Low DOAC Adherence Is Common

Although direct oral anticoagulant (DOAC) therapy can help lower risk of thromboembolic events, new study findings indicate that nearly one-third of patients prescribed DOACs do not maintain adherence above 80%.

As a result, DOAC-treated patients with lower treatment adherence often have an increased risk of thromboembolic events compared with DOAC-treated and warfarin-treated patients with high adherence.
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Researchers arrived at this conclusion following a study of 52,365 warfarin-treated patients and 67,686 DOAC-treated patients. Administrative claims data for warfarin and DOAC prescriptions were obtained from IBM Watson Health Market Scan databases.

The researchers compared outcomes among patients with high adherence (at least 80% of days) or low adherence (40% to 80% of days) to DOACs or warfarin. Outcomes included hospitalization for thromboembolic events—including ischemic stroke or systemic embolism—as well as hemorrhagic stroke and major bleeding.

A Cox proportional-hazards model was implemented to account for basic patient characteristics, comorbidities, and a time-dependent covariate for anticoagulation based on prescription dosage.

Approximately 47% of warfarin-treated patients and 31% of DOAC-treated patients demonstrated lower treatment adherence. Results of the study revealed that warfarin-treated patients and DOAC-treated patients with lower adherence had 48% and 69% higher risks for thromboembolic events, respectively, compared with warfarin-treated patients with higher adherence.

In contrast, DOAC-treated patients with higher treatment adherence were 14% less likely to experience thromboembolic events compared with warfarin-treated patients with higher adherence.

“[Patients] with lower adherence may be candidates for device therapies that obviate the need for chronic [anticoagulation],” the researchers wrote.

These findings were presented at the Heart Rhythm Scientific Sessions in Boston, Massachusetts.

—Christina Vogt

Reference:

Lakkireddy DR, Karst E, Mahapatra S, et al. Lower adherence direct oral anticoagulants use is associated with increased risk of thromboembolic events than warfarin – understanding the real-world performance of systemic anticoagulation in atrial fibrillation. Paper presented at: Heart Rhythm Scientific Sessions; May 9-12, 2018; Boston, MA. http://abstractsonline.com/pp8/ - !/4554/presentation/7923