Balancing Stroke and Bleeding Risks in Patients With Atrial Fibrillation and Renal Failure: the Swedish Atrial Fibrillation Cohort Study

Study Questions:

Does warfarin provide net benefit in patients with atrial fibrillation (AF) and renal failure (RF)?


The data in this retrospective study of 283,969 patients with AF were obtained by analysis of health care databases in Sweden. RF was present in 13,435 patients (4.7%), and 3,766 of these patients (28%) were taking warfarin at baseline. Outcomes were tracked over a median follow-up of 2.1 years.


The annual ischemic stroke rate was higher in patients with (3.9%) than without (2.9%) RF, but after adjustment for cofactors, RF was not independently associated with an excess risk of stroke. The annual rate of intracranial bleeds was significantly higher in patients with (0.8%) than without (0.5%) RF, and RF was an independent risk factor for intracranial bleeds (hazard ratio [HR], 1.27). RF also was an independent risk factor for all-cause mortality (HR, 1.6). Warfarin reduced the risk of ischemic stroke to a similar extent in patients with (HR, 0.69) and without (HR, 0.70) RF. Warfarin tended to increase the risk of intracranial bleeding to a greater degree in patients with (HR, 1.56) than without (1.29) RF, but the interaction between warfarin and RF was not significant. For the composite endpoint of ischemic stroke, intracranial bleeding, or death, warfarin exerted a greater benefit in patients without (HR, 0.63) than with (0.74) RF.


Although the degree of benefit is attenuated, patients with AF and RF still derive a net benefit from anticoagulation with warfarin.


Given that RF increases the risk of major bleeding, it is reassuring to know that warfarin nevertheless does more good than harm in patients with AF and RF.

Clinical Topics: Anticoagulation Management

Keywords: Stroke, Renal Insufficiency, Intracranial Hemorrhages, Sweden, Warfarin, Risk Factors

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