Clinical effects of off-label reduced doses of Direct Oral Anticoagulants: A systematic review and meta-analysis

Direct-Acting Oral Anticoagulants and Potential Inconsistencies with FDA-Approved Dosing for Non-Valvular Atrial Fibrillation: A Retrospective Real-World Analysis Across Nine US Healthcare Systems

BACKGROUND

Direct-acting oral anticoagulants (DOACs) are recommended to reduce risk of stroke and systemic embolism in patients with non-valvular atrial fibrillation (NVAF). However, DOAC dosing inconsistent with FDA-approved product labels is common and associated with poor clinical outcomes.

OBJECTIVES

Identify DOAC dosing inconsistent with FDA-approved product labels in ambulatory care patients with NVAF; identify variables associated with dosing lower and higher than label.

DESIGN

Retrospective analysis using electronic health records from nine US healthcare systems.

PATIENTS

Adults with NVAF receiving DOAC therapy in 2022.

MAIN MEASURES

Rates of label-inconsistent dosing; multivariable regression analysis to identify demographic and clinical variables associated with dosing lower and higher than label.

KEY RESULTS

Among 51,128 NVAF patients (56.1% male, 94.3% White, mean [SD] age 73.5 [10.5] years), 5008 (9.8%) were prescribed label-inconsistent doses of DOACs (6.8% lower and 3.0% higher than label). Age ≥ 75 years, renal impairment, and hypertension were significantly associated with inconsistent dosing both higher and lower than label. Female sex and higher weight were significantly associated with dosing lower than label, as were heart failure, vascular or liver disease, and bleeding history. Dosing higher than label was significantly associated with male sex, race (African American/Black), weight < 60 kg, and use of drugs with potential drug-drug interactions. When prescribed by primary care physicians, DOAC doses were 37% (95% CI, 27-49%) more likely to be lower than label and 30% (95% CI, 16-46%) more likely to be higher than label than when prescribed by cardiologists or electrophysiologists. Label-inconsistent dosing varied (6.7 to 15.8%) across participating systems.

CONCLUSIONS

DOAC dosing inconsistent with label varied by demographics, clinical characteristics, prescriber specialty, and healthcare system, suggesting a need to monitor and assess dosing decisions in NVAF. Identification of variables associated with dosing inconsistencies may enable targeted interventions to ensure label-consistent dosing in vulnerable populations.

Dose Reduction of Edoxaban in Patients 80 Years and Older With Atrial Fibrillation: Post Hoc Analysis of the ENGAGE AF-TIMI 48 Randomized Clinical Trial

Importance

In older patients with atrial fibrillation who take anticoagulants for stroke prevention, bleeding is increased compared with younger patients, thus, clinicians frequently prescribe lower than recommended doses in older patients despite limited randomized data.

Objective

To evaluate ischemic and bleeding outcomes in patients 80 years and older with atrial fibrillation receiving edoxaban, 60 mg vs 30 mg, and edoxaban, 30 mg vs warfarin.

Design, Setting, and Participants

The ENGAGE AF-TIMI 48 trial (Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis in Myocardial Infarction 48) was a parallel-design, double-blind, global clinical trial that randomized patients with atrial fibrillation to either one of 2 edoxaban dosing regimens or warfarin. This secondary analysis focused on patients 80 years or older without dose-reduction criteria receiving edoxaban, 60 mg vs 30 mg, as well as patients with or without dose-reduction criteria receiving edoxaban, 30 mg, vs warfarin. Study data were analyzed between October 2022 and December 2023.

Interventions

Oral edoxaban, 30 mg once daily; edoxaban, 60 mg once daily; or warfarin.

Main Outcomes and Measures

Primary net clinical outcome of death, stroke or systemic embolism, and major bleeding and each individual component.

Results

The current analysis included 2966 patients 80 years and older (mean [SD] age, 83 [2.7] years; 1671 male [56%]). Among 1138 patients 80 years and older without dose-reduction criteria, those receiving edoxaban, 60 mg vs 30 mg, had more major bleeding events (hazard ratio [HR], 1.57; 95% CI, 1.04-2.38; P = .03), particularly gastrointestinal hemorrhage (HR, 2.24; 95% CI, 1.29-3.90; P = .004), with no significant difference in efficacy end points. Findings were supported by analyses of endogenous factor Xa inhibition, a marker of anticoagulant effect, which was comparable between younger patients receiving edoxaban, 60 mg, and older patients receiving edoxaban, 30 mg. In 2406 patients 80 years and older with or without dose-reduction criteria, patients receiving edoxaban, 30 mg, vs warfarin had lower rates of the primary net clinical outcome (HR, 0.78; 95% CI, 0.68-0.91; P = .001), major bleeding (HR, 0.59; 95% CI, 0.45-0.77; P < .001), and death (HR, 0.83; 95% CI, 0.70-1.00; P = .046), whereas rates of stroke or systemic embolism were comparable.

Conclusions and Relevance

In this post hoc analysis of the ENGAGE AF-TIMI 48 randomized clinical trial, in patients 80 years and older with atrial fibrillation, major bleeding events were lower in patients randomized to receive edoxaban, 30 mg per day, compared with either edoxaban, 60 mg per day (in patients without dose-reduction criteria), or warfarin (irrespective of dose-reduction status), without an offsetting increase in ischemic events. These data support the concept that lower-dose anticoagulants, such as edoxaban, 30 mg, may be considered in older patients with atrial fibrillation even in the absence of dose-reduction criteria.

Trial Registration

ClinicalTrials.gov Identifier: NCT00781391.

Comparative Effectiveness and Safety of Off-Label Underdosed Direct Oral Anticoagulants in Asian Patients with Atrial Fibrillation: A Systematic Review and Meta-analysis

INTRODUCTION

Off-label underdosed direct oral anticoagulants (DOACs) are commonly utilised in Asian patients with atrial fibrillation (AF) since they are prone to bleeding with OACs. However, the efficacy and safety of off-label underdosing DOACs are controversial. This study aimed to compare the effectiveness and safety of off-label underdosed DOACs in Asian patients with AF.

METHODS

PubMed, Embase, Cochrane library, and ClinicalTrials.gov were searched from 2010 to July 5, 2024, for randomised controlled trials or observational studies that compared off-label DOACs and on-label/warfarin in Asian patients with AF. The primary outcomes included ischaemic stroke or systemic embolism (ISSE) and major bleeding (MB), while secondary outcomes included all-cause death, gastrointestinal bleeding (GIB), intracranial haemorrhage (ICH), and myocardial infarction (MI). Hazard ratios (HRs) with 95% confidence intervals (CIs) were pooled using random-effects models.

RESULTS

Twenty observational studies were included. Seventeen studies compared off-label underdosed DOACs versus on-label DOACs, whereas five studies compared off-label underdosed DOACs versus warfarin. Off-label underdosed DOACs were associated with higher risk of ISSE (pooled HR [pHR] = 1.17; 95% CI: 1.00-1.38, p = 0.048) and ICH (pHR = 1.27; 95% CI: 1.06-1.52, p = 0.010) versus on-label. Subgroup analysis demonstrated increased ISSE risk with off-label underdosed rivaroxaban compared to on-label (pHR = 1.49; 95% CI: 1.07-2.08). Compared to warfarin, off-label underdosed DOACs were associated with decreased risk of MB (pHR = 0.46; 95% CI: 0.32-0.65, p < 0.001), GIB (pHR = 0.52; 95% CI: 0.29-0.93, p = 0.028), ICH (pHR = 0.60; 95% CI: 0.42-0.86, p = 0.005), and all-cause death (pHR = 0.70; 95% CI: 0.56-0.87, p = 0.001), while illustrating similar ISSE risk.

CONCLUSIONS

Off-label underdosed DOACs, particularly rivaroxaban, was associated with increased ISSE risk but did not decrease bleeding compared to on-label. Adherence to appropriate DOAC doses should be emphasised to achieve the best clinical outcomes for Asian patients with AF.

Inappropriate prescriptions of direct oral anticoagulants (DOACs) in hospitalized patients: A narrative review

Direct oral anticoagulants (DOACs) have become the cornerstone for prevention of thromboembolic events in patients with atrial fibrillation and patients with a history of venous thromboembolism. However, studies show that DOAC prescriptions are commonly inconsistent with guideline recommendations. DOAC dosing in the acutely ill patient could impose an even greater challenge. In this review, we describe the prevalence of inappropriate inpatient prescribing of DOACs and the associated rationales, predictors and clinical consequences. With the aim of promoting appropriate prescriptions of DOACs to hospitalized patients, we further outline DOAC dose reduction criteria justified by various guidelines, illustrating the complexities of appropriate dosing, especially in acutely ill patients. Moreover, we will discuss the impact of anticoagulant stewardship programs and the vital role that pharmacists may play in optimizing inpatient DOAC treatment.

A Descriptive Analysis of Direct Oral Anticoagulant Drugs Dosing Errors Based on Spontaneous Reports from the EudraVigilance Database

Direct oral anticoagulant drugs (DOACs) interfere with the coagulation process, thus improving patient care for those who require anticoagulant treatment. This study presents a descriptive analysis of adverse reactions (ADRs) attributed to DOAC dosage errors (overdose, underdose, and improper dose). The analysis was performed based on the Individual Case Safety Reports from the EudraVigilance (EV) database. Results show that data reported for rivaroxaban, apixaban, edoxaban, and dabigatran are mostly regarding underdosing (51.56%) compared to overdosing (18.54%). The most dosage error reports were identified for rivaroxaban (54.02%), followed by apixaban (33.61%). Dabigatran and edoxaban had similar percentages (6.26% and 6.11%, respectively) regarding dosage error reports. Since coagulation issues can become life-threatening events, and factors such as advanced age and renal failure can influence the pharmacokinetics of drugs, the correct usage of DOACs is of utmost importance for the management and prevention of venous thromboembolism. Thus, the collaboration and the complementarity of knowledge of physicians and pharmacists may offer a reliable solution for DOAC dose management and improve patient care.

Safety and efficacy of direct oral anticoagulants in geriatric patients with non-valvular atrial fibrillation: A single-center retrospective study

INTRODUCTION

Direct oral anticoagulants (DOACs) are widely employed for antithrombotic prophylaxis in patients with atrial fibrillation (AF). However, there is still uncertainty about their risk-benefit profile in older patients. Here, we evaluated the efficacy, safety, and dose appropriateness of DOACs in a real-world population of outpatients with non-valvular AF, with a specific focus on subjects aged over 80 years and/or with reduced renal function.

MATERIALS AND METHODS

Single-center retrospective study including patients who had been prescribed a DOAC between May 2014 and May 2021 for long-term anticoagulation in non-valvular AF. Patients anticoagulated for <4 weeks were excluded. The primary efficacy outcome was a composite of cardiovascular (CV) death, stroke, or systemic embolism. The primary safety outcome was major bleeding.

RESULTS

A total of 1154 patients (median age 84 yrs., range 57-100 yrs.), among which 862 were 80 years and older, were included. In the subgroup of subjects ≥80 yrs., a subtherapeutic dose of DOAC was associated with an increased incidence of CV mortality, stroke, or systemic embolism (multivariable Cox regression, HR = 2.09, 95 % CI: 1.09-4.02), with no benefit in terms of prevalence of bleeding events (21.5 % vs. 18.6 %, p = 0.428), and the incidence of adverse safety and efficacy outcomes was not increased in patients with a reduced renal function (eGFR ≤30 mL/min). Plasma concentration of DOACs, assessed in a subset of 367 patients, did not increase with advanced age (≥ 80 yrs., two-way ANOVA, p = 0.656) nor with declining eGFR (≤30 mL/min, two-way ANOVA, p = 0.643) and was not associated with adverse safety and efficacy outcomes.

CONCLUSIONS

Data from our study support the use of DOACs in populations of older adults and remark on the risks associated with inappropriate prescriptions in terms of CV mortality and adverse events.

Managing antithrombotic treatment in a patient with atrial fibrillation and coronary stent with transient neurological symptoms in cerebral amyloid angiopathy

We present the antithrombotic dilemma in a case with atrial fibrillation and a coronary stent and suspected transient ischemic attacks after diagnosed as a probable cerebral amyloid angiopathy and discuss plausible treatment options for the patient based on the available evidence.