Risk of severe COVID-19 in patients with inflammatory rheumatic diseases treated with immunosuppressive therapy in Scotland

Objectives

To investigate the association of severe COVID-19 in those with inflammatory rheumatic diseases (IRD) treated with immunosuppressive drugs.

Methods

A list of 4633 patients on biologics and targeted synthetic (ts) DMARDs in March 2020 was linked to a case-control study that includes all cases of COVID-19 in Scotland.

Results

By 22 November 2021 433 of the 4633 patients treated with biologics and tsDMARDs had been diagnosed with COVID-19, of whom 58 had been hospitalised. With all those in the population not on DMARDs as reference category, the rate ratio for hospitalised COVID-19 associated with DMARD treatment was 2.14 (95% CI 2.02 to 2.26) in those on conventional synthetic (cs) DMARDs, 2.01 (95% CI 1.38 to 2.91) in those on TNF inhibitors as the only biologic agent, and 3.83 (95% CI 2.65 to 5.56) in those on other biologic agents. Among those on csDMARDs, rate ratios for hospitalised COVID-19 were lowest at 1.66 (95% CI 1.51 to 1.82) in those on methotrexate and highest at 5.4 (95% CI 4.4 to 6.7) in those on glucocorticoids at average dose >10 mg/day prednisolone equivalent.

Conclusion

The risk of hospitalised COVID-19 is elevated in IRD patients treated with immunosuppressive drugs. Of these drugs, methotrexate, hydroxychloroquine, and TNF inhibitors carry the lowest risk, JAK inhibitors and B-cell depleting agents a higher risk and prednisolone the highest risk. A larger study is needed to estimate reliably the risks associated with each class of biologic agent.

Key messages

• Risk of hospitalised COVID-19 is about twofold higher in IRD patients treated with immunosuppressive therapies – csDMARDS or biologics – than in the general population.

• Risk is lowest in those treated with methotrexate, hydroxychoroquine and TNF inhibitors. Of the other biologic drugs, treatment with B cell depleters and JAK inhibitors is associated with higher risk but the numbers are too small for risk associated with each drug class to be estimated reliably.

• The risk of severe COVID-19 with glucocorticoids at a dose greater than 10 mg/day prednisolone equivalent is higher than that of any other drug class studied.