Adherence, persistence to oral anticoagulants in first year of treatment suboptimal

Adherence and persistence to oral anticoagulants (OACs) the first year of treatment appear to be relatively low across drugs, a study has found.

Researchers looked at time trends at individual and system levels, as well as the risk factors for and associations between adherence and persistence, using data from the UK primary care EHR (The Health Information Network 2011–2016).

The analysis included 36,652 individuals with incident atrial fibrillation, cardiovascular comorbidities (median CHA₂DS₂VASc [Congestive heart failure, Hypertension, Age≥75 years, Diabetes mellitus, Stroke, Vascular disease, Age 65–74 years, Sex category], 3) and polypharmacy (median number of drugs, 6).

Adherence rates at 1 year after treatment initiation were 55.2 percent (95 percent confidence interval [CI], 54.6–55.7) for all OACs, 51.2 percent (95 percent CI, 50.6–51.8) for vitamin K antagonist (VKA), 66.5 percent (95 percent CI, 63.7–69.2) for dabigatran, 63.1 percent (95 percent CI, 61.8–64.4) for rivaroxaban and 64.7 percent (95 percent CI, 63.2–66.1) for apixaban.

One-year persistence rates were 65.9 percent (95 percent CI, 65.4–66.5) for all OACs, 63.4 percent (95 percent CI, 62.8–64.0) for VKA, 61.4 percent (95 percent CI, 58.3–64.2) for dabigatran, 72.3 percent (95 percent CI, 70.9–73.7) for rivaroxaban and 78.7 percent (95 percent CI, 77.1–80.1) for apixaban.

Nonadherence and nonpersistence increased over time at individual and system levels. Increasing comorbidity was associated with a lower likelihood of nonadherence and nonpersistence across all OACs.

Overall, the rate of ‘primary nonadherence’ (stopping after first prescription) was 3.5 percent, ‘nonadherent nonpersistence’ 26.5 percent and ‘persistent adherence’ 40.2 percent. These rates varied across OACs.

The present data may help to better understand the determinants of adherence and persistence, and to design and target interventions to improve adherence and persistence together across drugs, according to the researchers.