Adherence to and persistence with direct oral anticoagulant therapy among patients with new onset venous thromboembolism receiving extended anticoagulant therapy and followed by a centralized anticoagulation service.

BACKGROUND

Extended direct oral anticoagulant (DOAC) therapy may be required for patients with a venous thromboembolism (VTE); thus, DOAC adherence may impact the risk of recurrent VTE or bleeding.

MATERIALS AND METHODS

This was a retrospective cohort study. Adult patients with a VTE who were initiated on a DOAC between January 1, 2010 and December 31, 2017 for a cumulative >90 days of therapy were included. Adherence, measured with the proportion of days covered (PDC), was assessed during the six, 12, and 18 months after initiation. Patients were assigned to PDC ≥ 80% (adherent) or PDC < 80% (non-adherent) groups during the 1- to 6-month follow-up period. Rates of recurrent VTE and hemorrhagic events were compared between the groups.

RESULTS

A total of 305 patients were included. The mean PDC were 96.0% (±8.0%), 94.7% (±8.2%), and 94.4% (±7.7%) during the 6-, 12-, and 18-month follow-ups, respectively, with 17 (5.6%) and 288 (94.4%) patients classified as non-adherent and adherent, respectively. Patients in the non-adherent group were more likely to have had a recurrent VTE during the 1- to 6-month (11.8% vs. 1.0%, p = 0.007) and 1- to 12-month follow-ups (16.6% vs. 3.6%, p = 0.030). There were no statistically significant differences between the groups in the rates of bleeding during any follow-up periods (all p > 0.05).

CONCLUSIONS

In patients who had >90 days of initial DOAC therapy, adherence to DOAC therapy was high throughout the 18-month follow-up while DOAC non-adherence (i.e., PDC < 80%) increased the risk of recurrent VTE.