Moreover, key clinical outcomes are modestly, but significantly, better than with warfarin, as demonstrated in a recent meta-analysis of three pivotal randomized clinical trials of dabigatran, rivaroxaban, and apixaban involving nearly 45,000 patients. Compared with warfarin, the new agents collectively showed reductions of 22% in the risk of stroke or systemic embolism, 13% in the risk of vascular mortality, 12% in all-cause mortality, and 51% in intracranial hemorrhage, all of which were significant. In addition, there were nonsignificant trends for less major bleeding and more GI bleeding (Am. J. Cardiol. 2012;110:453-60).
Nonetheless, Dr. Hassell isn’t prepared to routinely substitute the new agents for warfarin. She’s waiting to see reports of more extensive experience with them in everyday clinical practice. For the time being, the patients in her practice who get one of the new anticoagulants instead of warfarin are those with normal renal function, low bleeding risk, unstable INRs on warfarin, and reasonably good medication adherence, and who are not taking any of the interacting drugs.
She sticks with warfarin in patients with a GFR below about 60 mL/minute or a stable INR in therapeutic range a great deal of the time. If they’re at high bleeding risk they get warfarin, which is readily reversible, unlike the novel anticoagulants. If they have problems with adherence, warfarin is the best option because missing a dose of warfarin causes less harm; loss of activity occurs within 12-24 hours with the new agents. And if Dr. Hassell thinks she wants to monitor the degree of anticoagulation by measuring INR, as in a patient with a history of multiple bleeding or clotting events, warfarin is the sole option.
She reported having no financial conflicts.