One in Ten Patients with Atrial Fibrillation Fail to Fill Initial DOAC Prescription

Primary nonadherence with anticoagulant therapy may be influenced by which DOAC is prescribed, age, and diagnosis of several chronic diseases, a new study found.

Direct oral anticoagulant prescriptions unfilled by 10% of patients

One in ten patients with nonvalvular atrial fibrillation (NVAF) prescribed direct oral anticoagulants (DOACs) failed to collect a first prescription, according to a new study published in the Journal of Managed Care + Specialty Pharmacy.

Risk of stroke among patients with NVAF is high, according to study authors, and anticoagulation therapy, increasingly with DOACs (vs vitamin K agonists) is commonly prescribed following a diagnosis. The clinical implications of DOAC nonadherence are significant, they stress, but few studies have explored primary nonadherence, ie, failure to fill a first prescription. The majority of drug utilization research, they point out, focuses on other adherence measures, such as discontinuation, persistence, or medicine possession ratio.

More information on the point at which nonadherence begins, the authors write, may help identify primary areas for intervention.

Drawing on a pharmacy claims database that contains primary care details for approximately 80% of the population of Catalonia, Spain, the team, led by Alethea Charlton, MPharm, with Hospital Vall d’Hebron in Spain, identified 12 257 patients with an ICD-10 diagnosis of NVAF who were prescribed a DOAC for the first time between January 2009 to December 2015.

The mean patient age was 74.6 years with the largest age group being at least 80-years-old (37.9%). The majority (53.6%) were men.

Overall primary nonadherence was found to be 10.4%. More specifically, the authors report, apixaban was associated with the highest rate of primary nonadherence (12.8%) followed by rivaroxaban (10.8%) and dabigatran (8.6%).

The researchers found that nonadherence was more common among those younger than age 65 years.

Among the patients who failed to collect a first DOAC prescription there was a higher prevalence of chronic kidney disease. Prevalence of other chronic conditions in this group was lower: diabetes, 25.9% vs 29.6%; hypertension, 67.4% vs 73.2%; other CV disease, 19.7% vs 22.4%; and, stroke/TIA, 16.2% vs 22.3%.

The authors point to the potential for DOAC nonadherence to impact the cost-effectiveness of prescribing the drugs and express concern that the effect on patient outcomes of failure to initiate treatment with the medications has yet to be quantified.

The overall results, including factors identified that may influence primary nonadherence, “highlight a key opportunity to design interventions targeting primary nonadherence,” wrote Charlton and colleagues. "Moreover, primary nonadherent patients may never visit the community pharmacies where many adherence interventions currently take place.”

Reference: Charlton A, Vidal Z, Sabaté M, et al. Factors associated with primary nonadherence to newly initiated direct oral anticoagulants in patients with nonvalvular atrial fibrillation. J Manag Care Spec Pharm. 2021;27:1210-1220.

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