Outcomes following SARS-CoV-2 infection in individuals with and without inflammatory rheumatic diseases: a Danish nationwide cohort study

OBJECTIVE: In a setting with an extensive SARS-CoV-2 test strategy and availability of effective vaccines, we aimed to investigate if patients with inflammatory rheumatic diseases (IRD) face greater risk of contracting SARS-CoV-2 and have a worse prognosis of increased risk of hospitalisation, assisted ventilation and death compared with the general population.

METHODS: This was a nationwide, population-based register study that compared outcomes of SARS-CoV-2 infection in Danish patients with IRD (n=66 840) with matched population controls (n=668 400). The study period was from March 2020 to January 2023. Cox regression analyses were used to calculate incidence rate ratios (IRRs) for SARS-CoV-2-related outcomes.

RESULTS: We observed a difference in time to first and second positive SARS-CoV-2 test in patients with IRD compared with the general population (IRR 1.06, 95% CI 1.05 to 1.07) and (IRR 1.21, 95% CI 1.15 to 1.27). The risks of hospital contact with COVID-19 and severe COVID-19 were increased in patients with IRD compared with population controls (IRR 2.11, 95% CI 1.99 to 2.23) and (IRR 2.18, 95% CI 1.94 to 2.45). The risks of assisted ventilation (IRR 2.33, 95% CI 1.89 to 2.87) and COVID-19 leading to death were increased (IRR 1.98, 95% CI 1.69 to 2.33). Patients with IRD had more comorbidities compared with the general population. A third SARS-CoV-2 vaccination was associated with a reduced need for hospitalisation with COVID-19 and reduced the risk of death.

CONCLUSION: Patients with IRD have a risk of SARS-CoV-2, which nearly corresponds to the general population but had a substantial increased risk of hospitalisation with COVID-19, severe COVID-19, requiring assisted ventilation and COVID-19 leading to death, especially in patients with comorbidities.