When the rubber meets the road: adherence and persistence with non-vitamin K antagonist oral anticoagulants and old oral anticoagulants in the real world-a problem or a myth ?

For patients taking vitamin K antagonist (VKA) anticoagulants, poor adherence to the drug regimen is associated with a lower percent time in therapeutic range and also with an increased risk of thromboembolic complications. The non-vitamin K antagonist oral anticoagulants (NOACs) do not require routine laboratory monitoring and therefore the risk of nonadherence remaining undetected and without any corrective attempts must be recognized. Persistence with the NOACs and VKA was quite comparable in the phase III trials, whereas a postmarketing study demonstrated better persistence with dabigatran than with warfarin. Preliminary studies on adherence to the dabigatran regimen have shown poor adherence in 12 to 27%, and also for this drug such behavior seems associated with an unfavorable outcome. There is uncertainty about the best methods to evaluate adherence. Studies on the adherence are needed for all the NOACs, for different clinical settings and patient populations. A combination of strategies should probably be used to achieve the best possible adherence, including patient education and some form of automatic reminders.