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 ?

Abstract

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.

Frequency and Determinants of Adherence to Oral Anticoagulants in Stroke Patients with Atrial Fibrillation in Clinical Practice

“…In contrast to VKAs, NOACs allow for the ad-ministration of fixed doses without the need for routine coagulation monitoring [1,2] .…”

“…Without blood testing, patients' adherence to the NOAC regimen is not regularly monitored, raising concerns that NOAC patients might be prone to non-adherence [1] . Drug-specific tests gauging NOAC plasma levels are only available in specialized centers and, given the NOACs' short half-lives, would only provide information on adherence limited to the short period of a few hours prior to test [2,3] .…”

“…Drug-specific tests gauging NOAC plasma levels are only available in specialized centers and, given the NOACs' short half-lives, would only provide information on adherence limited to the short period of a few hours prior to test [2,3] . Non-adherence has been associated with an increased risk for ischemic complications [4] and full adherence is recommended [1,2] . The assessment of adherence and interventions for ensuring it have been proposed [1][2][3] .…”

Imaginary Worlds: The Status of Modeled Quality Adjusted Life Year Claims for New Oral Anticoagulants in Atrial Fibrillation Published Between January 2012 and February 2016

“…A recent assessment of rates of premature discontinuation in long-term NOAC clinical trials also points to a substantial proportion of patients discontinuing therapy prematurely 64 . Across ten long-term trials unscheduled cessation within the NOAC arm ranged from 11.3% to 34.4%, with discontinuation due to adverse events ranging from 1.7% to 17.2%.…”

Adherence to the novel oral anticoagulants: an unmet need

“…Finally, their use raises concerns about adherence to the prescribed treatment. Indeed, patients may have difficulty in remembering to take their medication without the requirement of blood monitoring, with the consequent loss of clinical effectiveness 9 . This is especially true for drugs such as dabigatran and apixaban, which require twice daily administrations.…”