Association between anti-tumour necrosis factor therapy and risk of ischaemic stroke in patients with rheumatoid arthritis: results from the British Society for Rheumatology Biologics Registers-Rheumatoid Arthritis (BSRBR-RA)

Abstract

BackgroundPeople with rheumatoid arthritis are at increased risk of cardiovascular morbidity and mortality, including stroke (cerebrovascular accident [CVA]). Anti-tumour necrosis factor (anti-TNF) therapy may influence the risk of CVA by reducing inflammation. The aim of the analysis was to study the association of anti-TNF therapy with risk of ischaemic CVA in rheumatoid arthritis. MethodsThe British Society for Rheumatology Biologics Registers-Rheumatoid Arthritis (BSRBR-RA) is an ongoing national prospective observational cohort study. Patients with rheumatoid arthritis recently started on anti-TNF therapy and a biologic-naive comparator group treated only with non-biologic disease modifying anti-rheumatic drugs (nbDMARDs) were recruited to the BSRBR-RA from 2001 to 2008. Patients were followed by physician and patient questionnaires and also linked to the national death register. Incident CVAs were identified from all three sources of follow-up. CVAs were validated against WHO criteria for CVA and further classified as ischaemic CVA using CT brain reports or if ischaemic CVA was reported as the underlying cause of death from death certificates according to International Classification of Diseases 10 (ICD-10) code I63. Patients with a previous CVA were excluded. Risk of ischaemic CVA was compared between the nbDMARD cohort and people ever exposed to anti-TNF using a Cox regression model. Missing baseline data were replaced by multiple imputation. Adjustment was made for confounders using propensity scores stratified by deciles. FindingsTo Oct 31, 2010, 130 verified incident ischaemic CVAs (21 in 3271 nbDMARD patients, 109 in 11 642 anti-TNF patients) had occurred during 11 973 and 61 226 person-years of observation, respectively (incidence rate 175 vs 178 per 100 000 person-years). After adjustment for confounders, there was no association between ever exposure to anti-TNF and ischaemic CVA risk (hazard ratio 0·88 [95% CI 0·46–1·71]). InterpretationExposure to anti-TNF therapy does not appear to be associated with risk of ischaemic CVA when compared with nbDMARD therapy. Further follow-up is needed to assess time-varying risk. FundingBritish Society for Rheumatology.