Clinical Outcomes of Warfarin Initiation in Advanced Chronic Kidney Disease Patients With Incident Atrial Fibrillation

Abstract Objectives The aim of this study was to examine the efficacy and safety of warfarin initiation following the diagnosis of atrial fibrillation (AF) in patients with late-stage chronic kidney disease (CKD) who transitioned to dialysis. Background The clinical benefit of warfarin therapy for thromboprophylaxis after incident AF diagnosis in patients with late-stage CKD who are transitioning to dialysis is unknown. Methods In this retrospective cohort analysis, the study population was a national cohort of 22,771 U.S. veterans with incident end-stage renal disease who developed incident AF before initiating renal replacement therapy. This study examined the association of warfarin therapy following the diagnosis of incident AF with ischemic cerebrovascular accidents (CVAs) (ischemic stroke or transient ischemic attack), ischemic CVA−related hospitalization, major bleeding events (gastrointestinal or intracranial bleeding), bleeding event−related hospitalizations, and post-dialysis, all-cause mortality in multivariable adjusted Cox regression analyses that adjusted for demographic characteristics and comorbidities. Results The mean ± SD age of the cohort was 73.5 ± 8.8 years, 13% were African American, and the mean CHAD2S2-VASc score was 5.7 ± 2.1. Of the overall cohort, 6,682 (29.3%) patients were started on warfarin during the follow-up period. The hazard ratios (95% confidence intervals) for ischemic CVA, bleeding events, and death for those started on warfarin were 1.23 (1.16 to 1.30), 1.36 (1.29 to 1.44), and 0.94 (0.90 to 0.97), respectively, compared with those who received no anticoagulation. Warfarin exposure was associated with higher risk for ischemic CVA and bleeding event−related hospitalizations. Conclusions In patients with late-stage CKD who transitioned to dialysis, warfarin use was associated with higher risk of ischemic and bleeding events but a lower risk of mortality. Future studies such as those comparing warfarin with newer oral anticoagulant agents are needed to granularly define the net clinical benefit of anticoagulation therapy in patients with advanced CKD with incident AF.