.14 [95% confidence interval (95% CI) 1.03-1.26]), ICU admission (RR 1.32 [95% CI 1.03-1.68]), acute renal failure (RR 1.81 [95% CI 1.07-3.07]), and venous thromboembolism (RR 1.74 [95% CI 1.23-2.45]) versus comparators but did not have a significantly higher risk of mechanical ventilation or death. In the extended model, all risks were largely attenuated, except for the risk of venous thromboembolism (RR 1.60 [95% CI 1.14-2.25]).

Conclusion: Our findings indicate that COVID-19 patients with systemic ARDs may be at a higher risk of hospitalization, ICU admission, acute renal failure, and venous thromboembolism when compared to COVID-19 patients without systemic ARDs. These risks may be largely mediated by comorbidities, except for the risk of venous thromboembolism.