Are We Using Novel Oral Anticoagulants Wisely?

SOURCE: Barra ME, Fanikos J, Connors JM, et al. Evaluation of dose-reduced direct oral anticoagulant therapy. Am J Med 2016;129:1198-1204.

There is little dispute over whether the so-called novel oral anticoagulants (NOACs), currently comprised of apixaban, dabigatran, edoxaban, and rivaroxaban, are as efficacious as warfarin, as well as simpler to use, since food interactions are minimal.

NOACs individually include labeling that calls for potential dose adjustments for chronic kidney disease, low body weight, and interacting substances (agents with p-glycoprotein and/or P450 interactions). Have clinicians performed dose-adjustments appropriately?

Barra et al retrospectively analyzed data from 224 patients who had been prescribed reduced-dose NOACs to determine if the dose reductions had been according to appropriate indications (as per labeling) as well as appropriate in amount of dose reduction.

Less than half the patients who had been prescribed reduced-dose NOACs matched labeling criteria for such dose reduction. It may have been that concern over bleeding risk prompted prescribers to choose dose reduction; however, bleeding rates even within this group of patients receiving reduced-dose NOAC actually were higher than had been seen in clinical trials of NOACs.

How dose adjustment based on clinician judgment, as opposed to specific FDA labeling, will affect long-term outcomes remains to be determined.