Medication adherence to direct oral anticoagulants: extent and impact of
side effects
Abstract
Aim Recent studies have shown that good adherence cannot be taken for
granted for patients on direct anticoagulants (DOACs). In this
cross-sectional study, adherence among DOAC users was investigated and
associations between beliefs about medication, perceived side effects
and adherence were investigated. Methods We included 100 randomly
selected adult DOAC users visiting one of the two participating Dutch
community pharmacies in the summer of 2020. The self-reported adherence
(primary outcome) was assessed with the Medication Adherence Rating
Scale-5 (MARS-5). Beliefs about DOACs were assessed with the Beliefs
about Medicine Questionnaire Specific (BMQ-S) while side effects were
assessed with a self-developed questionnaire based on the Lareb
Intensive Monitoring (LIM) system. Results Of the participants, 9%
reported non-adherence on the MARS-5 (score <24). Associations
were found between non-adherence and both reported side effects and side
effect burden. Furthermore patients’ belief that DOACs have unpleasant
side effects was associated with both non-adherence and more
side-effects. No associations were found between adherence and either
gender, indication, DOAC or dosage. Conclusion This study confirms that
non-adherence in patients on DOACs is prevalent. We recommend that both
physicians and pharmacists evaluate adherence and side effects with
their DOAC patients on a regular base.