Adherence to anticoagulant treatment with dabigatran in a real-world setting

Anticoagulated patient's perception of their illness, their beliefs about the anticoagulant therapy prescribed and the relationship with adherence: impact of novel oral anticoagulant therapy - study protocol for The Switching Study: a prospective cohort study

Background

Anticoagulant therapy is prescribed for millions of patients worldwide for the prevention and treatment of both arterial and venous thrombosis. Historically, only vitamin K antagonists have been available for clinicians to prescribe. The anticoagulation landscape is changing. The recent availability of the novel oral anticoagulants overcome many of the disadvantages associated with vitamin K antagonists. However the lack of formal monitoring and clinic follow-up is a concern for clinicians, as medication adherence is being assumed, which is known to decline in patients prescribed medications for chronic conditions. The switching study is a programme of work investigating the association between medication adherence and patient’s beliefs about anticoagulation therapy (warfarin and subsequently novel oral anticoagulants), together with beliefs about their illness and anticoagulation related quality of life.

Methods/design

The anticoagulation database at King’s College Hospital will be interrogated and two groups of patients will be identified; those with a time in therapeutic range on warfarin of ≥75 % and those <50 %. These groups of patients will have their illness perceptions, anticoagulation specific quality of life and beliefs about medications compared. Those patients in the time in therapeutic range <50 % group, will be then be invited to switch to a novel oral anticoagulant, as per local guidance. Those patients, who do switch, will then be followed longitudinally and have their adherence, illness perceptions, anticoagulation specific quality of life and beliefs about medications, re-evaluated on the novel agent. The results from these sub-studies, will inform a clinical pathway to support patients on these novel agents, which will be evaluated in an independent group of patients.

Discussion

The results from the switching study will be used to develop a clinical pathway to support patient’s prescribed novel oral anticoagulant therapy long-term.

Electronic supplementary material

The online version of this article (doi:10.1186/s12878-016-0061-9) contains supplementary material, which is available to authorized users.

Burden of upper gastrointestinal symptoms in patients prescribed dabigatran for stroke prevention

Background:

Dabigatran, a non-vitamin K antagonist oral anticoagulant, has been shown to prevent stroke in patients with non-valvular atrial fibrillation. Nonetheless, studies show that 10%–30% of those prescribed dabigatran experience dyspepsia that may eventually lead to discontinuation of therapy and loss of clinical benefit.

Aim:

To evaluate the gastrointestinal tolerability of dabigatran utilizing a validated questionnaire, as well as determining subsequent non-compliance and drug discontinuation.

Method:

This is an observational study. All patients were assessed by a validated questionnaire, Hong Kong dyspepsia index, prior to drug prescription and again 4 weeks later.

Results:

In this study, 115 patients with non-valvular atrial fibrillation (mean age: 74.6 ± 11.4 years; mean CHA₂DS₂-VASc score was 3.39 ± 1.59) were prescribed dabigatran. At baseline, the mean Hong Kong dyspepsia index was 12.9 ± 1.6 and nine patients had significant dyspepsia (Hong Kong dyspepsia index ⩾ 16). After 4 weeks, the mean Hong Kong dyspepsia index was similar at 12.6 ± 1.9 (p = 0.23). There was no change in Hong Kong dyspepsia index after initiation of dabigatran in 59 (51.3%) patients, and improvement in 37 (32.2%). Only 19 (16.5%) patients had worsening of Hong Kong dyspepsia index, and among these 19 patients, only 1 patient (0.9%) discontinued dabigatran due to significant dyspepsia.

Conclusion:

Worsening of dyspepsia with dabigatran 110 mg twice daily was uncommon with correct drug administration and clear instructions provided. Systematic assessment of dyspeptic symptoms using a validated questionnaire (i.e. Hong Kong dyspepsia index) before and after treatment initiation allows a more objective comparison of dyspeptic symptoms.

Reducing The Risk Of Stroke In Patients With Nonvalvular Atrial Fibrillation With Direct Oral Anticoagulants. Is One Of These Not Like The Others?

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and increases risk of stroke by nearly 5-fold. While warfarin has been employed successfully to reduce the risk of stroke in these patients, there are a number of challenges with therapy. These include the need for therapeutic monitoring due to variability in patient response, frequent dose adjustments, numerous drug-drug, drug-food, and drug-disease interactions, and a heightened risk of thrombosis and bleeding due to these issues. Current guidelines recommend that the vitamin K antagonists (VKA) or direct oral anticoagulants (DOACs) should be used for thromboprophylaxis in patients with nonvalvular AF at risk for stroke or systemic embolic events. The DOACs include the direct thrombin inhibitor dabigatran and the direct factor Xa inhibitors rivaroxaban, apixaban, and edoxaban. In clinical trials these agents consistently demonstrated a reduction in the risks of hemorrhagic stroke and intracranial hemorrhage compared to VKA. Clinicians now must decide if there are meaningful differences between these agents in order to prescribe the best agent for an individual patient. Therefore, it is critical for clinicians to go beyond information provided in manuscript abstracts, and gain an understanding of the similarities and differences in clinical trial design, patient enrollment, and statistical analysis.

Direct Oral Anticoagulants for the Management of Thromboembolic Disorders

Anticoagulation therapy is central to the management of thromboembolic disorders, and the use of direct oral anticoagulants offers several advantages over standard therapy with parenteral heparins and vitamin K antagonists. In phase III clinical trials, the direct oral anticoagulants (given once or twice daily) all demonstrated favorable benefit–risk profiles compared with conventional standard therapy for the treatment and secondary prevention of venous thromboembolism and for stroke prevention in patients with nonvalvular atrial fibrillation. In clinical practice, many factors may influence overall clinical outcomes in patients receiving anticoagulant therapy, including adherence and persistence to the prescribed therapy, which becomes particularly important during long-term therapy. When choosing an anticoagulant for an individual patient, the pharmacological and clinical profile of the anticoagulant, its dosing regimen, and the patient’s clinical characteristics (eg, renal function and comorbidities) and preferences should be considered. This review examines the rationale for and clinical evidence of the selected dosing regimens of the direct oral anticoagulants for the treatment of venous thromboembolism and stroke prevention in nonvalvular atrial fibrillation. The potential influence of dosing strategies (eg, once- or twice-daily dosing) and other factors on patient adherence and therapy persistence are also discussed.

Effect of Adherence to Oral Anticoagulants on Risk of Stroke and Major Bleeding Among Patients With Atrial Fibrillation

BACKGROUND

In comparison to warfarin, non-vitamin K antagonist oral anticoagulants (NOACs) have the advantages of ease of dosing, fewer drug interactions, and lack of need for ongoing monitoring. We sought to evaluate whether these advantages translate to improved adherence and whether adherence is associated with improved outcomes in patients with atrial fibrillation.

METHODS AND RESULTS

We performed a retrospective cohort analysis by using a large US commercial insurance database to identify 64 661 patients with atrial fibrillation who initiated warfarin, dabigatran, rivaroxaban, or apixaban treatment between November 1, 2010, and December 31, 2014. During a median of 1.1 y of follow-up, 47.5% of NOAC patients had a proportion of days covered of ≥80%, compared with 40.2% in warfarin patients (P<0.001). Patients with CHA2DS2-VASc (risk based on the presence of congestive heart failure, hypertension age 65-74 y, age ≥75 y, diabetes mellitus, prior stroke or transient ischemic attack, vascular disease, sex category) score ≥4 were at increased risk of stroke when they were not taking anticoagulation ≥1 month versus <1 week (1-3 months: hazard ratio [HR] 1.96, 3-6 months: HR 2.64, ≥6 months: HR 3.66; all P<0.001). Patients with CHA2DS2-VASc score 2 or 3 were at increased risk of stroke when they were not taking anticoagulation ≥6 months (HR 2.73, P<0.001). In these patients with CHA2DS2-VASc score ≥2, nonadherence was not associated with intracranial hemorrhage. Among patients with CHA2DS2-VASc score 0 or 1, time not taking anticoagulation was not associated with stroke, but not taking anticoagulation ≥3 months was associated with a significant reduction of bleeding.

CONCLUSIONS

Adherence to anticoagulation is poor in practice and may be modestly improved with NOACs. Adherence to therapy appears to be most important in patients with CHA2DS2-VASc score ≥2, whereas the benefits of anticoagulation may not outweigh the harms in patients with CHA2DS2-VASc score 0 or 1.

Conception of a Personalized Medication Adherence Discharge Kit for Rivaroxaban

Purpose

Due to a lack of necessary monitoring with rivaroxaban, patients have fewer opportunities for education, adherence reinforcement, and follow-up. If rivaroxaban is taken incorrectly, patients are at increased risk for adverse events. The objective was to create personalized rivaroxaban patient adherence kits (R-PAKs) to enhance successful transition from 15 mg twice daily to 20 mg once daily on day 22 of venous thromboembolism (VTE) treatment.

Summary

A review of rivaroxaban drug information and existing medication adherence tools was completed to increase understanding of ways to improve adherence. Clinical pharmacists identified several concerns the R-PAK should address, including patient understanding of correct dose, administration timing, serious adverse effects, and importance of compliance, along with loss to follow-up by a health care provider. In the pilot phase, 100 R-PAKs were created. Each kit includes an educational handout describing adverse effects, administration, and monitoring; a reminder card with dosing information, date to transition, and emergency contact information; and a personalized 28-day pill organizer containing customized dividers to correlate with the first 21 days of treatment. Color-coded stickers denote the first day of starting twice-daily therapy upon discharge and the day of transition to once-daily dosing. The items were distributed in tote bags at discharge along with pharmacist education.

Conclusion

The R-PAKs are being used at a community teaching hospital for patients newly diagnosed with VTE who are discharged on rivaroxaban. The concept of a personalized medication box could be modified for any medication that requires high compliance or dose transitions.

Use of non-vitamin K antagonist oral anticoagulants in atrial fibrillation patients: insights from a specialist atrial fibrillation clinic

BACKGROUND

Non-vitamin K antagonist oral anticoagulants (NOACs) are broadly preferable to vitamin K antagonists (VKAs) for stroke prevention in non-valvular atrial fibrillation (AF) given their overall net clinical benefit. We report an audit of the profile of OAC usage and adverse events in patients attending a specialist AF clinic.

METHODS

Patients attending our specialist AF clinic who were commenced on NOACs for SPAF between January 2013 and August 2014 were included and electronic medical records were retrospectively reviewed between August 2014 and November 2014, to collect demographic, clinical and outcome data. Outcomes included cerebrovascular and bleeding events, death, switching between NOACs or to VKA, dose changes, cessation of NOACs and the reasons for these. To provide perspective, descriptive comparisons were made with a historical cohort of warfarin users attending the specialist AF clinic prior to the introduction of NOACs.

RESULTS

We report data on 813 patients as follows: (i) 233 consecutive patients (mean (standard deviation) age 74 (10) years, 45.1% female) initiated on NOACs, with median (interquartile range) CHA2 DS2 -VASc score 3 (2-5) and HAS-BLED score 1 (1-2); and (ii) a historical cohort of 580 patients on warfarin (mean (SD) age 75 (10) years, 42.1% female) with broadly similar demographics. Overall, 54.5% (127/233) were started on rivaroxaban, 22.7% (53/233) on dabigatran and 22.7% on apixaban. Two patients experienced a transient ischaemic attack; 31 patients (13%) contributed to 37 documented bleeding events of which five bleeds (in four patients, 1.7%) were classified as major. There were seven deaths; cause of death was not available for three and the others were not related to NOACs. Eighteen (7.7%) patients switched NOACs, 2 (0.9%) patients switched to warfarin and 8 (3.4%) had their NOACs stopped. There were no ischaemic strokes in the NOAC cohort, compared with nine in the warfarin cohort, with a similar rate of major bleeding (1.7% for NOACs and 1.6% for warfarin). There were more gastrointestinal haemorrhages in the NOAC cohort (3.4% vs. 0.7% with warfarin).

CONCLUSION

In this specialist AF clinic, patients prescribed NOACs had a favourable adverse event profile with good efficacy for stroke prevention, with a low rate of cessation or switch to warfarin.

Adherence to oral anticoagulants in patients with atrial fibrillation-a population-based retrospective cohort study linking health information systems in the Valencia region, Spain: a study protocol

INTRODUCTION

Adherence to oral anticoagulation (OAC) treatment, vitamin K antagonists or new oral anticoagulants, is an essential element for effectiveness. Information on adherence to OAC in atrial fibrillation (AF) and the impact of adherence on clinical outcomes using real-world data barely exists. We aim to describe the patterns of adherence to OAC over time in patients with AF, estimate the associated factors and their impact on clinical events, and assess the same issues with conventional measures of primary and secondary adherence-proportion of days covered (PDC) and persistence-in routine clinical practice.

METHODS AND ANALYSIS

This is a population-based retrospective cohort study including all patients with AF treated with OAC from 2010 to date in Valencia, Spain; data will be obtained from diverse electronic records of the Valencia Health Agency.

PRIMARY OUTCOME MEASURE

adherence trajectories.

SECONDARY OUTCOMES

(1) primary non-adherence; (2) secondary adherence: (a) PDC, (b) persistence. Clinical outcomes: hospitalisation for haemorrhagic or thromboembolic events and death during follow-up.

ANALYSIS

(1) description of baseline characteristics, adherence patterns (trajectory models or latent class growth analysis models) and conventional adherence measures; (2) logistic or Cox multivariate regression models, to assess the associations between adherence measures and the covariates, and logistic multinomial regression models, to identify characteristics associated with each trajectory; (3) Cox proportional hazard models, to assess the relationship between adherence and clinical outcomes, with propensity score adjustment applied to further control for potential confounders; (4) to estimate the importance of different healthcare levels in the variations of adherence, logistic or Cox multilevel regression models.

ETHICS AND DISSEMINATION

This study has been approved by the corresponding Clinical Research Ethics Committee. We plan to disseminate the project's findings through peer-reviewed publications and presentations at relevant health conferences. Policy reports will also be prepared in order to promote the translation of our findings into policy and clinical practice.

A comparison of the safety and effectiveness of dabigatran and warfarin in non-valvular atrial fibrillation patients in a large healthcare system

Dabigatran is approved for stroke risk reduction in patients with nonvalvular atrial fibrillation (NVAF). Data from diverse clinical practice settings will help establish whether the risk:benefit ratio seen in clinical trials is comparable with routine clinical care. This study aimed to compare the safety and effectiveness of dabigatran and warfarin in clinical practice. We undertook a propensity score-matched (PSM) cohort study (N=12,793 per group; mean age 74) comparing treatment with dabigatran or warfarin in the US Department of Defense claims database, October 2009 to July 2013. Treatment-naïve patients with first prescription claim for dabigatran (either FDA-approved dose) or warfarin between October 2010 and July 2012 (index) and a diagnosis of NVAF during the 12 months before index date were included. Primary outcomes were stroke and major bleeding. Secondary outcomes included ischaemic and haemorrhagic stroke, major gastrointestinal (GI), urogenital or other bleeding, myocardial infarction (MI) and death. Time-to-event was investigated using Kaplan-Meier survival analyses. Outcomes comparisons were made utilising Cox-proportional hazards models of PSM groups. Dabigatran users experienced fewer strokes (adjusted hazard ratio [95 % confidence intervals] 0.73 [0.55-0.97]), major intracranial (0.49 [0.30-0.79]), urogenital (0.36 [0.18-0.74]) and other (0.38 [0.22-0.66]) bleeding, MI (0.65 [0.45-0.95]) and deaths (0.64 [0.55-0.74]) than the warfarin group. Major bleeding (0.87 [0.74-1.03]) and major GI bleeding (1.13 [0.94-1.37]) was similar between groups and major lower GI bleeding events were more frequent (1.30 [1.04-1.62]) with dabigatran. In conclusion, compared with warfarin, dabigatran treatment was associated with a lower risk of stroke and most outcomes measured, but increased incidence of major lower GI bleeding.

Dabigatran-Associated Intracranial Hemorrhage: Literature Review and Institutional Experience

Dabigatran etexilate is an oral direct thrombin inhibitor approved for prevention of stroke and systemic embolization in patients with nonvalvular atrial fibrillation and for the treatment of venous thromboembolism. Although dabigatran has a favorable safety profile, predictable pharmacokinetics, fewer drug interactions than warfarin, and does not require monitoring, clinical data regarding dabigatran reversal are limited. In addition, currently available laboratory assays allow measurement of the presence, but not extent, of dabigatran-associated anticoagulation. Patient age, renal function, weight, concurrent drug therapy, adherence, and concomitant disease states can affect dabigatran's efficacy and safety. Management of dabigatran-related intracranial hemorrhage must be approached on a case-by-case basis and include assessment of degree of anticoagulation, severity of hemorrhage, renal function, timing of last dabigatran dose, and risk of thromboembolic events. Initial management includes dabigatran discontinuation and general supportive measures. Oral activated charcoal should be administered in those who ingested dabigatran within 2 hours. Four-factor prothrombin complex concentrates (4PCCs), activated PCC, or recombinant activated factor VII use may be reasonable but is not evidence based. Reserve fresh frozen plasma for patients with dilutional coagulopathy. If readily available, hemodialysis should be considered, particularly in patients with advanced kidney injury or excessive risk of thromboembolic events. More clinical studies are needed to determine a standardized approach to treating dabigatran-associated intracranial hemorrhage. Institutional protocol development will facilitate safe, efficacious, and timely use of the limited management options.

Direct Oral Anticoagulants for the Prevention of Stroke in Patients with Nonvalvular Atrial Fibrillation: Understanding Differences and Similarities

The presence of atrial fibrillation (AF), the most common sustained cardiac arrhythmia, significantly increases the risk for stroke. Current guidelines recommend that the vitamin K antagonist warfarin or direct oral anticoagulants (DOACs), such as the approved direct thrombin inhibitor dabigatran and the approved direct factor Xa inhibitors apixaban, rivaroxaban, and edoxaban, should be used for thromboprophylaxis in patients with nonvalvular AF at risk for stroke or systemic embolic events (SEE). Warfarin, the mainstay of stroke prevention in AF, increases the risk of major bleeding. Furthermore, warfarin therapy comes with several limitations including frequent monitoring and the need for dose adjustments, unpredictable pharmacokinetics and pharmacodynamics, and the potential for significant drug-drug and food-drug interactions. The DOACs were developed to overcome these limitations while maintaining or surpassing warfarin's efficacy and safety profiles. All four DOACs have similar or better efficacy and safety compared with warfarin and are therefore valuable alternatives for the prevention of stroke and SEE in patients with nonvalvular AF. Understanding the subtle differences in the DOACs' pharmacology, phase 3 study designs, and trial outcomes will allow for a more tailored approach in selecting the right oral anticoagulant for each patient.

Direct oral anticoagulants in atrial fibrillation: can data from randomized clinical trials be safely transferred to the general population? Yes

Atrial fibrillation is the most common arrhythmia and is associated with significant morbidity and mortality. The current therapeutic options for patients at high thromboembolic risk include the vitamin K antagonists and the direct oral anticoagulants. These novel agents have been evaluated in more than 40,000 patients enrolled in four large randomized controlled trials for stroke prevention in non-valvular atrial fibrillation. When these results were pooled together, a greater efficacy profile, as well as a consistent reduction in life-threatening bleeding was shown in comparison to vitamin K antagonists. Randomized controlled trials offer the highest level of evidence on the efficacy and safety of an intervention; however, their results may not be directly applicable to the general population. The results of a number of post-marketing observational studies from the United States and Europe have been published. The results of these studies substantially confirm the findings of the randomized trials and show a favorable safety profile with the use of the direct oral anticoagulants even in unselected populations.

A Comparison of Dabigatran With Warfarin for Stroke Prevention in Atrial Fibrillation in an Asian Population

BACKGROUND

The Asian population with atrial fibrillation (AF) have a higher risk of stroke than the caucasian population and a higher risk of intracranial bleeding when anticoagulated with warfarin. There are few real-world studies comparing the efficacy of non-vitamin K antagonist oral anticoagulants (NOACs) and warfarin among Asian patients to assess its outcomes of ischemic stroke and hemorrhagic stroke.

METHODS

A retrospective cohort study of 1000 patients on dabigatran and warfarin from 2009 to 2013.

RESULTS

Data were available for 500 patients on dabigatran and 500 patients on warfarin. The average follow-up duration was 315 ± 280 days in the dabigatran group and 355 ± 232 in the warfarin group. The time in therapeutic range (TTR) was 53.2% in the warfarin-treated group, with 32.8% of patients in the subtherapeutic international normalized ratio range of <2. None of the patients in the dabigatran group had ischemic cerebrovascular accident (CVA) compared to 4 (0.8%) patients in the warfarin group, hazard ratio (HR) 0.13, P = .3. There was 1 (0.2%) patient in both dabigatran and warfarin groups with hemorrhagic CVA (HR 1.16, P = .92). There were 3 (0.6%) patients with major bleeding in the dabigatran group compared to 2 (0.4%) patients in the warfarin group (HR 1.57, P = .59).

CONCLUSION

There were similar rates of efficacy for outcomes of ischemic CVA, hemorrhagic CVA, and bleeding when comparing dabigatran with warfarin. Our study shows that despite similar efficacy, suboptimal TTR rates and inconveniences with warfarin demonstrate that NOACs are preferred for stroke prevention in AF.

Dabigatran adherence in atrial fibrillation patients during the first year after diagnosis: a nationwide cohort study

BACKGROUND

There is a perception among physicians that lack of routine monitoring with non-vitamin K antagonist oral anticoagulants (NOACs) may lead to poor adherence to medication. We studied adherence during the first year of usage in a cohort of patients with newly diagnosed non-valvular atrial fibrillation (AF) started on the NOAC, dabigatran etexilate.

METHODS AND RESULTS

Nationwide Danish patient and prescription purchase registries were used to identify newly diagnosed AF patients taking dabigatran, comorbidities, and refill patterns under a twice-daily, one pill regimen. Adherence was characterized among remaining users (N = 2960) after 1 year using the proportion of days covered (PDC), gap rates and restart rates. The overall 1-year PDC was 83.9%, with 76.8% of patients having a 1-year PDC in excess of 80%. Patients with a CHA2 DS2 -VASc score ≥ 2 were more adherent to medication regimes than patients with a CHA2 DS2 -VASc score of 1 (PDC ratio, 1.12; 95% confidence interval [CI], 1.08-1.17) and generally patients with higher morbidity showed more adherence. Patients with prior bleeding were not less adherent to medication regimes than patients with no prior bleeding (PDC ratio, 1.02; 95% CI, 0.98-1.06). The overall gap rate was 1.4 gaps per year. There were no clear tendencies in gap rates among subgroups, although patients with higher morbidity tended to have slightly more, but shorter, gap periods.

CONCLUSIONS

More than 75% of patients were showed > 80% adherence to medication regimes during the first year. Patients with higher morbidity, including patients with a higher risk of stroke or bleeding, exhibited better adherence. This improvement may be attributable to more regular contact with the healthcare system.

Warfarin versus dabigatran etexilate: an assessment of efficacy and safety in patients with atrial fibrillation

INTRODUCTION

Oral anticoagulation is the mainstay for stroke and thromboembolic event prevention in patients with atrial fibrillation (AF). Given limitations of warfarin therapy, non-vitamin K oral anticoagulants have been developed including direct thrombin inhibitors (i.e., dabigatran etexilate). Dabigatran etexilate has been tested thoroughly in terms of efficacy and safety in clinical trials and studies, involving 'real-world' cohorts. In this review, currently available evidence in patients with non-valvular AF is discussed.

AREAS COVERED

The pharmacology, efficacy and safety, and current aspects of use of dabigatran etexilate in patients with non-valvular AF are reviewed in a comparative manner to warfarin both for chronic anticoagulation and in different clinical settings.

EXPERT OPINION

Dabigatran etexilate appeared to have several pharmacokinetic and pharmacodynamic advantages over warfarin, as well as a favorable efficacy and safety profile being at least noninferior and often superior to warfarin in patients with non-valvular AF. The latter was shown in the clinical trials, meta-analyses and studies with 'real-world' data. Currently ongoing trials will expand the body of evidence on warfarin and will aid decision making in currently controversial areas. Important limitations of dabigatran etexilate include contraindications for its use in patients with prosthetic heart valves and end-stage chronic kidney disease.

A clinician's perspective: novel oral anticoagulants to reduce the risk of stroke in nonvalvular atrial fibrillation--full speed ahead or proceed with caution?

Over the past few years, three novel oral anticoagulants, dabigatran, rivaroxaban, and apixaban, have been approved in the USA and Europe to reduce the risk of stroke or systemic embolism in patients with nonvalvular atrial fibrillation, and the results of a Phase III trial for a fourth novel oral anticoagulant, edoxaban, have recently been published. The aim of this review is to examine this indication from a clinician's perspective, highlighting efficacy and safety results from the major trials with these novel oral agents. Clinical issues regarding bleeding, monitoring, and reversal are discussed, along with requirements to consider when interrupting treatment with a novel oral anticoagulant for the purpose of transitioning to another anticoagulant and prior to cardioversion, ablation, percutaneous coronary intervention, or emergency surgery. The cost-effectiveness of each of the approved novel oral anticoagulants is reviewed, and the author provides recommendations for selecting appropriate patients for these agents.

Dabigatran Versus Warfarin in Atrial Fibrillation

Safety issues have been raised about dabigatran. We aimed to investigate the occurrence of safety outcomes in patients who had atrial fibrillation and a risk of stroke. We analyzed 439 patients prescribed dabigatran (n = 220) or warfarin (n = 219). Ischemic stroke occurred in 15 (6.8%) patients in the warfarin group versus 5 (5.2%) patients in the 110-mg group versus 1 (0.8%) patient in the 150-mg dabigatran group ( P = .015). Intracranial hemorrhage occurred in 6 (2.7%) patients in the warfarin group versus 3 (2.4%) patients in the 150-mg dabigatran group ( P = .104). Death from any cause occurred in 10 (4.6%) patients in the warfarin group versus 1 (1.0%) patient in the 110-mg dabigatran group ( P = .005). Dabigatran was associated with less ischemic stroke and death from any cause than warfarin. Dabigatran may be a better option for stroke prophylaxis, where recommended monitoring with warfarin is suboptimal.

Appropriateness of Prescribing Dabigatran Etexilate and Rivaroxaban in Patients With Nonvalvular Atrial Fibrillation

Background: Direct oral anticoagulants have been developed to address some of the drawbacks of vitamin-K antagonists. However, special attention should be given when using these drugs, especially in patients with renal insufficiency, questionable compliance, and those at high risk of bleeding. Objective: To evaluate the appropriateness of prescribing dabigatran etexilate (DE) and rivaroxaban in patients with nonvalvular atrial fibrillation (NVAF) in real-life clinical practice. Methods: This was a prospective study that included patients presenting to a teaching hospital from April to mid-October 2013, who were taking rivaroxaban or DE for NVAF. Appropriateness of prescribing was evaluated using 9 of the 10 criteria of the Medication Appropriateness Index. The primary outcome measure was the prevalence of inappropriate prescribing. Secondary outcome measures included ( a) categories of inappropriateness, ( b) prevalence of adverse drug events, and ( c) interventions made by a clinical pharmacist to optimize prescribing. Results: A total of 69 patients were evaluated; 16 patients (23%) had 1 inappropriate criterion, and an additional 18 (26%) had more than 1 inappropriate criterion. The most frequent inappropriate criteria were inappropriate choice (28% of patients), wrong dosage (26%), and impractical modalities of administration (26%). An adverse event (AE) was found in 51% of patients (including 8 patients with transient ischemic attack/stroke). The clinical pharmacists performed 48 interventions, and 94% were accepted by the physician. Conclusions: Inappropriate use of DE and rivaroxaban in patients with NVAF is frequent and possibly leads to AEs. Reinforcing education of health care professionals and patients is needed. Collaboration with clinical pharmacists can contribute to better use.

The newer direct oral anticoagulants: a practical guide

Anticoagulation therapy is one of the most important advances in modern medicine, saving thousands of lives from the complications of atrial fibrillation and mechanical heart valves and preventing recurrent venous thromboembolism. Warfarin and heparins have been the predominant anticoagulants used until the past decade. However, the arrival of newer target-specific anticoagulants has brought us easier and equally effective agents, although no specific antidotes are yet available. Being relatively newer drugs, physicians need to be familiar with the various practical issues that may be encountered with the prescription of these drugs, which are summarised in this review.

Advantages and limitations of the new anticoagulants

During recent years, three new anticoagulants (dabigatran, rivaroxaban and apixaban) have been introduced to the market, probably with one more anticoagulant (edoxaban) in the next 2 years. This review is not intended to compare the efficacy and risks of these new agents, but rather to detail the advantages and limitations. The pharmacokinetic characteristics of these drugs have few drug and food interactions, predictable dose responses, and rapid onset and offset, thus resulting in simplified management of the patient requiring anticoagulant therapy. No routine laboratory monitoring is required. A somewhat unexpected, but exciting observation involving the new anticoagulants, is the uniform reduction in intracranial bleeding by one-half compared with warfarin. The potential limitations of the new anticoagulants include uncertainty regarding assessment of drug levels, safe drug levels for major surgery, management of major bleeding, renal dependence, multiple dose regimens, adherence in the absence of frequent monitoring and unknown, rare side effects that were not captured in the trials. This review should clarify some of these concerns.