Prescriptions for novel oral anticoagulants in Canada have increased rapidly since their approval for the treatment of atrial fibrillation, particularly among patients aged 85 years or older, according to a recent report.
Researchers performed a time-series analysis of prescriptions of dabigatran (Pradaxa, Boehringer Ingelheim), rivaroxaban (Xarelto, Janssen Pharmaceuticals) and warfarin between October 2010 and September 2012 among patients in Ontario aged 20 years or older. Data on dabigatran prescriptions were stratified according to age, and the proportion administered to patients aged older than 65 years was compared with that observed in the RE-LY study.
In September 2012, novel anticoagulants accounted for 21.1% of all prescribed oral anticoagulants per month (17.2% dabigatran, 3.9% rivaroxaban), reflecting a more than 20-fold increase in frequency during the course of the study. Researchers attributed this change primarily to an increase in dabigatran prescriptions: from three per 100,000 people to 274 per 100,000 people (P<.001). The number of warfarin prescriptions per month decreased significantly during the study period, from 1,526 per 100,000 people to 1,316 per 100,000 people (P=.007).
Patients aged 85 years or older had the highest rates of dabigatran prescription, with 93.6% of that age group and 58.8% of those aged 65 to 84 years receiving the lower dose of 110 mg per day. A significantly greater proportion of patients aged 65 years and older had filled prescriptions for dabigatran since April 2012 compared with participants who were enrolled in the dabigatran arms in the RE-LY study (87.3% vs. 83.2%; P<.001).
The oldest age group also received the greatest proportion of prescriptions when analysis was limited to only new dabigatran prescriptions, rather than refills.
“We observed rapid growth in the uptake of the novel oral anticoagulants, in particular dabigatran within the 2 years after its approval for use in patients with atrial fibrillation,” the researchers concluded. “… Growth in the uptake of novel oral anticoagulants in very old patients, a group at high risk of bleeding, signals the need to evaluate outcomes in clinical practice to better guide the use of these agents.”
Disclosure: See the full study for a list of relevant financial disclosures.