Use of Direct Oral Anticoagulants in Canadian Primary Care Practice 2010–2015: A Cohort Study From the Canadian Primary Care Sentinel Surveillance Network

Abstract

BackgroundAs questions have been raised about the appropriateness of direct oral anticoagulant (DOAC) dosing among outpatients with atrial fibrillation, we examined this issue in patients being managed by primary care providers.Methods and ResultsThis was a retrospective cohort new‐user study using electronic medical records from 744 Canadian primary care clinicians. Potentially inappropriate DOAC prescribing was defined as prescribing lower or higher doses than those recommended by guidelines for patients with nonvalvular atrial fibrillation. Of the 6658 patients with nonvalvular atrial fibrillation who were prescribed a DOAC (mean age: 74.8; 55% male), 626 (9.4%) had a CHADS 2 score of 0, and 168 (2.5%) had a CHADS‐VASc score of 0. Of the DOAC prescriptions, 527 (7.7%) were deemed potentially inappropriate: 496 (7.2%) were potentially underdosed, and 31 (0.5%) were prescribed a dose that was higher than recommended. Patients were more likely to be prescribed lower‐than‐recommended doses if they were female (adjusted odds ratio [aOR]: 1.3 [95% confidence interval (CI), 1.0–1.5]), had multiple comorbidities (aOR: 1.4 [95% CI, 1.1–1.8])—particularly heart failure (aOR: 1.6 [95% CI, 1.2–2.0]) or dementia (aOR: 1.4 [95% CI, 1.1–1.8])—or if they were also taking aspirin (aOR: 1.7 [95% CI, 1.3–2.1]) or nonsteroidal anti‐inflammatory drugs (aOR: 1.2 [95% CI, 1.02–1.5]). Potentially inappropriate DOAC dosing was more common in rural practices (aOR: 2.1 [95% CI, 1.7–2.6]) or smaller practices (aOR: 1.9 [95% CI, 1.6–2.4] for practices smaller than median).ConclusionsThe vast majority of DOAC prescriptions in our cohort of primary care–managed patients appeared to be for appropriate doses, particularly since prescribing a reduced dose of DOAC may be appropriate in frail patients or those taking other medications that predispose to bleeding.

Inappropriate direct oral anticoagulant dosing in atrial fibrillation patients is associated with prescriptions for outpatients rather than inpatients: a single-center retrospective cohort study

“…In a real-world registry in Spain, the rate of underdosing and overdosing of DOAC therapy was 17.5% (93/530) and 14.9% (79/ 530), respectively [16]. Other retrospective studies conducted abroad indicate that 5.4-17.4% patients are prescribed inappropriate reduced doses of DOACs (Additional file 1: Table S2) [17][18][19][20]. In our study, it was found that the rate of underdosing has been decreasing every year.…”

Exploring discrepancies between pharmacists’ perceived and actual roles towards optimising care in patients prescribed direct oral anticoagulants: a survey

“…refills every 1–3 months vs renal function assessment every 3–12 months depending on baseline renal function), the pharmacist may not be seeing the patients at point of refill and some pharmacists may perceive this as duplicating a task performed by the physician. However, real‐world evidence shows that approximately 10% of patients prescribed DOACs are receiving an inappropriate dose, including excess dosing in 43% of patients with a renal indication for a lower dose . This inappropriate dosing was associated with a greater risk of harm, including major thrombotic and bleeding events .…”

“…However, real-world evidence shows that approximately 10% of patients prescribed DOACs are receiving an inappropriate dose, including excess dosing in 43% of patients with a renal indication for a lower dose. [4][5][6] This inappropriate dosing was associated with a greater risk of harm, including major thrombotic and bleeding events. 5 These observations highlight a key role for pharmacists to improve patient outcomes.…”

“…Pharmacists can play a significant role in optimising DOAC use, including providing education to patients, assessing patients for optimal drug and dose, and ensuring ongoing monitoring for effectiveness, safety and adherence. Furthermore, the dosing of these agents depends on indication and renal function, and several studies have demonstrated that inappropriate dosing of DOACs is common in practice, indicating that pharmacists could play a key role in ensuring ongoing laboratory monitoring and reassessment of appropriateness of use . The aim of the present study was to explore community‐based pharmacists’ self‐reflection on several domains involved in optimising the management of patients prescribed DOACs.…”

“…Furthermore, the dosing of these agents depends on indication and renal function, and several studies have demonstrated that inappropriate dosing of DOACs is common in practice, indicating that pharmacists could play a key role in ensuring ongoing laboratory monitoring and reassessment of appropriateness of use. [4][5][6] The aim of the present study was to explore community-based pharmacists' self-reflection on several domains involved in optimising the management of patients prescribed DOACs.…”