Level of disease activity and the use of certain medications are associated with the risk of death from COVID-19 among patients with rheumatic diseases, according to an analysis from the Global Rheumatology Alliance physician-reported registry. 

“There is a lack of robust data to inform our understanding of outcomes following SARS-CoV-2 infection in patients with inflammatory rheumatic diseases, leading to uncertainties regarding chronic disease management, especially for those taking immunosuppressant or immunomodulatory drugs,” wrote an international group of study authors led by Dr Anja Stranfeld, of the German Rheumatism Center in Berlin, and including others in the UK. 

The study, published in Annals of the Rheumatic Diseases, analysed outcomes of 3,729 patients with rheumatic disease and confirmed or presumptive COVID-19.

The most common rheumatic disease was rheumatoid arthritis (37.4%), followed by connective tissue diseases other than systemic lupus erythematosus (SLE; 14.3%), SLE (10.5%), psoriatic arthritis (11.8%), and other spondyloarthritis (11.6%). A total of 390 of the patients (10.5%) died.

Some factors associated with the risk of death were similar to those seen in the general population with COVID-19. This included age: those aged 66 to 75 years had an odds ratio for COVID-19-related death of 3.00 (95% CI, 2.13-4.22) compared with those 65 years or younger. Those aged over 75 years had an OR compared to those 65 and under of 6.18 (95% CI, 4.47-8.53).

Male sex was also associated with increased risk of death, with an OR of 1.46 (95% CI, 1.11-1.91), as were hypertension combined with cardiovascular disease and chronic lung disease.

Importantly, the level of disease activity was also associated with the risk of COVID-19-related death. Patients with moderate/high disease activity had higher odds of dying compared with those in remission or with low disease activity, with an OR of 1.87 (95% CI, 1.27-2.77).

The use of rituximab was also significantly associated with the risk of death, with an OR of 4.04 (95% CI, 2.32-7.03), as was the use of sulfasalazine, and immunosuppressants including azathioprine, cyclophosphamide, ciclosporin, mycophenolate, or tacrolimus. Patients who were not receiving any disease-modifying anti-rheumatic drug had higher odds of death than those receiving methotrexate monotherapy, with an OR of 2.11 (95% CI, 2.48-3.01).

The authors noted that rituximab binds to CD20 on the surface of B-cells, effectively depleting them and interfering with antibody development. This suggests that rituximab may compromise antiviral immunity.

“People with rheumatic diseases with higher disease activity have higher odds of COVID-19-related death, highlighting the importance of disease control, preferably by managing DMARDs effectively without increasing glucocorticoids,” they concluded. “Future studies should address the observed association of rituximab and sulfasalazine with poor outcomes.”