Biologic Prescribing Decisions Following Serious Infection; Results from the British Society for Rheumatology Biologics Register – Rheumatoid Arthritis (BSRBR-RA)

Objectives: To establish whether the decision to stop, continue or switch tumour necrosis factor inhibitor therapy (TNFi) to a biologic drug with an alternative mode of action following a serious infection (SI) impacts upon the risk of recurrent SI in patients with RA.
Methods: Patients recruited to the BSRBR-RA with at least one episode of SI whilst on TNFi were included. The biologic treatment decision following SI was considered. A multivariable adjusted Cox proportional hazards model was used to identify predictors of recurrent SI and whether biologic treatment choices influenced future SI risk.
Results: In total,1583 patients suffered at least 1 SI whilst on TNFi. Most patients (73%) were recorded as continuing TNFi 60 days after an index SI. The rate of recurrent SI was 25.6% per annum (95%CI 22.5-29.2). The rate of recurrent SI was highest in patients who stopped their TNFi; 42.6% per annum (95%CI 32.5-55.7) and lowest in those who switched biologic drug class (12.1% per annum, 95%CI 3.9-37.4). Compared to patients stopping biologic therapy, patients who continued or switched drug class had significantly lower risk of recurrent SI (drug continuation HR 0.54, 95%CI 0.40-0.74, drug switch HR 0.29, 95%CI 0.09-0.95).
Conclusion: Patients who continued or switched their TNFi post index SI had a lower risk of recurrent SI infection compared to those who stopped the drug. This may be explained by better control of disease activity with reintroduction of biologic therapy, a driving factor for SI or alternatively channelling fitter patients to restart biologic therapy.