Continuation of dabigatran therapy in "real-world" practice in Hong Kong

Stroke Prevention in Atrial Fibrillation: A Scientific Statement of JACC: Asia (Part 2)

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is associated with substantial increases in the risk for stroke and systemic thromboembolism. With the successful introduction of the first non-vitamin K antagonistdirect oral anticoagulant agent (NOAC) in 2009, the role of vitamin K antagonists has been replaced in most clinical settings except in a few conditions for which NOACs are contraindicated. Data for the use of NOACs in different clinical scenarios have been accumulating in the past decade, and a more sophisticated strategy for patients with AF is now warranted. JACC: Asia recently appointed a working group to summarize the most updated information regarding stroke prevention in AF. The aim of this statement is to provide possible treatment options in daily practice. Local availability, cost, and patient comorbidities should also be considered. Final decisions may still need to be individualized and based on clinicians' discretion. This is part 2 of the statement.

Diastolic blood pressure achieved at target systolic blood pressure (120-140 mm Hg) and dabigatran-related bleeding in patients with nonvalvular atrial fibrillation: A real-world study

Objective:

Elevated systolic blood pressure (SBP) can significantly increase the bleeding risk in patients with atrial fibrillation (AF). However, it is unclear whether elevated diastolic blood pressure (DBP), in the presence of well-controlled SBP is also associated with bleeding. Therefore, we aimed to examine the specific relationship between DBP and bleeding in patients with AF treated with anticoagulants and had well-controlled SBP.

Methods:

We analyzed data from 542 of 929 patients with nonvalvular AF (NVAF) treated with dabigatran from the Monitor System for the Safety of Dabigatran Treatment study (MISSION-AF) who had a SBP of 120–140 mm Hg at the time of enrollment. The association between DBP and bleeding was analyzed using multivariate logistic regression and smooth curve fitting (penalized spline method). Threshold saturation effect analysis was used to show the nonlinear relationship between DBP and bleeding.

Results:

After 3 months of follow-up, 49 bleeding events occurred. Compared with participants with DBP <80 mm Hg, those with DBP ≥80 mm Hg had a 118% higher bleeding risk [hazard ratio (HR): 2.18; 95% confidence interval (CI): 1.19, 3.98; p<0.05]. The smooth curve showed a nonlinear relationship between DBP and bleeding risk, and the inflection point of DBP was 80 mm Hg. When DBP was ≥80 mm Hg, the bleeding risk increased by 59% (HR: 1.59; 95% CI: 1.16, 2.19; p<0.05) for every 5 mm Hg increase in DBP.

Conclusion:

Upon achieving an optimal SBP (120–140 mm Hg), a higher DBP might be associated with a higher bleeding risk in patients with NVAF treated with dabigatran.

Reasons for discontinuing oral anticoagulation therapy for atrial fibrillation: a systematic review

Introduction

Atrial fibrillation (AF) is the most common cardiac arrhythmia and can lead to significant comorbidities and mortality. Persistence with oral anticoagulation (OAC) is crucial to prevent stroke but rates of discontinuation are high. This systematic review explored underlying reasons for OAC discontinuation.

Methods

A systematic review was undertaken to identify studies that reported factors influencing discontinuation of OAC in AF, in 11 databases, grey literature and backwards citations from eligible studies published between 2000 and 2019. Two reviewers independently screened titles, abstracts and papers against inclusion criteria and extracted data. Study quality was appraised using Gough’s weight of evidence framework. Data were synthesised narratively.

Results

Of 6,619 sources identified, 10 full studies and 2 abstracts met the inclusion criteria. Overall, these provided moderate appropriateness to answer the review question. Four reported clinical registry data, six were retrospective reviews of patients’ medical records and two studies reported interviews and surveys. Nine studies evaluated outcomes relating to dabigatran and/or warfarin and three included rivaroxaban (n = 3), apixaban (n = 3) and edoxaban (n = 1). Bleeding complications and gastrointestinal events were the most common factors associated with discontinuation, followed by frailty and risk of falling. Patients’ perspectives were seldom specifically assessed. Influence of family carers in decisions regarding OAC discontinuation was not examined.

Conclusion

The available evidence is derived from heterogeneous studies with few relevant data for the newer direct oral anticoagulants. Reasons underpinning decision-making to discontinue OAC from the perspective of patients, family carers and clinicians is poorly understood.

Adverse drug reactions with oral anticoagulants: data from sicilian spontaneous reporting system database

OBJECTIVE

Direct oral anticoagulants (DOACs) were developed to avoid the limitations of vitamin K antagonists (VKAs). DOACs are associated with a greater incidence of gastrointestinal bleeding and a smaller number of intracranial haemorrhages than VKAs. Therefore, it is important to deepen our knowledge of their safety profiles. The aim of this study was thus to analyse adverse drug reaction (ADR) reports on DOACs and VKAs using the Sicilian Spontaneous Reporting System (SRS) database.

METHODS

All ADR reports with DOACs and VKAs as suspected drugs that were entered into the Sicilian SRS database during the period 2001-2019 were selected. In detail, all reports with the following single active substances were included: dabigatran etexilate, rivaroxaban, apixaban and edoxaban; acenocoumarol and warfarin were included as a comparator group. Descriptive statistical methodology was used to evaluate characteristics of the reported cases with a case-by-case assessment.

RESULTS AND DISCUSSION

Out of 521 reports related to anticoagulants, 444 (85.2%) and 77 (14.8%) involved DOACs and VKAs, respectively. DOAC-related reports were mainly of gastrointestinal disorders. In contrast, VKAs were mostly associated with blood and lymphatic system disorders, injury, investigations and vascular disorders. Many more cases of ADRs in the form of gastrointestinal disorders concerned dabigatran etexilate (n = 179, 73.7%) than the other DOACs, while ADRs in the form of blood disorders were mainly associated with acenocoumarol (n = 27, 57.4%). The most commonly reported Preferred Terms for DOACs were dyspepsia (n = 89, 17.1%), upper abdominal pain (n = 41, 9.2%) and pruritus (n = 26, 5.8%), whereas for VKAs, they were anaemia (n = 21, 27.3%) and hypocoagulable state (n = 18, 3.5%). Potentially interacting concomitant medications particularly included antithrombotic agents (n = 19, 4.3%) for DOACs and proton-pump inhibitors (PPIs) (n = 37, 48.1%) and antithrombotic agents (n = 13, 16.9%) for VKAs.

CONCLUSION

The ADRs most commonly associated with DOACs, especially dabigatran, were gastrointestinal disorders, particularly gastrointestinal bleeding. Our study also highlights the potential role of drug-drug interactions in the ADRs. The cases of gastrointestinal bleeding highlight the need for careful prescribing of DOACs and use of potentially interacting concomitant drugs.

Updating the Cost Effectiveness of Oral Anticoagulants for Patients with Atrial Fibrillation Based on Varying Stroke and Bleed Risk Profiles

BACKGROUND

Previous investigations into the cost effectiveness of direct oral anticoagulants only considered individual stroke risk but not bleed risk even though bleeding is an important and potentially fatal side effect for anticoagulated patients.

OBJECTIVE

This study aimed to evaluate the cost effectiveness of dabigatran, rivaroxaban, apixaban, and edoxaban vs warfarin in patients with atrial fibrillation with varying stroke/bleed risk profiles over a lifetime horizon.

METHODS

A Markov micro-simulation was adapted to examine the lifetime costs and quality-adjusted survival of five anticoagulants from a US private payer's perspective. The study hypothetical cohort consisted of 10,000 patients with atrial fibrillation with age, CHA₂DS₂-VASc, and HAS-BLED scores similar to a commercially insured patient with atrial fibrillation cohort. Model input parameters including the efficacy and safety of each strategy, utilities, and cost were estimated from public sources, published literature, and analysis conducted in the IBM MarketScan database. Lifetime cost, quality-adjusted life-years, and incremental cost-effectiveness ratios were assessed for each treatment strategy. Subgroup analyses stratified by age, stroke risk score alone, bleed risk score alone and both were performed. Uncertainty was assessed by a deterministic sensitivity analysis and a probabilistic sensitivity analysis.

RESULTS

The base-case analysis suggested dabigatran was the optimal treatment with an incremental cost-effectiveness ratio of $35,055 per quality-adjusted life-year relative to warfarin. Subgroup analyses stratified by age, stroke risk score, and bleed risk score alone were largely consistent with the base-case analysis. Subgroup analyses stratified by both stroke and bleed risk score showed edoxaban was the preferred treatment in patients with a low stroke and a low or medium bleed risk, and patients with a high stroke and low bleed risk. Apixaban was the preferred treatment in patients with a medium stroke and high bleed risk. Results of the deterministic sensitivity analysis indicate the model results were most sensitive to the drug cost and hazard ratio for stroke and bleeding event. Results of the probability sensitivity analysis showed dabigatran is cost effective vs. other treatments in 32.8% and 42.4% of iterations at a willingness to pay of $50,000/quality-adjusted life-year and a willingness to pay of $100,000/quality-adjusted life year, respectively.

CONCLUSIONS

From a US private payer's perspective, dabigatran appears cost effective compared with other anticoagulants. This study indicated risk stratification especially considering both stroke and bleed risk simultaneously is important not only in clinical practice but also in health technology assessment exercises among patients with atrial fibrillation.

A comprehensive appraisal of dabigatran etexilate clinical evidence and applications: a 10-year-long story

During the last decade, non-vitamin K antagonist oral anticoagulants (NOACs) revolutionized the thromboprophylaxis management of several medical conditions, including atrial fibrillation and venous thromboembolism. Dabigatran etexilate was the first NOAC widely available worldwide, and it is currently the only one that directly inhibits thrombin. More recently, the availability of idarucizumab, a specific reversal agent, has increased the safety of dabigatran use in clinical practice, especially for those patients with severe and life-threatening bleeding. This review aims to summarize current evidence on dabigatran, starting from its pharmacological characteristics, and providing an updated overview of pivotal randomized controlled trials and real-world data on its efficacy and safety.

Adherence to dabigatran and the influence of dabigatran-induced gastrointestinal discomfort in the real-world practice

BACKGROUND

Dabigatran-induced gastrointestinal discomfort (DGID) is an important factor influencing the adherence to dabigatran. We investigated the incidence and risk factors of DGID and its impact on the adherence and persistence to dabigatran.

METHODS

We prospectively enrolled the patients prescribed with dabigatran in 10 tertiary hospitals of the South Korea. The adherence was assessed using the percentage of the prescribed doses of the medication presumably taken by the patient (PDT by pill count). We evaluated the relationship between DGID and the baseline GI symptoms or the previous GI disease history using a questionnaire.

RESULTS

A total of 474 patients (mean age 67.8 ± 9.3 years, male 68.6%, and mean CHA₂DS₂-VASc score 2.2 ± 1.2) were enrolled. The adherence assessed by the PDT was 93.5 ± 5.5% at 1-month and 96.4 ± 8.4% at 6-months among the persistent patients. During the 6-month follow-up, 82 (18.1%) patients discontinued dabigatran, and the most common reason for dabigatran discontinuation was DGID (49, 59.8%). Sixty-eight (14.3%) patients experienced DGID, and there was no difference in the clinical factors between those with or without DGID. Among the patients who experienced DGID, 42 discontinued dabigatran (61.8%). In a multivariate analysis, DGID was the only predictor of dabigatran discontinuation and a low adherence.

CONCLUSION

Overall adherence of dabigatran was excellent, but those with DGID showed low adherence and persistence. Furthermore, it was challenging to predict DGID by clinical parameters. Therefore, it is recommended to follow the patients closely to check for DGID when prescribing dabigatran.

Peripheral leukocyte count and risk of bleeding in patients with non-valvular atrial fibrillation taking dabigatran: a real-world study

BACKGROUND

The association between peripheral leukocyte count and bleeding events in nonvalvular atrial fibrillation (NVAF) patients treated with dabigatran remains unclear. This study aimed to explore the association between leukocyte count and bleeding events after excluding other confounders in NVAF patients taking dabigatran.

METHODS

A total of 851 NVAF patients treated with dabigatran (110 mg bid) were recruited from 12 centers in China from February 2015 to December 2017. Follow-up was completed by May 2018. The exposure and outcome variables were leukocyte count measured at baseline and the number of bleeding events within the subsequent 6 months. Multivariate Cox proportional hazards models were constructed to analyze independent associations, and a Cox proportional hazards regression with cubic spline functions and smooth curve fitting (penalized spline method) was used to address nonlinearity between leukocyte count and bleeding. The inflection point was calculated using a recursive algorithm, and then a two-piecewise Cox proportional hazards model for both sides of the inflection point was constructed.

RESULTS

During 6-month follow-up, 87 participants occurred bleeding events. For every 1 × 10/L increase in leukocyte count, the risk of bleeding increased by 11% (hazard ratio [HR]: 1.11, 95% confidence interval [CI]: 0.99-1.25). The smooth curve showed nonlinear relationship between leukocyte count and bleeding events. The inflection point of the leukocyte count was 6.75 × 10/L. For leukocyte counts < 6.75 × 10/L, the HR (95% CI) was 0.88 (0.69-1.13), and for leukocyte counts ≥ 6.75 × 10/L, the HR (95% CI) was 1.28 (1.09-1.51).

CONCLUSION

This study found a J-shaped association between baseline leukocyte count and risk of bleeding in NVAF patients treated with dabigatran.

CLINICAL TRIAL REGISTRATION

NCT02414035, https://clinicaltrials.gov.

Real-World Adherence and Persistence to Direct Oral Anticoagulants in Patients With Atrial Fibrillation: A Systematic Review and Meta-Analysis

BACKGROUND

Stroke reduction with direct oral anticoagulants (DOACs) in atrial fibrillation (AF) is dependent on adherence and persistence in the real-world setting. Individual study estimates of DOAC adherence/persistence rates have been discordant. Our aims were to characterize real-world observational evidence for DOAC adherence/persistence and evaluate associated clinical outcomes in patients with AF.

METHODS AND RESULTS

PubMed, EMBASE, and CINAHL were searched from inception to June 2018. Observational studies that reported real-world DOAC adherence/persistence in patients with AF were included. Study quality was assessed using the Newcastle-Ottawa Scale. Meta-analyses for pooled estimates were performed using DerSimonian and Laird random-effects models. Outcomes included DOAC mean proportion of days covered or medication possession ratio, proportion of good adherence (proportion of days covered/medication possession ratio ≥80%), persistence, DOAC versus vitamin K antagonists persistence, and clinical outcomes associated with nonadherence/nonpersistence. Forty-eight observational studies with 594 784 unique patients with AF (59% male; mean age 71 years) were included. The overall pooled mean proportion of days covered/medication possession ratio was 77% (95% CI, 75%-80%), proportion of patients with good adherence was 66% (95% CI, 63%-70%), and proportion persistent was 69% (95% CI, 65%-72%). The pooled proportion of patients with good adherence was 71% (95% CI, 64%-78%) for apixaban, 60% (95% CI, 52%-68%) for dabigatran, and 70% (95% CI, 64%-75%) for rivaroxaban. Similar patterns were found for pooled persistence by agent. The pooled persistence was higher with DOACs than vitamin K antagonists (odds ratio, 1.44 [95% CI, 1.12-.86]). DOAC nonadherence was associated with an increased risk of stroke (hazard ratio, 1.39 [95% CI, 1.06-1.81]).

CONCLUSIONS

Suboptimal adherence and persistence to DOACs was common in patients with AF, with 1 in 3 patients adhering to their DOAC <80% of the time, which was associated with poor clinical outcomes in nonadherent patients. Although it is convenient that DOACs do not require laboratory monitoring, greater effort in monitoring for and interventions to prevent nonadherence may be necessary to optimize stroke prevention. Increased clinician awareness of DOAC nonadherence may help identify at-risk patients.

Real-world 2-year outcome of atrial fibrillation treatment with dabigatran, apixaban, and rivaroxaban in patients with and without chronic kidney disease

Patients with non-valvular atrial fibrillation (NVAF) and chronic kidney disease (CKD) are at increased risk of stroke and bleeding. Although direct oral anticoagulant (DOAC) trials excluded patients with severe CKD, a growing portion of CKD patients have been starting DOACs and limited data from real-world outcome in this high-risk setting are available. The INSigHT registry included 632 consecutive NVAF patients that started apixaban (256 patients, 41%), dabigatran (245, 39%) and rivaroxaban (131, 20%) between 2012 and 2015. Based on creatinine clearance, two sub-cohorts were defined: (1) non-CKD group (CrCl 60-89 mL/min, 413 patients) and (2) CKD group (15-59 ml/min, 219). Compared to non-CKD patients, those with CKD, were at higher ischemic (CHA₂DS₂-VASc 4.5 vs 2.9, p < 0.001) and hemorrhagic risk (HAS-BLED 2.4 vs 1.8, p < 0.001). At 2-year follow-up, the overall ISTH-major bleeding and thromboembolic event rates were 5.2% and 2.3% and no significant difference between non-CKD and CKD patients for both efficacy and safety endpoints were observed. In non-CKD patients, the 2-year ISTH-major bleeding rates were higher in rivaroxaban group (HR 2.9, 95% CI 1.1-7.3; p = 0.047) while dabigatran showed non-significant excess in thromboembolic events (HR 4.3, 95% CI 0.9-20.8; p = 0.068). In CKD patients, a significantly higher rate of thromboembolic events was observed in rivaroxaban (HR 6.3, 95% CI 1.1-38.1; p = 0.044). This real-world, non-insurance database registry shows remarkable 2-year safety and efficacy profile of DOACs even in patients with moderate to severe CKD. Head to head differences between DOACs are exploratory, hypothesis generating and warrant further investigation in larger studies.

Long-term outcome in patients with non-valvular atrial fibrillation on dabigatran: a prospective cohort study

INTRODUCTION

Most studies on thromboembolic and bleeding risk in patients with non-valvular atrial fibrillation (NVAF) exposed to non-vitamin K oral anticoagulants stem from interrogation of insurance databases. Areas covered: We studied 742 consecutive patients with NVAF who started treatment with dabigatran in three hospitals in Italy. Average follow-up was 1.80 years. Mean age was 76.2 years. CHA₂DS₂VASc score was 0-1 in 37 (5%), 2 in 97 (13%) and ≥ 3 in 604 (82%) patients. NVAF was permanent in 349 (48%). Overall, 76% of patients remained on treatment over the entire follow-up period. Among 180 patients who discontinued permanently, the most frequent reasons were dyspepsia (33.9%), bleeding (17.8%), and renal worsening (12.1%). About 48% and 74% of permanent discontinuations occurred during the first 6 and 12 months of treatment, respectively. Rates of major events (per 100 patient-years) were 0.75 for stroke, 0.31 for myocardial infarction, 1.50 for all-cause death, and 1.80 for major bleedings. The rate of intracranial bleedings was 0.45 and that of major gastrointestinal bleedings was 0.75. Expert opinion: This prospective cohort study confirms the low incidence of stroke, major bleeding and intracranial bleeding, and a 76% persistence with treatment, in patients with NVAF treated with dabigatran over about 2 years.

Impact of provision of time in therapeutic range value on anticoagulation management in atrial fibrillation patients on warfarin

INTRODUCTION

The importance of time in therapeutic range (TTR) in patients prescribed warfarin therapy for stroke prevention in atrial fibrillation (AF) cannot be overemphasised.

AIM

To evaluate the impact of provision of TTR results during clinic visits on anticoagulation management.

DESIGN

Single-centred, randomised controlled study.

SETTING

Fifteen arrhythmia clinics in Hong Kong.

PATIENTS

AF patients prescribed warfarin.

INTERVENTIONS

Provision of TTR or no provision of TTR.

MAIN OUTCOME MEASURES

A documented discussion between doctors and patients about switching warfarin to a non-vitamin K oral anticoagulant (NOAC).

RESULTS

Four hundred and eighty one patients with AF prescribed warfarin were randomly assigned to (1) a TTR provision group or (2) control. Their mean age was 73.6±12.0 years and 60.7% were men. The mean CHA₂DS₂-VASc score was 3.2±1.6 and the mean HASBLED score was 1.7±1.2. The mean TTR was 63.9%±29.9%. At the index clinic visit, 71 of 481 patients (14.8%) had a documented discussion about switching warfarin to a NOAC. Patients with provision of TTR results were more likely to discuss switching warfarin to a NOAC than controls (19.1% vs 10.6%, P=0.03), especially those with a TTR <65% (35.2% vs 10.6%, P<0.001). A higher proportion of patients with provision of TTR results switched to a NOAC (5.9% vs 4.1%, P=0.49).

CONCLUSIONS

The provision of TTR among patients on warfarin was associated with a discussion about switching from warfarin to a NOAC in those with TTR <65%, but did not result in actual switching to a NOAC, suggesting additional barriers.

Navigating the choice of oral anticoagulation therapy for atrial fibrillation in the NOAC era

Atrial fibrillation (AF) is a major cause of ischaemic stroke. The majority of these strokes can be prevented by treatment with oral anticoagulation therapy. The advent of non-vitamin K antagonist oral anticoagulants (NOACs) has resulted in a choice of therapeutic agents available to physicians for anticoagulation for stroke prevention in patients with AF beyond the long-established vitamin K antagonists (VKAs). Pivotal trials have demonstrated non-inferiority of NOACs compared with VKAs, and in some cases superiority, for the prevention of stroke and systemic embolism in non-valvular AF. Yet there are no direct head-to-head comparator trials for the efficacy of NOACs. Therefore, the question of which oral anticoagulant for each individual patient can present a challenge to physicians. In this review article, we assess which patients with AF require anticoagulation, review the available therapeutic options, assessing the evidence base for each and offering guidance as to patient-specific factors that can influence this choice.

A single institution’s experience with using dabigatran, rivaroxaban and warfarin for prevention of thromboembolism in atrial fibrillation

Background:

Although non-vitamin K antagonist oral anticoagulants (NOACs) are approved for stroke prevention in atrial fibrillation (AF) patients, their use in the local clinical setting has not been well studied. This study aims to evaluate the clinical outcomes of dabigatran, rivaroxaban and warfarin in a tertiary hospital in Singapore.

Methods:

This is a retrospective cohort study with one-year follow-up. A total of 383 patients recruited between June 2011 and December 2014 were studied. Incidents of stroke, systemic embolism and clinically relevant bleeding events were compared between dabigatran, rivaroxaban and warfarin.

Results:

Stroke rates were 5.47% per year with warfarin, 7.27% per year with dabigatran (HR=1.32; 95% CI 0.48−3.64; p=0.591) and 2.76% per year with rivaroxaban (HR=0.49; 95% CI 0.14−1.69; p=0.261). The warfarin group had significantly higher incidence of minor bleeding (62.4% vs 3.64% for dabigatran vs 13.79% for rivaroxaban; p<0.001), major bleeding (3.91% for warfarin, 0.91% for dabigatran, 0% for rivaroxaban; p=0.028) and other adverse events (51.18% for warfarin, 3.64% for dabigatran, 8.28% for rivaroxaban; p<0.001). Incidence of dyspepsia was higher in both NOAC groups compared to warfarin (0% for warfarin, 7.27% for dabigatran, 5.52% for rivaroxaban; p=0.003).

Conclusion:

Stroke and venous thromboembolism rates after one year were comparable among dabigatran, rivaroxaban and warfarin. Warfarin was associated with more bleeding and adverse events while both NOACs were associated with higher rates of dyspepsia. Further study is needed to assess the clinical benefit of NOACs in the Singaporean population.

Permanent discontinuation of non vitamin K oral anticoagulants in real life patients with non-valvular atrial fibrillation

BACKGROUND

Persistence to treatment affects clinical outcomes in patients with chronic disease such as atrial fibrillation (AF).

METHODS

This prospective cohort study included consecutive non-valvular AF patients prescribed with non-vitamin K oral anticoagulants (NOACs) and investigated for any permanent discontinuation at 1-year of this therapy, as well as any reasons for discontinuation.

RESULTS

Overall, 1305 patients were prescribed with dabigatran (N=473), rivaroxaban (N=425) or apixaban (N=407). Of these, 201 patients (15.4%) discontinued NOACs during the first year of treatment. More than 60% of these discontinuations occurred during the first 6months. Reasons for discontinuation included: dyspepsia or abdominal pain in 38 patients (2.9%) and bleeding in 59 (4.5%). Discontinuation for the former occurred earlier (50% within 2months) compared to the latter (66% after the first 4months). The prescription of reduced NOAC doses resulted being an independent predictor of discontinuation (OR 1.74, 95% CI 1.23-2.45, p=0.002). Regarding the use of dabigatran, rivaroxaban and apixaban, the following were observed: discontinuers were 22.0% (95% CI 18.5-25.9), 14.4% (95% CI 11.3-18.0) and 8.8% (95% CI 6.5-12.0), the risk of discontinuation associated with bleeding was 20.2%, 44.3% and 30.6% and dyspepsia or abdominal pain was 35.6%, 1.6% and 0%, respectively.

CONCLUSION

Discontinuation of NOACs in AF patients was relatively common and more than often occurred in the first six months after prescription. Patients treated with reduced doses of NOACs had a higher probability to discontinue compared to those who were prescribed conventional doses.

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.

Cost-effectiveness modelling of novel oral anticoagulants incorporating real-world elderly patients with atrial fibrillation

BACKGROUND

Novel oral anticoagulants (NOACs) expand the treatment options for patients with atrial fibrillation (AF). Their benefits need to be weighed against the risk-benefit ratio in real-world elderly patients, prompting this cost-effectiveness study of NOACs (apixaban, dabigatran, edoxaban and rivaroxaban), warfarin and aspirin for stroke prevention in AF.

METHODS

Applying effectiveness estimates from a network meta-analysis involving over 800,000 patients from randomised controlled trials and observation studies, our Markov model projected cost and health outcomes for a cohort of 65-year-old AF patients over a life-time. We performed subgroup analysis stratified by age (65-74 and ≥75years), with further analysis limited to observational studies involving dabigatran and rivaroxaban.

RESULTS

Compared to warfarin, NOACs (except dabigatran 110) were associated with incremental cost-effectiveness ratios ranging from USD 24,476 to USD 41,448 that were within cost-effectiveness threshold of USD 49,700 (one gross domestic product per capita in Singapore in 2015). Aspirin regimens were dominated. In elderly aged ≥75years, cost effectiveness of NOACs (except apixaban) decreased, owing to worsened performance in safety profile. Analysis limited to observational studies revealed that dabigatran 150 and rivaroxaban were not cost-effective, reflecting increased bleeding risks in non-controlled settings. Threshold analyses revealed that apixaban was no longer cost-effective at two to three times higher bleeding risk.

CONCLUSIONS

Whilst NOACs are cost-effective in the younger elderly compared to warfarin, their benefits appear to be offset by worsened risk profile in older elderly, especially in non-controlled settings. Decisions on appropriate AF treatment should balance treatment-related benefits, risks, and patient preference.

Does novel oral anticoagulant improve anticoagulation for non-valvular atrial fibrillation associated stroke: An inpatient registration study in Shanghai

OBJECTIVE

To summarize the use rate, safety, efficacy of antithrombotics in stroke/transient ischemic attack (TIA) prevention, and reasons for not using dabigatran etexilate (DE) in Shanghai, China.

METHODS

Non-valvular atrial fibrillation (NVAF)-associated stroke patients were prospectively registered as an electronic database. Use rate of antithrombotics and reasons for not using DE were extracted during follow-up. Patients' baseline characteristics, recurrent ischemic stroke/TIA events and bleeding complications were analyzed.

PATIENTS

From April 2012 to August 2014, 110 inpatients with NVAF-associated stroke were studied in our hospital. NVAF was diagnosed by 12-lead electrocardiogram, 24 h Holter and echocardiography.

RESULTS

Before introduction of DE (April 2013), use rates of warfarin and antiplatelets were 28.9% (11/38) and 60.5% (23/38) respectively; after that, use rates of warfarin, DE, and antiplatelets were 20.8% (15/72), 12.5% (9/72), and 43.1% (31/72). The DE did not improve use of anticoagulants (P = 0.639). There were 19 (17.3%) recurrent ischemic stroke events up to October 2015; two (9.5%) in the non-user group, 10 (18.5%) in the antiplatelet group, and seven (20.0%) in the anticoagulants group (P = 0.570). Furthermore, recurrence rates were similar between the DE group (20.0%) and the Warfarin group (20.0%, P = 1.000). The most common reason for not using DE was financial concerns (61.0%), followed by inconvenience to purchase (14.0%) and hemorrhage concerns (11.0%). Two patients using warfarin found fecal occult blood so they stopped warfarin and began to use antiplatelet drugs. No bleeding event occurred in the other groups. Only one patient had side effects (dyspepsia and gastroesophageal reflux) from DE.

CONCLUSION

The use rate of either DE or warfarin in Shanghai was low; DE had not improved anticoagulation therapy for NVAF patients in Shanghai mainly because DE had not been covered by health insurance.

Time in Therapeutic Range and Percentage of International Normalized Ratio in the Therapeutic Range as a Measure of Quality of Anticoagulation Control in Patients With Atrial Fibrillation

BACKGROUND

Time in therapeutic range (TTR), albeit the standard measure of quality of anticoagulation control for warfarin, is underused in everyday clinical practice because of its tedious calculation. In contrast, the percentage of international normalized ratio measurements in range (PINRR) is a convenient alternative. Our objective was to investigate the correlation between PINRR and TTR and whether PINRR has clinical utility for prediction of ischemic stroke and intracranial hemorrhage in a "real-world" atrial fibrillation (AF) cohort.

METHODS

This is an observational study based on a hospital-based AF registry.

RESULTS

Among 1428 Chinese patients with AF who were taking warfarin (76.2 ± 8.7 years; mean CHA₂DS₂-VASc, 4.2 ± 1.6 and HAS-BLED, 2.3 ± 0.9), mean and median TTR values were 38.2% ± 24.4% and 38.8% (interquartile range, 17.9% and 56.2%), respectively. Patients with TTR ≥ 65% (14.8%) had a lower annual risk of ischemic stroke (3.04% per year) than did those with TTR < 65% (5.35% per year). Mean and median PINRR were 34.3% ± 17.1% and 34.2% (interquartile range, 22.7% and 46.0%), respectively. TTR significantly correlated with PINRR in a linear fashion (r = 0.81; P < 0.0001). A cutoff of PINRR ≤ 56.1% was a good discriminator of TTR < 65%, with a high sensitivity (98.3%) and positive predictive value (91.9%). The annual ischemic stroke risk in patients with PINRR > 56.1% was 2.56% per year, lower than those with TTR ≥ 65% (3.04% per year). Patients with PINRR > 56.1% had an annual incidence of intracranial hemorrhage comparable to those with TTR ≥ 65% (0.49% per year vs 0.68% per year).

CONCLUSIONS

Among patients with AF who are taking warfarin, the PINRR is a user-friendly alternative to TTR, having a high sensitivity and positive predictive value in predicting TTR. As with TTR, PINRR is associated with clinical adverse events, ie, ischemic stroke and intracranial hemorrhage.

Clinical and Safety Outcomes of Oral Antithrombotics for Stroke Prevention in Atrial Fibrillation: A Systematic Review and Network Meta-analysis

INTRODUCTION

Novel oral anticoagulants (NOACs) expanded the options for stroke prevention in atrial fibrillation (AF). Earlier studies comparing their relative effectiveness and safety typically do not incorporate age-related differences or postmarketing studies. This study aimed to summarize and compare clinical and safety outcomes of oral antithrombotics for stroke prevention in AF in younger (65-74 years) and older (≥75 years) elderly.

METHODS

We searched PubMed, Embase, and The Cochrane Library from inception through May 1, 2015, for randomized and nonrandomized studies comparing NOACs, warfarin, and aspirin in elderly with AF. Stroke and systemic embolism (SSE) and major bleeding (MB) are the main outcomes. We also studied secondary outcomes of ischemic stroke, all-cause mortality, intracranial bleeding, and gastrointestinal bleeding.

RESULTS

Of 5255 publications identified, 25 randomized controlled trials and 24 nonrandomized studies of 897,748 patients were included. NOACs reduced the risk of SSE compared with warfarin (rate ratios [RRs] range from 0.78-0.82). Relative to SSE, NOACs demonstrated a smaller benefit for ischemic stroke (dabigatran 110 mg, RR 1.08; edoxaban, 1.00; apixaban, 0.99). On the contrary, aspirin was associated with a significantly higher risk of SSE, ischemic stroke, and mortality than warfarin or NOACs (RR > 1), particularly in older elderly. Regarding safety, medium-dose aspirin (100-300 mg daily) and aspirin/clopidogrel combination showed an increased risk of MB compared with warfarin (RR 1.17 and 1.15, respectively), as per dabigatran 150 mg and rivaroxaban in older elderly (RR 1.17 and 1.12, respectively). Among the NOACs, dabigatran 150 mg conferred greater gastrointestinal bleeding risk compared with warfarin (RR 1.51), whereas rivaroxaban (RR 0.73) demonstrated less benefit of reduced intracranial bleeding than other NOACs (RRs range 0.39-0.46).

CONCLUSIONS

Lower rates of SSE and intracranial bleeding were observed with the NOACs compared with warfarin. Dabigatran 150 mg and rivaroxaban were associated with higher rates of MB in older elderly.

Different risk factors for bleeding and discontinuation between dabigatran and rivaroxaban

BACKGROUND

It is unclear whether risk factors for bleeding and discontinuation are different between dabigatran and rivaroxaban.

METHODS AND RESULTS

We enrolled consecutive patients with atrial fibrillation who received dabigatran or rivaroxaban, had a CHADS2 score >1 and creatinine clearance >30ml/min. During this period, only dabigatran and rivaroxaban were available as non-vitamin K oral anticoagulants (NOACs) in our hospital. We compared the clinical and demographic data and the incidence of bleeding for one year between dabigatran group and rivaroxaban group. As a result, the dabigatran group consisted of 177 patients and the rivaroxaban group consisted of 179 patients. The incidence of discontinuation was significantly higher in the dabigatran group than in the rivaroxaban group (27.7% vs. 13.4%, p<0.001). Multivariate analysis, even after propensity score-matching analysis, revealed that there were no independent risk factors for bleeding in the dabigatran group, while in the rivaroxaban group, use of antiplatelet therapy was an independent factor correlating with bleeding.

CONCLUSIONS

The risk factors for bleeding may be different between dabigatran and rivaroxaban. To avoid bleeding, rivaroxaban should be prescribed with caution or avoided in patients using antiplatelet therapy. Upon discontinuation, rivaroxaban may be more favorable than dabigatran.

Impact of Antithrombotic Therapy in Atrial Fibrillation on the Presentation of Coronary Artery Disease

Background

Little is known about whether atrial fibrillation is a presentation of coronary disease. There is a paucity of knowledge about their causal relationship and also the impact of different antithrombotic strategies on the subsequent presentation of symptomatic coronary disease.

Methods and Results

We studied 7,526 Chinese patients diagnosed with non-valvular atrial fibrillation and no documented history of coronary artery disease. The primary endpoint was the new occurrence of coronary artery disease—either stable coronary artery disease or acute coronary syndrome. After a mean follow-up of 3.2±3.5 years (24,071 patient-years), a primary endpoint occurred in 987 patients (13.1%). The overall annual incidence of coronary artery disease was 4.10%/year. No significant differences in age, sex, and mean CHA₂DS₂-VASc score were observed between patients with and without the primary endpoint. When stratified according to the antithrombotic strategies applied for stroke prevention, the annual incidence of coronary artery disease was 5.49%/year, 4.45%/year and 2.16%/year respectively in those prescribed no antithrombotic therapy, aspirin, and warfarin. Similar trends were observed in patients with acute coronary syndromes. Diabetes mellitus, smoking history and renal failure requiring dialysis were predictors for primary endpoint in all antithrombotic therapies.

Conclusion

In patients with non-valvular atrial fibrillation, there is a modest association with coronary artery disease. Patients prescribed warfarin had the lowest risk of new onset coronary artery disease.

Risk of gastrointestinal bleeding associated with oral anticoagulants: population based retrospective cohort study

OBJECTIVES

To determine the real world safety of dabigatran or rivaroxaban compared with warfarin in terms of gastrointestinal bleeding.

DESIGN

Retrospective cohort study.

SETTING

Large administrative database of commercially insured people in United States from 1 October 2010 through 31 March 2012.

PARTICIPANTS

Enrollees with a prescription of warfarin, dabigatran, or rivaroxaban between 1 October 2010 and 31 March 2012, who were aged 18 years or older, had continuous enrollment and no oral anticoagulant use during the six months before the entry date, with known age and sex, and with no gastrointestinal bleeding for at least six months before the cohort entry date. The final study sample of 46,163 patients included 4907 using dabigatran, 1649 using rivaroxaban, and 39,607 using warfarin.

MAIN OUTCOME MEASURE

Time to gastrointestinal bleeding. Hazard ratios were derived from Cox proportional hazard models with propensity score weighting and robust estimates of errors.

RESULTS

Dabigatran users tended to be older (dabigatran v rivaroxaban v warfarin: 62.0 v 57.6 v 57.4 years) and more likely to be male (69% v 49% v 53%). The rate of gastrointestinal bleeding was highest among dabigatran users and lowest among rivaroxaban users (dabigatran v rivaroxaban v warfarin: 9.01 v 3.41 v 7.02 cases per 100 person years). After adjustment for potentially confounding covariates, there was no evidence of a statistically significant difference in the risk of gastrointestinal bleeding between dabigatran and warfarin users (adjusted hazard ratio 1.21, 95% confidence interval 0.96 to 1.53) or between rivaroxaban and warfarin users (0.98, 0.36 to 2.69).

CONCLUSIONS

Although rates of gastrointestinal bleeding seem to be similar in this commercially insured sample of adults in the United States, we cannot rule out as much as a 50% increase in the risk of gastrointestinal bleeding with dabigatran compared with warfarin or a more than twofold higher risk of bleeding with rivaroxaban compared with warfarin.