Rheumatoid arthritis and the risk of ischaemic stroke after diagnosis of atrial fibrillation: a Norwegian nationwide register study.

objectivesRA patients have an increased risk for cardiovascular diseases, including atrial fibrillation (AF), but the impact of RA on ischaemic stroke risk in the context of AF remains unknown. We explored whether the risk of ischaemic stroke after diagnosis of AF is further increased among patients with RA compared with non-RA patients.

methodsIn the nationwide Norwegian Cardio-Rheuma Register, we evaluated cumulative incidence and hazard rate of ischaemic stroke after the first AF diagnosis (2750 individuals with RA and 158 879 without RA between 2010 and 2017) by using a competing risk model with a 3-month delayed entry.

resultsThe 5-year unadjusted cumulative incidence of ischaemic stroke was 7.3% (95% CI: 5.9-8.7%) for patients with RA and 5.0% (95% CI: 4.9-5.2%) for patients without RA. Unadjusted univariate analyses indicated that AF patients with RA had a HR of 1.36 (95% CI: 1.13, 1.62) for ischaemic stroke compared with those without RA. Sex- and age-adjusted HR for ischaemic stroke in RA patients with AF was 1.25 (95% CI: 1.05, 1.50), and the effect size remained unchanged after adjustment for diabetes, hypertension, atherosclerotic cardiovascular disease and oral anticoagulant (OAC) treatment. RA patients were less likely to receive OAC treatment than non-RA patients (adjusted odds ratio 0.88, 95% CI: 0.80, 0.97).

conclusionRA patients diagnosed with AF are at a further increased risk for stroke compared with non-RA patients with AF, and less likely to receive OAC treatment, emphasizing the need to improve stroke prevention in AF patients with RA.