Concomitant Use of Diltiazem With Direct Oral Anticoagulants and Bleeding Risk in Atrial Fibrillation

Potential interactions between medications for rate control and direct oral anticoagulants: population-based cohort and case-crossover study

BACKGROUND

Direct oral anticoagulants (DOACs) are commonly co-prescribed with amiodarone/diltiazem/verapamil, but whether there is a drug interaction between these drugs is unclear.

OBJECTIVE

To investigate the risk of clinical outcomes associated with concomitant use of DOACs and amiodarone/diltiazem/verapamil.

METHODS

We identified DOAC users in the Clinical Practice Research Datalink Aurum from 1/1/2011-31/12/2019. We used a cohort design to estimate hazard ratios for Ischaemic stroke, myocardial infarction, venous thromboembolism, intracranial bleeding, gastrointestinal bleeding, other bleeding, cardiovascular mortality, and all-cause mortality comparing DOACs+amiodarone/diltiazem/verapamil users, respectively and DOACs+beta-blocker users. A case-crossover design comparing odds of exposure to different drug initiation patterns for all outcomes in hazard window versus referent window within an individual was also conducted.

RESULTS

Of 397,459 DOAC users, we included 9075 co-prescribed amiodarone, 9612 co-prescribed diltiazem, and 2907 co-prescribed verapamil. There was no difference in risk of any outcomes between DOACs+amiodarone/diltiazem/verapamil users, respectively versus DOACs+beta-blocker users in cohort design. However, in case-crossover design, we observed an odds ratio (OR) of 2.09 (99%CI: 1.37-3.18) for all-cause mortality associated with an initiation of a DOAC while taking amiodarone; which was greater than that observed for DOAC monotherapy (OR: 1.30; 99%CI: 1.25-1.35). Similar findings were observed for cardiovascular mortality and all-cause mortality respectively with diltiazem.

CONCLUSIONS

Our study shows no evidence of higher bleeding or cardiovascular risk associated with co-prescribed DOACs and amiodarone, diltiazem or verapamil respectively. The elevated risks of cardiovascular and all-cause mortality were only observed during DOAC initiation when diltiazem/amiodarone were being taken.

Serious Bleeding in Patients With Atrial Fibrillation Using Diltiazem With Apixaban or Rivaroxaban

Importance

Diltiazem, a commonly prescribed ventricular rate-control medication for patients with atrial fibrillation, inhibits apixaban and rivaroxaban elimination, possibly causing overanticoagulation.

Objective

To compare serious bleeding risk for new users of apixaban or rivaroxaban with atrial fibrillation treated with diltiazem or metoprolol.

Design, Setting, and Participants

This retrospective cohort study included Medicare beneficiaries aged 65 years or older with atrial fibrillation who initiated apixaban or rivaroxaban use and also began treatment with diltiazem or metoprolol between January 1, 2012, and November 29, 2020. Patients were followed up to 365 days through November 30, 2020. Data were analyzed from August 2023 to February 2024.

Exposures

Diltiazem and metoprolol.

Main Outcomes and Measures

The primary outcome was a composite of bleeding-related hospitalization and death with recent evidence of bleeding. Secondary outcomes were ischemic stroke or systemic embolism, major ischemic or hemorrhagic events (ischemic stroke, systemic embolism, intracranial or fatal extracranial bleeding, or death with recent evidence of bleeding), and death without recent evidence of bleeding. Hazard ratios (HRs) and rate differences (RDs) were adjusted for covariate differences with overlap weighting.

Results

The study included 204 155 US Medicare beneficiaries, of whom 53 275 received diltiazem and 150 880 received metoprolol. Study patients (mean [SD] age, 76.9 [7.0] years; 52.7% female) had 90 927 person-years (PY) of follow-up (median, 120 [IQR, 59-281] days). Patients receiving diltiazem treatment had increased risk for the primary outcome (RD, 10.6 [95% CI, 7.0-14.2] per 1000 PY; HR, 1.21 [95% CI, 1.13-1.29]) and its components of bleeding-related hospitalization (RD, 8.2 [95% CI, 5.1-11.4] per 1000 PY; HR, 1.22 [95% CI, 1.13-1.31]) and death with recent evidence of bleeding (RD, 2.4 [95% CI, 0.6-4.2] per 1000 PY; HR, 1.19 [95% CI, 1.05-1.34]) compared with patients receiving metoprolol. Risk for the primary outcome with initial diltiazem doses exceeding 120 mg/d (RD, 15.1 [95% CI, 10.2-20.1] per 1000 PY; HR, 1.29 [95% CI, 1.19-1.39]) was greater than that for lower doses (RD, 6.7 [95% CI, 2.0-11.4] per 1000 PY; HR, 1.13 [95% CI, 1.04-1.24]). For doses exceeding 120 mg/d, the risk of major ischemic or hemorrhagic events was increased (HR, 1.14 [95% CI, 1.02-1.27]). Neither dose group had significant changes in the risk for ischemic stroke or systemic embolism or death without recent evidence of bleeding. When patients receiving high- and low-dose diltiazem treatment were directly compared, the HR for the primary outcome was 1.14 (95% CI, 1.02-1.26).

Conclusions and Relevance

In Medicare patients with atrial fibrillation receiving apixaban or rivaroxaban, diltiazem was associated with greater risk of serious bleeding than metoprolol, particularly for diltiazem doses exceeding 120 mg/d.

Evaluation of Lead-In Direct Oral Anticoagulant Prescribing Practices in Newly Diagnosed Venous Thromboembolism

Various lead-in dosing strategies have been used in clinical practice for venous thromboembolism (VTE), and guidelines do not currently address if the full lead-in dosing duration is necessary after receiving parenteral anticoagulation. This study aims to identify whether full lead-in dosing duration surrounding parenteral anticoagulation affects thrombotic and bleeding outcomes. A single-center, retrospective cohort study was conducted of hospitalized patients diagnosed with VTE and treated with apixaban or rivaroxaban. Patients were grouped depending on duration of lead-in dosing, with the full lead-in dosing group considered as the appropriate duration of the direct oral anticoagulant. The primary outcome was the recurrence of VTE within the index admission to 6 months. Secondary outcomes included major bleeding, clinically relevant minor bleeding, and mortality. Ninety-three patients were prescribed full lead-in dosing, while 99 patients received reduced lead-in dosing. The primary outcome of recurrent VTE was similar between the reduced lead-in group compared to the full lead-in group (3% vs 2%; P = 1.0). Major bleeding within the index admission was significantly higher in the reduced lead-in group: 11 versus 2 (P = .02). There were no significant differences in other secondary outcomes. Full lead-in dosing compared to reduced lead-in dosing duration for VTE had similar rates of thrombotic and mortality events. The higher rate of major bleeding in the reduced lead-in dosing group likely reflects the prescribing practices in less stable patients. This study provides evidence to support reduced lead-in dosing duration in high-risk patients without compromising efficacy outcomes.

Effectiveness and Safety of Different Oral Anticoagulants with P-glycoprotein/ CYP3A4 Inhibitors: A Network Meta-analysis

BACKGROUND

Metabolism of oral anticoagulants (OAC) is affected by P-glycoprotein (P-gp)/ CYP3A4 enzyme. However, the P-gp/CYP3A4 inhibitors are unavoidably used with OACs.

METHODS

Medline, Cochrane, and Embase were systematically searched for randomized controlled trials and cohort studies from inception till 23rd November, 2022 to assess the safety and effectiveness of OACs when concomitantly used with P-gp/CYP3A4 inhibitors. The primary outcomes were major bleeding and gastrointestinal (GI) bleeding. Secondary outcomes were stroke/systemic embolism (SE), all-cause mortality, any bleeding as well as intracranial hemorrhage (ICH). We estimated summary odds ratios (OR) with 95% credible intervals (CI) using pairwise and network meta-analysis with random effects.

RESULTS

A total of 11 studies involving 37,973 patients were included. When concomitantly used with P-pg/ CYP3A4 inhibitors, network meta-analysis indicated that dabigatran, apixaban, and edoxaban were associated with significantly lower risk of major bleeding compared to rivaroxaban, with ORs of 0.56, 0.51 and 0.48, respectively. Rivaroxaban and dabigatran were associated with a significantly increased risk of GI bleeding than warfarin, apixaban and edoxaban. Dabigatran and apixaban were linked with significantly lower risk of any bleeding compared with warfarin (ORs were 0.75 and 0.68, respectively) or rivaroxaban (ORs were 0.67 and 0.60, respectively). Apixaban (OR 0.32) and edoxaban (OR 0.35) were associated with a lower risk of ICH compared with warfarin. There was no difference between any OACs in terms of stroke/SE or all-cause mortality.

CONCLUSION

When concomitantly used with P-gp/CYP3A4 inhibitors, apixaban and edoxaban were associated with a lower risk of bleeding, though no significant difference in effectiveness was observed among all OACs.

Impact of P-glycoprotein and CYP3A4-interacting drugs on clinical outcomes in patients with atrial fibrillation using non-vitamin K antagonist oral anticoagulants: a nationwide cohort study

AIMS

The clinical relevance of common pharmacokinetic interactions with non-vitamin K antagonist oral anticoagulants (NOACs) often remains unclear. Therefore, the impact of P-glycoprotein (P-gp) and CYP3A4 inhibitors and inducers on clinical outcomes in NOAC-treated patients with atrial fibrillation (AF) was investigated.

METHODS AND RESULTS

AF patients were included between 2013 and 2019 using Belgian nationwide data. Concomitant use of P-gp/CYP3A4-interacting drugs at the time of NOAC initiation was identified. Among 193 072 NOAC-treated AF patients, 46 194 (23.9%) and 2903 (1.5%) subjects concomitantly used a P-gp/CYP3A4 inhibitor or inducer, respectively. After multivariable adjustment, concomitant use of P-gp/CYP3A4 inhibitors was associated with significantly higher major bleeding [adjusted hazard ratio (aHR) 1.24, 95% confidence interval (CI) (1.18-1.30)] and all-cause mortality risks [aHR 1.07, 95% CI (1.02-1.11)], but not with thromboembolism in NOAC-treated AF patients. A significantly increased risk of major bleeding was observed with amiodarone [aHR 1.27, 95% CI (1.21-1.34)], diltiazem [aHR 1.28, 95% CI (1.13-1.46)], verapamil [aHR 1.36, 95% CI (1.03-1.80)], ticagrelor [aHR 1.50, 95% CI (1.20-1.87)], and clarithromycin [aHR 1.55, 95% CI (1.14-2.11)]; and in edoxaban [aHR 1.24, 95% CI (1.06-1.45)], rivaroxaban [aHR 1.25, 95% CI (1.16-1.34)], and apixaban users [aHR 1.27, 95% CI (1.16-1.39)], but not in dabigatran users [aHR 1.07, 95% CI (0.94-1.23)]. Concomitant use of P-gp/CYP3A4 inducers (e.g. antiepileptic drugs like levetiracetam) was associated with a significantly higher stroke risk [aHR 1.31, 95% CI (1.03-1.68)], but not with bleeding or all-cause mortality.

CONCLUSION

Concomitant use of P-gp/CYP3A4 inhibitors was associated with higher bleeding and all-cause mortality risks in NOAC users, whereas the use of P-gp/CYP3A4 inducers was associated with higher stroke risks.