Why switch from warfarin to NOACs?

Several patients with non-valvular atrial fibrillation treated with warfarin or other vitamin-K antagonists (VKA) might benefit from switching to an oral non vitamin-K antagonist anticoagulant (NOAC). In the absence of randomised comparative trials of switching to NOACs versus maintaining VKA treatment, several considerations argue in favour of a switching strategy. First, there is conclusive evidence that haemorrhagic strokes and intracranial bleedings are much fewer in number with NOACs than with warfarin. The risk of intracranial bleeding is 52 % lower with NOACS than with warfarin, with extremes ranging from 33 to 70 %. Such benefit is applicable to different NOACs, and independent of the time-in-therapeutic range under warfarin. Patients at increased risk for intra-cranial bleeding (renal dysfunction, or prior stroke or intra-cranial bleeding) should benefit most from switching to NOACs. Patients with labile International Normalized Ratio are also considered good candidates for switching because of their increased risk of stroke, and the lack of interactions between the effects of NOACs versus warfarin and the time-in-therapeutic range. Furthermore, some NOACs proved to be superior to warfarin in reducing the risk of thromboembolic complications even in intention-to-treat analyses. As further advantage, NOACs show fewer drug-drug and drug-food interactions when compared with warfarin. Last, but not least, NOACs do not need frequent blood drawings except in patients with moderate renal dysfunction, in whom periodic controls of serum creatinine are generally advised. The higher cost remains a barrier to a wider use of NOACs, especially in low-income settings.