Balancing stroke and bleeding risks in patients with atrial fibrillation and renal failure: the Swedish Atrial Fibrillation Cohort study

Background Patients who have both atrial fibrillation (AF) and renal failure have an increased risk of thrombo-embolism. Renal failure is also a risk factor for bleeding, which makes decisions regarding thromboprophylaxis complicated. Our aim was to determine risks for ischaemic stroke and bleeding in patients with AF and renal failure in relation to anticoagulant strategies. Methods and results This is retrospective non-randomized study of Swedish health registers comprising 307 351 patients with AF, of whom 13 435 had a previous diagnosis of renal failure. Ischaemic stroke occurred more often in AF patients with renal failure (annual rate, 3.9% vs. no renal failure, 2.9%), but this was related to concomitant comorbidities [adjusted hazard ratio (HR) 1.02, 95% confidence interval (CI) 0.95-1.10]. Adding renal failure to the established stroke risk stratification schemes (CHADS(2) and CHA(2)DS(2)-VASc) did not improve their predictive value. Renal failure was an independent risk factor for intracranial bleeding [adjusted HR: 1.27 (1.09-1.49)]. Most patients with renal failure benefited from warfarin treatment, despite their high bleeding risk. The incidence of the combined endpoint ischaemic or haemorrhagic stroke or death was lower among those who used warfarin than among those who did not use warfarin (adjusted HR: 0.76, CI 0.72-0.80). Conclusions Patients with both AF and renal failure will probably benefit most from having the same treatment as is recommended for other patients with AF, without setting a higher or lower threshold for treatment. Adding additional points for renal failure to the CHADS(2) and CHA(2)DS(2)-VASc scores did not improve their predictive value.