Biologic prescribing decisions following serious infection: results from the British Society for Rheumatology Biologics Register-Rheumatoid Arthritis.

Abstract

To establish whether the decision to stop, continue or switch TNF inhibitor (TNFi) therapy 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. Patients recruited to the British Society for Rheumatology Biologics Register-RA with at least one episode of SI while 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. In total, 1583 patients suffered at least one SI while 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 with patients stopping biologic therapy, patients who continued or switched drug class had significantly lower risk of recurrent SI (drug continuation hazard ratio = 0.54, 95% CI: 0.40, 0.74; drug switch hazard ratio = 0.29, 95% CI: 0.09, 0.95). Patients who continued or switched their TNFi post-index SI had a lower risk of recurrent SI infection compared with 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.