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

Abstract 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.