What does this research mean for the field?

Inappropriate dosing of direct oral anticoagulants occurs in 18% of patients with atrial fibrillation, with older age and higher CHA2DS2VASc scores acting as independent predictors, while nearly half of low-dose prescriptions are inappropriately underdosed. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

October 1, 2023EP EuropaceOpen Access

Characteristics of patients with atrial fibrillation treated with direct oral anticoagulants and new insights into inappropriate dosing: results from the French National Prospective Registry: PAFF

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Why the study?

Inappropriate and/or underdosing of DOACs for AF therapy has been a major clinical challenge since their introduction.

Structured PICO

Population

1,890 patients with atrial fibrillation receiving direct oral anticoagulants (DOACs) from the French National Prospective Registry (PAFF) between October 2021 and December 2021.

Intervention

Direct oral anticoagulants (apixaban 55%, dabigatran 7%, rivaroxaban 38%)

Comparator

Appropriate vs. inappropriate dosing

Outcome

Prevalence and predictors of inappropriate DOAC dosing

Inappropriate DOAC dosing remains common (18%) in real-world atrial fibrillation patients, with underdosing frequently driven by older age and perceived bleeding risk rather than objective renal impairment.

Implication

Alerts clinicians to verify DOAC doses in elderly AF patients; leaves open impact on outcomes and correction strategies.

Abstract

AIMS: Since the introduction of direct oral anticoagulant (DOAC) for atrial fibrillation (AF) therapy, inappropriate and/or underdosing of these drugs has been a major clinical challenge. We evaluated the characteristics of patients with AF treated with inappropriate and low-dose DOACs. METHODS AND RESULTS: Patients with AF treated with inappropriate and low-dose DOACs from October 2021 to December 2021 were evaluated from the French National Prospective Registry (PAFF). We evaluated 1890 patients with AF receiving DOACs (apixaban 55%, dabigatran 7%, and rivaroxaban 38%). Inappropriate dosing was noted in 18% of the population. Patients with appropriate dosing had less comorbidities: younger age (75 ± 10 vs. 82 ± 8 years old, P < 0.0001), reduced chronic renal failure (26 vs. 61%, P < 0.0001), and lower CHA2DS2VASc and HASBLED scores (3 ± 2 vs. 4 ± 3, P < 0.0001; 2 ±1 vs. 2 ± 2, P < 0.0001), respectively. In multivariate analysis, older age (P < 0.0001) and a higher CHA2DS2VASc score (P = 0.0056) were independently associated with inappropriate DOAC dosing. Among 472 patients (27%) treated with low-dose rivaroxaban or apixaban, 46% were inappropriately underdosed. Patients inappropriately underdosed were younger (82.3 ± 8.4 vs. 85.9 ± 5.9 years, P < 0.0001) with less chronic renal disease (47 vs. 98%, P < 0.0001). However, these patients had higher rates of prior haemorrhagic events (18 vs. 10%, P = 0.01), clopidogrel use (11 vs. 3%, P = 0.0002), and apixaban prescription (74 vs. 50%, P < 0.0001). CONCLUSION: Within this large registry, DOACs were associated with inappropriate dosing in 18% of cases. Independent predictors of inappropriate dosing were high CHA2DS2VASc scores and older age. Moreover, 46% of patients treated with low-dose DOACs were inappropriately underdosed and more frequently in patients treated with apixaban.