Anticoagulating atrial fibrillation patients: is there a kidney-friendly choice?

Atrial fibrillation is the most common sustained arrhythmia that will increase the risk of ischemic stroke, systemic thromboembolism as well as mortality. Reduced kidney function and albuminuria are independently associated with higher incidence of atrial fibrillation (1). Without anticoagulation, the risk of thromboembolism is greater with more severe proteinuria and lower estimated glomerular filtration rate (eGFR), according to a follow-up study of the observational ATRIA (Anticoagulation and Risk Factors in Atrial Fibrillation) cohort (2). Warfarin has been the mainstay of oral anticoagulation therapy since 1954. An observational study using Danish nationwide registries reviewed discharged patients with non-valvular atrial fibrillation from 1997 to 2008, during which the prevalence of renal disease increased from 3.4% to 7.0%. Warfarin was less frequently prescribed in patients with chronic kidney disease (CKD) (17.0%) or receiving renal replacement therapy (RRT) (19.8%) than in those without renal disease (28.6%). Warfarin reduced the risk of stroke or systemic thromboembolism in patients on RRT in this study. However, warfarin was associated with a ~30% increase in the bleeding risk in general, and bleeding occurred more frequently in CKD and RRT groups (3). In another population-based cohort study enrolling patients aged ≥66 years and eGFR <45 mL/min/1.73 m2, warfarin did not lower the risk of stroke, but a significantly higher risk of bleeding was observed (4). The net clinical benefit of anticoagulation in patients with moderate to severe CKD, including end-stage renal disease (ESRD), is still controversial and requires careful patient selection