Comparison of the Effectiveness and Safety of Apixaban, Dabigatran, Rivaroxaban, and Warfarin in Newly Diagnosed Atrial Fibrillation

COVID-19 Diagnosis, Oral Anticoagulation, and Stroke Risk in Patients with Atrial Fibrillation

BACKGROUND

Coronavirus disease 2019 (COVID-19) has been associated with an increased risk of stroke. It remains unclear whether the risk of stroke associated with a diagnosis of COVID-19 differed with oral anticoagulation (OAC) use. The aim of this study was to evaluate the association between COVID-19 infection, OAC use, and stroke in patients with atrial fibrillation (AF).

METHODS

A retrospective cohort study was conducted in individuals with established AF using data from Optum's deidentified Clinformatics® Data Mart Database. Cox proportional hazard models with time-dependent variables were employed to assess the association between possession of OAC, COVID-19 diagnosis in both inpatient and outpatient setting, and time to ischemic stroke.

RESULTS

A total of 561,758 individuals aged 77 ± 10 were included in the study, with a mean follow up time of 1.3 years. OAC use was associated with a reduced stroke risk [hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.82-0.88]. COVID-19 infection was associated with an increased risk of stroke (HR 2.11, 95% CI 1.87-2.38); this increased risk was particularly pronounced for patients diagnosed with an inpatient diagnosis of COVID-19 (HR 3.95, 95% CI 3.33-4.68). There was no significant interaction between OAC use and COVID-19 diagnosis (p value = 0.96). As a result, the relative increase in stroke risk associated with COVID-19 did not differ between patients on OAC (HR 2.12; 95% CI 1.71-2.62) and those not on OAC (HR 2.11; 95% CI 1.83-2.43).

CONCLUSION

In a nationwide sample of patients with established AF, we found the relative increase in stroke risk associated with COVID-19 was independent of OAC use.

Efficient Generation of Protein Pockets with PocketGen

Designing protein-binding proteins plays an important role in drug discovery. However, AI-based design of such proteins is challenging due to complex ligand-protein interactions, flexibility of ligand molecules and amino acid side chains, and sequence-structure dependencies. We introduce PocketGen, a deep generative model that produces both the residue sequence and atom structure of the protein regions where interactions with ligand molecules occur. PocketGen ensures sequence-structure consistency by using a graph transformer for structural encoding and a sequence refinement module based on a protein language model. The bilevel graph transformer captures interactions at multiple granularities across atom, residue, and ligand levels. To enhance sequence refinement, PocketGen integrates a structural adapter with the protein language model, ensuring consistency between structure-based and sequence-based predictions. Results show that PocketGen can generate high-fidelity protein pockets with superior binding affinity and structural validity. It is ten times faster than physics-based methods and achieves a 95% success rate, defined as the percentage of generated pockets with higher binding affinity than reference pockets, along with achieving an amino acid recovery rate exceeding 64%.

A Case of Direct-Acting Oral Anticoagulant-Induced Intramural Colon Hematoma Successfully Treated by Laparoscopic Surgery

Intramural intestinal hematoma is a rare disease, one of the triggering factors of which is the use of anticoagulants. In previous reports, most patients were on treatment with warfarin. Herein, we report a case of direct-acting oral anticoagulant (DOAC)-induced intramural hematoma of the ascending colon in a patient refractory to conservative treatment and required laparoscopic right hemicolectomy. An 80-year-old male patient with a history of atrial fibrillation and cerebral infarction, on treatment with apixaban, was brought to our hospital with the chief complaints of abdominal pain, vomiting, and melena. Imaging revealed the cause of symptoms to be intestinal obstruction caused by a mass lesion on the wall of the ascending colon. We initially opted for conservative treatment with discontinuation of apixaban and insertion of an ileus tube. Intestinal dilatation findings showed improvement; however, subsequent imaging examinations did not reveal the shrinkage of a lesion in the ascending colon. If the mass was not removed, recurrence of bowel obstruction symptoms was expected, so we decided to perform surgical intervention. A laparoscopic right hemicolectomy was performed, and an intramural hematoma of the ascending colon was diagnosed based on the excised specimen. He needed a blood transfusion for anemia but was discharged on postoperative day 14 with no other complications. DOACs are now widely used in patients with atrial fibrillation, and the risk of bleeding as a side effect is extremely low compared to conventional anticoagulants, including warfarin. However, when abdominal pain occurs, as in the present case, an intramural hematoma should be considered in the differential diagnosis. There is no established treatment plan for intestinal intramural hematoma. Although conservative treatment is effective in some cases, it is difficult to evaluate the risk of bleeding associated with DOACs using coagulation tests. Even if conservative treatment is selected, it is essential to determine surgical resection, if necessary, based on the clinical course and imaging and blood test findings.

Medicare drug price negotiation: The complexities of selecting therapeutic alternatives for estimating comparative effectiveness

Under the 2022 Inflation Reduction Act, the Centers for Medicare and Medicaid Services (CMS) are able to negotiate prices for topselling drugs in the Medicare Part B and D programs. In determining initial price offers, CMS will compare the prices and clinical benefits of the drugs subject to negotiation to the prices and clinical benefits of therapeutic alternatives. Despite the central role that the selection of therapeutic alternatives will play in the price negotiations, the available guidance published by CMS provides few details about how the organization will undertake this process, which will be particularly complex for drugs approved for more than one indication. To better inform the selection process, we identified all US Food and Drug Administration-approved indications for the first 10 drugs subject to negotiation. Using 2020-2021 Medicare claims data, we identified Medicare Part D beneficiaries using each of the 10 drugs. We extracted medical claims with diagnosis codes for each of the approved indications to report the relative treated prevalence of use by indication for each drug. We reviewed published clinical guidelines to identify relevant therapeutic alternatives for each of the indications. We integrated the evidence on the relative treated prevalence of indications and clinical guidelines to propose therapeutic alternatives for each of the 10 drugs. We describe challenges that CMS may face in selecting therapeutic alternatives.

Risk of Major Bleeding Associated with Concomitant Direct-Acting Oral Anticoagulant and Clopidogrel Use: A Retrospective Cohort Study

BACKGROUND AND AIM

Combined anticoagulant-antiplatelet therapy is often indicated in adults with cardiovascular disease and atrial fibrillation or venous thromboembolism. The study aim was to assess the comparative risk of bleeding between rivaroxaban and apixaban when combined with clopidogrel.

METHODS

We conducted a retrospective cohort study of commercially insured US adults newly treated with a combination of rivaroxaban+clopidogrel or apixaban+clopidogrel (2015-2018) using Merative™ Marketscan Research Databases. We used propensity score-based inverse probability of treatment weighting (IPTW) to balance the treatment groups. Weighted Cox proportional hazards regression was used to estimate the risk of major bleeding.

RESULTS

The study cohort included 2895 rivaroxaban+clopidogrel users and 3628 apixaban+clopidogrel users. The median (range) duration of follow up was 61 (73) days. Rivaroxaban+clopidogrel users had a similar risk of major bleeding compared with apixaban+clopidogrel users (IPTW incidence rate per 100 person-years 7.96 vs 7.38; IPTW hazard ratio [HR] 1.13 [95% CI 0.78-1.63]). In the subcohort of adults who were treated with DOAC or clopidogrel monotherapy prior to the combined therapy, the risk of major bleeding did not differ by the drug of monotherapy (IPTW HR for rivaroxaban+clopidogrel group: 0.66 [95% CI 0.33-1.32]; IPTW HR for apixaban+clopidogrel group: 1.10 [95% CI 0.55-2.23]) CONCLUSIONS: In our study of commercially insured US adults, the concomitant use of rivaroxaban+clopidogrel and apixaban+clopidogrel conferred a similar risk of major bleeding. DOAC versus clopidogrel monotherapy prior to the concomitant therapy did not influence the risk of major bleeding.

Effect of China national centralized drug procurement policy on anticoagulation selection and hemorrhage events in patients with AF in Suining

Background: Launched in March 2019, the National Centralized Drug Procurement (NCDP) initiative aimed to optimize the drug utilization framework in public healthcare facilities. Following the integration of Non-Vitamin K Antagonist Oral Anticoagulants (NOACs) into the procurement catalog, healthcare establishments in Suining swiftly transitioned to the widespread adoption of NOACs, beginning 1 March 2020. Objective: This study aims to comprehensively assess the impact of the NCDP policy on the efficacy of anticoagulation therapy, patient medication adherence, and the incidence of hemorrhagic events in individuals with non-valvular atrial fibrillation (NVAF) residing in Suining. The analysis seeks to elucidate the broader impacts of the NCDP policy on this patient demographic. Methods: This study analyzed patient hospitalization records from the Department of Cardiology at Suining County People's Hospital, spanning 1 January 2017, to 30 June 2022. The dataset included demographic details (age, sex), type of health insurance, year of admission, hospitalization expenses, and comprehensive information on anticoagulant therapy utilization. The CHA2DS2-VASc scoring system, an established risk assessment tool, was used to evaluate stroke risk in NVAF patients. Patients with a CHA2DS2-VASc score of 2 or higher were categorized as high-risk, while those with scores below 2 were considered medium or low-risk. Results: 1. Treatment Cost Analysis: The study included 3,986 patients diagnosed with NVAF. Following the implementation of the NCDP policy, a significant increase in the average treatment cost for hospitalized patients was observed, rising from 8,900.57 ± 9,023.02 CNY to 9,829.99 ± 10,886.87 CNY (p < 0.001). 2. Oral Anticoagulant Utilization: Overall, oral anticoagulant use increased from 40.02% to 61.33% post-NCDP (p < 0.001). Specifically, NOAC utilization among patients dramatically rose from 15.41% to 90.99% (p < 0.001). 3. Hemorrhagic Events: There was a significant decrease in hemorrhagic events following the NCDP policy, from 1.88% to 0.66% (p = 0.01). Hypertension [OR = 1.979, 95% CI (1.132, 3.462), p = 0.017], history of stroke [OR = 1.375, 95% CI (1.023, 1.847), p = 0.035], age ≥65 years [OR = 0.339, 95% CI (0.188, 0.612), p < 0.001], combination therapy of anticoagulants and antiplatelets [OR = 3.620, 95% CI (1.752, 7.480), p < 0.001], hepatic and renal insufficiency [OR = 4.294, 95% CI (2.28, 8.084), p < 0.001], and the NCDP policy [OR = 0.295, 95% CI (0.115, 0.753), p = 0.011] are significant risk factors for bleeding in patients with atrial fibrillation. 4. Re-hospitalization and Anticoagulant Use: Among the 219 patients requiring re-hospitalization, there was a notable increase in anticoagulant usage post-NCDP, from 36.07% to 59.82% (p < 0.001). NOACs, in particular, saw a substantial rise in usage among these patients, from 11.39% to 80.92% (p < 0.001). 5. Anticoagulant Type Change: The NCDP policy [OR = 28.223, 95% CI (13.148, 60.585), p < 0.001] and bleeding events [OR = 27.772, 95% CI (3.213, 240.026), p = 0.003] were significant factors influencing the alteration of anticoagulant medications in patients. Conclusion: The NCDP policy has markedly improved anticoagulation management in patients with AF. This policy has played a crucial role in enhancing medication adherence and significantly reducing the incidence of hemorrhagic events among these patients. Additionally, the NCDP policy has proven to be a key factor in guiding the selection and modification of anticoagulant therapies in the AF patient population.

COVID-19 pandemic and initiation of treatment for atrial fibrillation: a nationwide analysis of claims data

BACKGROUND

The COVID-19 pandemic profoundly disrupted the delivery of medical care. It remains unclear whether individuals diagnosed with new onset disease during the pandemic were less likely to initiate treatments after diagnosis. We sought to evaluate changes in the treatment initiation of patients newly diagnosed with atrial fibrillation (AF) after the onset of the COVID-19 pandemic.

METHODS

In this retrospective cohort study, we identified individuals with incident AF from 01/01/2016-09/30/2021 using Optum's de-identified Clinformatics® Data Mart Database. The primary outcome was initiation of oral anticoagulation (OAC) within 30 days of AF diagnosis. Secondary outcomes included initiation of OAC within 180 days of diagnosis, initiation of warfarin, direct oral anticoagulants (DOACs), rhythm control medications and electrical cardioversion within 30 days of diagnosis. We constructed interrupted time series analyses to examine changes in the outcomes following the onset of the pandemic.

RESULTS

A total of 573,524 patients (age 73.0 ± 10.9 years) were included in the study. There were no significant changes in the initiation of OAC, DOAC, and rhythm control medications associated with the onset of the pandemic. There was a significant decrease in initiation of electrical cardioversion associated with the onset of the pandemic. The rate of electronic cardioversion within 30 days of diagnosis decreased by 4.9% per 1,000 patients after the onset of the pandemic and decreased by about 35% in April 2020, compared to April 2019, from 5.53% to 3.58%.

CONCLUSION

The COVID-19 pandemic did not affect the OAC initiation within 30 days of AF diagnosis but was associated with a decline in the provision of procedures for patients newly diagnosed with AF.

Benefits and Harms of Standard Versus Reduced-Dose Direct Oral Anticoagulant Therapy for Older Adults With Multiple Morbidities and Atrial Fibrillation

Background Dose reduction of direct oral anticoagulant (DOAC) medications is inconsistently applied to older adults with multiple morbidities, potentially due to perceived harms and unknown benefits of standard dosing. Methods and Results Using 2013 to 2017 US Medicare claims linked to Minimum Data Set records, we conducted a retrospective cohort study. We identified DOAC initiators (apixaban, dabigatran, rivaroxaban) aged ≥65 years with nonvalvular atrial fibrillation residing in a nursing home. We estimated inverse-probability of treatment weights for DOAC dose using propensity scores. We examined safety (hospitalization for major bleeding) and effectiveness outcomes (all-cause mortality, thrombosis [myocardial infarction, stroke, systemic embolism, venous thromboembolism]). We estimated hazard ratios (HRs) and 95% CIs using cause-specific hazard-regression models. Of 21 878 DOAC initiators, 48% received reduced dosing. The mean age of residents was 82.0 years, 66% were female, and 31% had moderate/severe cognitive impairment. After estimating inverse-probability of treatment weights, standard dosing was associated with a higher rate of bleeding (HR, 1.18 [95% CI, 1.03-1.37]; 9.4 versus 8.0 events per 100 person-years). Standard-dose therapy was associated with the highest rates of bleeding among those aged >80 years (9.1 versus 6.7 events per 100 person-years) and with a body mass index <30 kg/m2 (9.4 versus 7.4 events per 100 person-years). There was no association of dosing with mortality (HR, 0.99 [95% CI, 0.96-1.06]) or thrombotic events (HR, 1.16 [95% CI, 0.96-1.41]). Conclusions In this nationwide study of nursing home residents with nonvalvular atrial fibrillation, we found a higher rate of bleeding and little difference in effectiveness of standard versus reduced-dose DOAC treatment. Our results support the use of reduced-dose DOACs for many older adults with multiple morbidities.

Utilization outcomes of direct oral anticoagulants in Medicare patients

OBJECTIVE

To compare the adherence, persistence, discontinuation and switching rates of direct oral anticoagulants (DOACs) for Medicare patients with non-valvular atrial fibrillation (NVAF) or venous thromboembolism (VTE).

METHODS

This was retrospective observational cohort study design. Medicare Part D claims files were used for the study duration (2015-2018). Inclusion-exclusion criteria were applied to identify the NVAF and VTE sample using dabigatran, rivaroxaban, apixaban, edoxaban and warfarin during the identification period (2016-2017). Outcomes of adherence, persistence, time to non-persistence and time to discontinuation were assessed in those who did not switch the index drug in the follow-up period (365 days from the index date). Switching rates were assessed in those who switched the index drug at least once in the aforementioned follow-up period. Descriptive statistics were conducted for all the outcomes, and comparisons were made using t-tests, chi-square, and ANOVA. Logistic regression was conducted to compare the odds of being adherent and the odds of switching in NVAF and VTE patient cohorts.

RESULTS

Of all the DOACs, patients with NVAF or VTE were most adherent to apixaban (PDC = 76.88). Among all the DOACs, non-persistence and discontinuation rates were highest for warfarin. Majority of the switches were reported from dabigatran to other DOAC and to apixaban from other DOAC. Despite the better utilization outcomes reported for apixaban users, Medicare plans covered rivaroxaban favorably. It was associated with the lowest mean amount paid by the patient (NVAF: $76; VTE: $59), and the highest mean amount paid by the plans (NVAF: $359; VTE: $326).

CONCLUSION

Medicare plans need to consider adherence, persistence, discontinuation and switching rates of DOACs to make the coverage decisions.

Effectiveness and safety of oral anticoagulants for non-valvular atrial fibrillation: a population-based cohort study in primary healthcare in Catalonia

Objectives: Our objective was to analyse effectiveness and safety of oral anticoagulants (OAC) for stroke prevention in non-valvular atrial fibrillation. Material and methods: Population-based cohort study including adults initiating oral anticoagulants, either direct oral anticoagulants (DOAC) or vitamin K antagonists (VKA), during 2011-2020. Data source: SIDIAP, capturing information from the electronic health records of Primary Health Care in Catalonia, Spain. Study outcomes: stroke, cerebral and gastrointestinal (GI) haemorrhage, assessed by patients' subgroups according to different clinical characteristics. Results: We included 90,773 patients. Male sex, older than 75, previous event, peripheral artery disease, deep vein thrombosis, or receiving antiplatelets, antidiabetics or proton pump inhibitors (PPI) was associated with higher stroke risk. For DOAC-treated, treatment switch increased stroke risk, while being adherent had a protective effect. Men, antidiabetic treatment or a previous event increased the risk of cerebral bleeding. Receiving direct oral anticoagulants had a protective effect in comparison to vitamin K antagonists. For DOAC-treated, treatment switch increased, and adherence decreased the bleeding risk. Men, people with chronic kidney disease or a previous event posed an increased risk of gastrointestinal bleeding, whereas receiving PPI had a protective effect. For DOAC-treated, switch was associated with a higher bleeding risk. Conclusion: Being men, a previous event and DOAC-switch posed a higher risk for all study outcomes. direct oral anticoagulants had a protective effect against cerebral bleeding in comparison to vitamin K antagonists. Adherence to direct oral anticoagulants resulted in lower risk of stroke and cerebral bleeding. We found no differences in the risk of stroke and gastrointestinal bleeding when we compared direct oral anticoagulants vs. vitamin K antagonists.

Comparative outcomes associated with rivaroxaban versus warfarin use in elderly patients with atrial fibrillation or acute venous thromboembolism managed in the United States: a systematic review of observational studies

BACKGROUND

Advancing age is a risk factor for developing non-valvular atrial fibrillation (NVAF) or acute venous thromboembolism (VTE). We assessed the comparative effectiveness, safety, costs, and healthcare utilization associated with rivaroxaban versus warfarin in patients of advanced age managed in the United States (US).

METHODS

We conducted a systematic review of Medline and Embase through April 2023 to identify real-world evidence (RWE) studies of older adults (at least 65+ years of age) with either NVAF or VTE who received either rivaroxaban or warfarin in the US and reported an outcome of stroke or systemic embolism (SSE), ischemic stroke (IS), recurrent VTE, major bleeding, intracranial hemorrhage, costs, or healthcare resource utilization. We classified each outcome of interest per study as "positive" (lower risk), "negative" (higher risk), or "neutral" based upon the summary effect size of rivaroxaban versus warfarin.

RESULTS

Twenty-nine RWE studies met inclusion criteria, mostly (83%) in NVAF populations. For SSE with rivaroxaban versus warfarin, 68.8% of studies showed positive effects and 31.2% showed neutral outcome. For major bleeding, 57.7% showed neutral effects, 38.5% showed negative effects, and 3.8% of studies showed positive effects with rivaroxaban versus warfarin. Of the two studies reporting cost data, both were positive, showing lower costs for SSE for rivaroxaban versus warfarin and neutral cost for major bleeding costs.

CONCLUSIONS

This systematic review supports findings from subgroup analyses of randomized controlled trials that, compared with warfarin, rivaroxaban is associated with generally neutral or positive effects on thrombosis and a mixed picture on bleeding outcomes in older adults with either NVAF or VTE treated in the United States.

Association between genetic polymorphisms in fibrinogen genes and bleeding risk in patients treated with direct oral anticoagulants

Introduction

This study aimed to investigate the association between polymorphisms in fibrinogen genes and bleeding risk in patients receiving direct oral anticoagulants (DOACs).

Method

Patients treated with DOACs from June 2018 to December 2021 were enrolled in the study. Genotyping was done for rs2070011, rs6050, and rs2070022 in fibrinogen alpha chain (FGA); rs1800788, rs4220, and rs4463047 in fibrinogen beta chain (FGB); and rs2066865 and rs1800792 in fibrinogen gamma chain (FGG), along with F2 rs5896 and F10 rs5960. Multivariable logistic regression analysis was performed to investigate the risk factors for bleeding and to develop a risk scoring system.

Results

A total of 468 patients were included in the analysis, 14 of whom experienced major bleeding and 36 experienced clinically relevant non-major bleeding. In the multivariable analysis, overdose, anaemia, F2 rs5896, and FGG rs1800792 were found to be significantly associated with bleeding risk. Specifically, patients with the TT genotype of F2 rs5896 and the CC genotype of FGG rs1800792 had 2.1 times (95% confidence interval [CI] 1.1-3.9) and 2.7 times (95% CI 1.2-5.9) higher bleeding risk than the C allele and T allele carriers, respectively. Based on the risk scoring system, patients with 0, 1, 2, 3, 4, and 5 points were predicted to have 5.2%, 10.8%, 22.4%, 32.3%, 42.3%, and 61.8% of bleeding risk, respectively.

Conclusion

To our knowledge, this is the first study to investigate the effects of polymorphisms in fibrinogen genes on DOAC response. After validation, these results will be useful for personalised DOAC therapy.

Comparative Effectiveness and Safety of Direct Oral Anticoagulants and Warfarin in Patients With Atrial Fibrillation and Chronic Liver Disease: A Nationwide Cohort Study

BACKGROUND

The benefit-risk profile of direct oral anticoagulants (DOACs) compared with warfarin, and between DOACs in patients with atrial fibrillation (AF) and chronic liver disease is unclear.

METHODS

We conducted a new-user, retrospective cohort study of patients with AF and chronic liver disease who were enrolled in a large, US-based administrative database between January 1, 2011, and December 31, 2017. We assessed the effectiveness and safety of DOACs (as a class and individually) compared with warfarin, and between DOACs in patients with AF and chronic liver disease. The primary outcomes were hospitalization for ischemic stroke/systemic embolism and hospitalization for major bleeding. Inverse probability treatment weights were used to balance the treatment groups on measured confounders.

RESULTS

Overall, 10 209 participants were included, with 4421 (43.2%) on warfarin, 2721 (26.7%) apixaban, 2211 (21.7%) rivaroxaban, and 851 (8.3%) dabigatran. The incidence rates per 100 person-years for ischemic stroke/systemic embolism were 2.2, 1.4, 2.6, and 4.4 for DOACs as a class, apixaban, rivaroxaban, and warfarin, respectively. The incidence rates per 100 person-years for major bleeding were 7.9, 6.5, 9.1, and 15.0 for DOACs as a class, apixaban, rivaroxaban, and warfarin, respectively. After inverse probability treatment weights, the risk of hospitalization for ischemic stroke/systemic embolism was significantly lower between DOACs as a class (hazard ratio [HR], 0.64 [95% CI, 0.46-0.90]) or apixaban (HR, 0.40 [95% CI, 0.19-0.82]) compared with warfarin, but not significantly different between rivaroxaban versus warfarin (HR, 0.76 [95% CI, 0.47-1.21]) or rivaroxaban versus apixaban (HR, 1.73 [95% CI, 0.91-3.29]). Compared with warfarin, the risk of hospitalization for major bleeding was lower with DOACs as a class (HR, 0.69 [95% CI, 0.58-0.82]), apixaban (HR, 0.60 [95% CI, 0.46-0.78]), and rivaroxaban (HR, 0.79 [95% CI, 0.62-1.0]). However, the risk of hospitalization for major bleeding was higher for rivaroxaban versus apixaban (HR, 1.59 [95% CI, 1.18-2.14]).

CONCLUSIONS

Among patients with AF and chronic liver disease, DOACs as a class were associated with lower risks of hospitalization for ischemic stroke/systemic embolism and major bleeding versus warfarin. However, the incidence of clinical outcomes among patients with AF and chronic liver disease varied between individual DOACs and warfarin, and in head-to-head DOAC comparisons.

Long-term comparative effectiveness and safety of dabigatran, rivaroxaban, apixaban and edoxaban in patients with atrial fibrillation: A nationwide cohort study

Background: Although non-vitamin K antagonist oral anticoagulants (NOACs) are recommended over vitamin K antagonists (VKAs) in atrial fibrillation (AF) management, direct long-term head-to-head comparisons are lacking. Therefore, their risk-benefit profiles were investigated compared to VKAs and between NOACs. Methods: AF patients initiating anticoagulation between 2013-2019 were identified in Belgian nationwide data. Inverse probability of treatment weighted Cox regression was used to investigate effectiveness and safety outcomes and were additionally stratified by NOAC dose. Results: Among 254,478 AF patients (328,796 person-years of follow-up), NOACs were associated with significantly lower risks of stroke or systemic embolism (stroke/SE) (hazard ratio (HR) 0.68, 95% confidence interval (CI) (0.64-0.72)), all-cause mortality (HR 0.76, 95%CI (0.74-0.79)), major or clinically relevant non-major bleeding (MB/CRNMB) (HR 0.94, 95%CI (0.91-0.98)) and intracranial hemorrhage (HR 0.73, 95%CI (0.66-0.79)), but non-significantly different risks of myocardial infarction, gastrointestinal and urogenital bleeding compared to VKAs. Despite similar stroke/SE risks, dabigatran and apixaban were associated with significantly lower MB/CRNMB risks compared to rivaroxaban (HR 0.86, 95%CI (0.83-0.90); HR 0.86, 95%CI (0.83-0.89), respectively) and edoxaban (HR 0.91, 95%CI (0.83-0.99); HR 0.86, 95%CI (0.81-0.91), respectively), and apixaban with significantly lower major bleeding risks compared to dabigatran (HR 0.86, 95%CI (0.80-0.92)) and edoxaban (HR 0.79, 95%CI (0.72-0.86)). However, higher mortality risks were observed in some risk groups including with apixaban in patients with diabetes or concomitantly using digoxin compared to dabigatran and edoxaban, respectively. Conclusion: NOACs had better long-term risk-benefit profiles than VKAs. While effectiveness was comparable, apixaban was overall associated with a more favorable safety profile followed by dabigatran.

Risk of thromboembolic events in relation to the management of anticoagulant and antiagregant therapy in patients subjected to endoscopic retrograde cholangiopancreatography

BACKGROUND AND OBJECTIVES

The main clinical practice guidelines recommend adequate periprocedural withdrawal and reintroduction of antithrombotic drugs in case of invasive techniques. The main objective of this study was to assess whether, in patients receiving anticoagulant or antiplatelet therapy, the suppression or reduction of the pharmacological dose for the performance of endoscopic retrograde cholangiopancreatography (ERCP) implies a greater risk of thromboembolic events.

PATIENTS AND METHODS

A prospective observational study was carried out, which included 644ERCP performed with therapeutic intention during 2019 at the Reina Sofía University Hospital with follow-up during the 30days after the endoscopic intervention.

RESULTS

Six patients presented a thromboembolic event, finding no differences between the incorrect withdrawal/reintroduction of antithrombotic treatment and a higher proportion of thromboembolic or hemorrhagic events after the procedure (P>.05). The incidence of thrombotic events was significantly higher in patients treated with heparin or apixaban (P=.001), as well as with a history of atrial fibrillation (P=.05), rheumatic valve disease (P=.037) and recurrent pulmonary embolism (P=.035), this being also an independent risk factor. Likewise, the incidence of hemorrhage in the 30days post-sphincterotomy was significantly lower in those with implantation of a biliary prosthesis (P=.04).

CONCLUSIONS

Inadequate periprocedural management of antithrombotic therapy is not associated with a significant increase in the incidence of thromboembolic events in the 30days after ERCP. However, close follow-up and surveillance during the days after this is essential in those patients with a condition that significantly increases the risk of thrombosis.

American Indians and atrial fibrillation

The American Indian population is known to experience high rates of cardiovascular disease and have a heightened vulnerability to severe outcomes driven by an overall poor health status and lower access to quality health care. Our group has previously published an analysis demonstrating that American Indians have the highest risk of atrial fibrillation (AF), as well as of AF-related stroke, when compared with other races and ethnicities. Despite this, AF in this population has not been extensively studied and additional publications are scarce. Our review article provides an up-to-date summary of the relevant literature addressing the relationship between race, ethnicity, and AF by focusing on American Indians.

Gastrointestinal Bleeding on Oral Anticoagulation: What is Currently Known

Gastrointestinal bleeding (GIB) is the most common type of bleeding occurring in patients on oral anticoagulation. A meta-analysis of the landmark randomized controlled trials (RCTs) for patients with atrial fibrillation demonstrated that direct oral anticoagulants (DOACs) were associated with higher GIB rates compared to warfarin. However, significant heterogeneity existed between studies. While rivaroxaban, high-dose dabigatran, and high-dose edoxaban were associated with higher GIB rates than warfarin, GIB rates were similar between warfarin users and both apixaban and low-dose dabigatran users. Additionally, previous observational studies have yielded conflicting reports on whether GIB rates differ between warfarin and DOACs. Meta-analyses of observational studies demonstrated that warfarin is associated with lower rates of GIB compared to rivaroxaban, similar or lower rates compared to dabigatran, and higher rates compared to apixaban. Importantly, no RCT has compared individual DOACs directly and due to the different selection criteria of the initial RCTs, indirect comparisons between DOACs using these studies are unreliable. The best available information of comparisons between individual DOACs is therefore limited to observational studies. There is mounting evidence that suggests that rivaroxaban is associated with a higher risk of GIB compared to other DOACs. Finally, GIB induced by oral anticoagulation may have some positive aspects. Interestingly, there are studies that indicate oral anticoagulation facilitates colorectal cancer detection. Furthermore, results from RCTs and observational studies suggest that warfarin may even decrease the incidence of cancer.

Impact of comparative effectiveness research on Medicare coverage of direct oral anticoagulants

Aim: To evaluate the association of comparative effectiveness research with Medicare coverage of direct oral anticoagulants. Materials & methods: A literature review for direct oral anticoagulants was conducted from 2011 to 2017. Monthly prescription drug plan and formulary files (n = 28) were used to conduct change-point analysis and assess each outcome variable. Results: Up to 2013, studies showed that dabigatran was more effective than rivaroxaban. In 2015, apixaban was shown to be the safest and most effective drug in comparison with all direct oral anticoagulants. In 2016-2017, dabigatran and apixaban were shown to have similar efficacy. Approximately 75% of plans covered dabigatran under tier 3 until 2015. From 2011 to 2017, less than 30% of plans required prior authorizations, 50% imposed quantity limits and mean copayment was lowest for rivaroxaban. Conclusion: Consistent with comparative effectiveness research, Medicare plans covered apixaban more favorably and edoxaban less favorably. However, discrepancies in comparative effectiveness research translation were found for rivaroxaban and dabigatran.

Group based trajectory modeling to assess adherence to oral anticoagulants among atrial fibrillation patients with comorbidities: a retrospective study

BACKGROUND

Poor adherence to oral anticoagulants is a significant problem in atrial fibrillation (AF) patients with comorbidities as it increases the risk for cardiac and thromboembolic events.

AIM

The primary objective was to evaluate adherence to direct oral anticoagulants (DOACs) or warfarin using group-based trajectory modeling (GBTM). The secondary objective was to identify the predictors of adherence to oral anticoagulants. Finally, to report the drug interactions with DOACs/warfarin.

METHOD

This retrospective study was conducted among continuously enrolled Medicare Advantage Plan members from January 2016-December 2019. AF patients with comorbid hypertension, diabetes and hyperlipidemia using warfarin/DOACs were included. Monthly adherence to DOAC/warfarin was measured using proportion of days covered (PDC) and then modeled in a logistic GBTM to identify the distinct patterns of adherence. Logistic regression model was conducted to identify the predictors of adherence to oral anticoagulants adjusting for all baseline characteristics. Concomitant use of DOACs/warfarin with CYP3A4,P-gp inhibitors were measured.

RESULTS

Among 317 patients, 137 (43.2%) and 79 (24.9%) were DOAC, and warfarin users, respectively. The adherence trajectory model for DOACs included gradual decline (40.4%), adherent (38.8%), and rapid decline (20.8%). The adherence trajectories for warfarin adherence included gradual decline (8.9%), adherent (59.4%), and gaps in adherence (21.7%). Predictors of adherence included type of oral anticoagulant, stroke risk score, low-income subsidy, and baseline PDC. CYP3A4,P-gp drugs were co-administered with DOACs /warfarin resulting in adverse events.

CONCLUSION

Adherence to oral anticoagulants is suboptimal. Interventions tailored according to past adherence trajectories may be effective in improving patient's adherence.

Effectiveness and Safety of Apixaban in over 3.9 Million People with Atrial Fibrillation: A Systematic Review and Meta-Analysis

Background: There is a plethora of real-world data on the safety and effectiveness of direct-acting oral anticoagulants (DOACs); however, study heterogeneity has contributed to inconsistent findings. We compared the effectiveness and safety of apixaban with those of other direct-acting oral anticoagulants (DOACs) and vitamin K antagonists (VKA e.g., warfarin). Methods: A systematic review and meta-analysis was conducted retrieving data from PubMed, SCOPUS and Web of Science from January 2009 to December 2021. Studies that evaluated apixaban (intervention) prescribed for adults (aged 18 years or older) with AF for stroke prevention compared to other DOACs or VKAs were identified. Primary outcomes included stroke/systemic embolism (SE), all-cause mortality, and major bleeding. Secondary outcomes were intracranial haemorrhage (ICH) and ischaemic stroke. Randomised controlled trials and non-randomised trials were considered for inclusion. Results: In total, 67 studies were included, and 38 studies were meta-analysed. Participants taking apixaban had significantly lower stroke/SE compared to patients taking VKAs (relative risk (RR) 0.77, 95% confidence interval (CI) 0.64–0.93, I² = 94%) and dabigatran (RR 0.84, 95% CI 0.74–0.95, I² = 66%), but not to patients administered rivaroxaban. There was no statistical difference in mortality between apixaban and VKAs or apixaban and dabigatran. Compared to patients administered rivaroxaban, participants taking apixaban had lower mortality rates (RR 0.83, 95% CI 0.71–0.96, I² = 96%). Apixaban was associated with a significantly lower risk of major bleeding compared to VKAs (RR 0.58, 95% CI 0.52–0.65, I² = 90%), dabigatran (RR 0.79, 95% CI 0.70–0.88, I² = 78%) and rivaroxaban (RR 0.61, 95% CI 0.53–0.70, I² = 87%). Conclusions: Apixaban was associated with a better overall safety and effectiveness profile compared to VKAs and other DOACs.

Comparative Effectiveness and Safety of Low-Dose Oral Anticoagulants in Patients With Atrial Fibrillation

Aims: Observational studies of various dose levels of direct oral anticoagulants (DOACs) for patients with atrial fibrillation (AF) found that a high proportion of patients received a dose lower than the target dose tested in randomized controlled trials. There is a need to compare low-dose DOACs with warfarin or other DOACs on effectiveness and safety. Methods: Using administrative data from Quebec province, Canada, we built a cohort of new warfarin or DOAC users discharged from hospital between 2011 and 2017. We determined CHA₂DS₂-VASc and HAS-BLED scores, and comorbidities for 3-year prior cohort entry. The primary effectiveness endpoint was a composite of ischemic stroke/systemic embolism (SE), and secondary outcomes included a safety composite of major bleeding (MB) events and effectiveness composite (stroke/SE, death) at 1-year follow-up. We contrasted each low-dose DOAC with warfarin or other DOACs as references using inverse probability of treatment weighting to estimate marginal Cox hazard ratios (HRs). Results: The cohort comprised 22,969 patients (mean age: 80-86). We did not find a significant risk reduction for the stroke/SE primary effectiveness endpoint for DOACs vs. warfarin; however, we observed a significantly lower risk for low-dose dabigatran vs. warfarin (HR [95%CI]: 0.59 [0.42-0.81]) for effectiveness composite, mainly due to a lower death rate. The differences in effectiveness and safety composites between low-dose rivaroxaban vs. warfarin were not significant. However, low-dose apixaban had a better safety composite (HR: 0.68 [0.53-0.88]) vs. warfarin. Comparisons of dabigatran vs. apixaban showed a lower risk of stroke/SE (HR: 0.53 [0.30-0.93]) and a 2-fold higher risk of MB. The MB risk was higher for rivaroxaban than for apixaban (HR: 1.58 [1.09-2.29]). Conclusions: The results of this population-based study suggest that low-dose dabigatran has a better effective composite than warfarin. Compared with apixaban, low-dose dabigatran had a better effectiveness composite but a worse safety profile. Low-dose apixaban had a better safety composite than warfarin and other low-dose DOACs. Given that the comparative effectiveness and safety seem to vary from one DOAC to another, pharmacokinetic data for specific populations are now warranted.

Rivaroxaban Is Associated With Higher Rates of Gastrointestinal Bleeding Than Other Direct Oral Anticoagulants : A Nationwide Propensity Score-Weighted Study

BACKGROUND

Gastrointestinal bleeding (GIB) rates for direct oral anticoagulants (DOACs) and warfarin have been extensively compared. However, population-based studies comparing GIB rates among different DOACs are limited.

OBJECTIVE

To compare rates of GIB among apixaban, dabigatran, and rivaroxaban.

DESIGN

Nationwide population-based cohort study.

SETTING

Landspítali-The National University Hospital of Iceland and the 4 regional hospitals in Iceland.

PATIENTS

New users of apixaban, dabigatran, and rivaroxaban from 2014 to 2019.

MEASUREMENTS

Rates of GIB were compared using inverse probability weighting, Kaplan-Meier survival estimates, and Cox regression.

RESULTS

In total, 2157 patients receiving apixaban, 494 patients receiving dabigatran, and 3217 patients receiving rivaroxaban were compared. For all patients, rivaroxaban had higher overall rates of GIB (3.2 vs. 2.5 events per 100 person-years; hazard ratio [HR], 1.42 [95% CI, 1.04 to 1.93]) and major GIB (1.9 vs. 1.4 events per 100 person-years; HR, 1.50 [CI, 1.00 to 2.24]) compared with apixaban. Rivaroxaban also had higher GIB rates than dabigatran, with similar point estimates, although the CIs were wider and included the possibility of a null effect. When only patients with atrial fibrillation were included, rivaroxaban was associated with higher rates of overall GIB than apixaban (HR, 1.40 [CI, 1.01 to 1.94]) or dabigatran (HR, 2.04 [CI, 1.17 to 3.55]). Dabigatran was associated with lower rates of upper GIB than rivaroxaban in both analyses.

LIMITATIONS

Unmeasured confounding and small subgroup analyses.

CONCLUSION

Rivaroxaban was associated with higher GIB rates than apixaban and dabigatran regardless of treatment indication.

PRIMARY FUNDING SOURCE

Icelandic Centre for Research and Landspítali-The National University Hospital of Iceland.

Effectiveness and safety of non-vitamin K antagonist oral anticoagulants in patients with non-valvular atrial fibrillation: A nationwide, population-based study in Korea

BACKGROUND

To compare the risk of stroke/systemic embolism (S/SE) and major bleeding (MB) between non-vitamin K antagonist oral anticoagulants (NOACs) in patients with atrial fibrillation (AF), this retrospective study was conducted using the Korean Health Insurance Review & Assessment Service (HIRA) claims database.

METHODS

Patients with AF who initiated NOACs (apixaban, dabigatran, and rivaroxaban) from July 1, 2015 to November 30, 2016 were included. We applied inverse probability of treatment weighting (IPTW) method using propensity score to make weighted populations having similar characteristics between groups. Hazard ratio (HR) of S/SE and MB were estimated by Cox proportional hazard model.

RESULTS

Of the 39 783 patients with AF, 10 564; 11 418; and 17 801 used apixaban, dabigatran, and rivaroxaban, respectively. The mean CHA2DS2-VASc and HAS-BLED scores were 4.59 ~ 4.69 and 3.58 ~ 3.62, respectively, among all patients after applying IPTW. For S/SE, there were no significant differences between NOACs (HR [95% confidence interval (CI)]): apixaban vs dabigatran (0.99 [0.87-1.13]), apixaban vs rivaroxaban (0.95 [0.84-1.07]), and dabigatran vs rivaroxaban (0.96 [0.85-1.08]). For MB (HR [95% CI]), both apixaban (0.77 [0.68-0.86]) and dabigatran (0.88 [0.79-0.98]) had a significantly lower risk compared with rivaroxaban. Apixaban also had a significantly lower risk of MB compared with dabigatran (0.87 [0.76-0.99]).

CONCLUSIONS

In real-world practice among Korean AF patients with relatively high risk of stroke and bleeding, there were no significant differences in the risk of S/SE between all NOAC comparisons. Apixaban was associated with lower risk of MB than dabigatran and rivaroxaban.

Comparison of the Safety and Effectiveness of Four Direct Oral Anticoagulants in Japanese Patients with Nonvalvular Atrial Fibrillation Using Real-World Data

Direct oral anticoagulants (DOACs) are widely used for the prevention of ischemic stroke and systemic embolism in patients with nonvalvular atrial fibrillation (NVAF). However, the differences in safety and effectiveness among four DOACs, dabigatran, rivaroxaban, apixaban, and edoxaban, in Japanese patients have not been clarified. Therefore, we conducted a retrospective cohort study to directly compare the safety and effectiveness among the four DOACs using the Japan Medical Data Center (JMDC) claims database. We identified 3823 patients with NVAF who started receiving a DOAC between March 2011 and June 2017. The safety outcome was major bleeding (a composite outcome of intracranial, gastrointestinal, respiratory, or renal/urinary tract bleeding) and the effectiveness outcome was the composite of ischemic stroke including transient ischemic attack (TIA) or systemic embolism. We constructed a Cox proportional hazard model to calculate the hazard ratio (HR) for all four DOAC combinations. The risk of major bleeding was significantly lower in the dabigatran group than in the apixaban group (HR, 0.55; 95% confidence interval (CI), 0.31-0.93; p = 0.03). In contrast, there was no significant difference in the risk of major bleeding among the other DOACs. In the composite risk of ischemic stroke including TIA or systemic embolism, there was no significant difference among the four DOACs. This study suggested that in the current use of DOACs in Japanese patients with NVAF, dabigatran had a significantly lower risk of major bleeding than apixaban, but there was no significant difference in effectiveness among the four DOACs.

Joint Latent Class Analysis of Oral Anticoagulation Use and Risk of Stroke or Systemic Thromboembolism in Patients with Atrial Fibrillation

BACKGROUND

Oral anticoagulation (OAC) is recommended to reduce the risk of stroke or systemic thromboembolism (TE) in atrial fibrillation (AF). In this study, we applied novel joint latent class mixed models to identify heterogeneous patterns of trajectories of OAC use and determined how these trajectories are associated with risks of thromboembolic outcomes.

METHODS AND RESULTS

We used 2013-2016 claims data from a 5% random sample of Medicare beneficiaries, obtained from the Centers for Medicare and Medicaid Services. Our study sample included 16,399 patients newly diagnosed with AF in 2014-2015 who were followed for 12 months after the first AF diagnosis and filled at least one OAC prescription in this time period. OAC use was defined as the number of days covered with OACs every 30-day interval after the first AF diagnosis. We used a joint latent class mixed model to simultaneously evaluate the longitudinal patterns of OAC use and time to stroke or TE, while adjusting for age, race, CHAD2S2-VASc score and HAS-BLED score. Five classes of OAC use patterns were identified: late users (17.8%); late initiators (12.5%); early discontinuers (18.6%); late discontinuers (15.4%); and continuous users (35.6%). Compared with continuous users, the risk of stroke or TE was higher for participants in the late initiators (hazard ratio [HR] 1.73, 95% confidence interval [CI] 1.49-2.01) and late discontinuers (HR 1.23, 95% CI 1.04-1.45) classes.

CONCLUSION

Late initiators and late discontinuers had a higher risk of stroke or TE than continuous users. Early initiation and continuous OAC use is important in preventing stroke and TE among patients diagnosed with AF.

Predicting the Risk of Ischemic Stroke in Patients Treated with Novel Oral Anticoagulants: A Machine Learning Approach

INTRODUCTION

The aim of this cohort study was to estimate the predictors of ischemic stroke in patients treated with non-vitamin K antagonist oral anticoagulants (NOACs) in a large database containing data from general practitioners in Germany using machine learning methods.

METHODS

This retrospective cohort study included 39,652 patients with a diagnosis of atrial fibrillation (AF) and an initial prescription of NOAC in 1,278 general practices in Germany between January 2011 and December 2018. Of 39,652 patients, 2,310 (5.8%) receive the first stroke or TIA diagnosis during the follow-up time (average follow-up time 2.5 [SD: 1.8] years). Sub-Population Optimization and Modeling Solutions (SOMS) tool was used to identify subgroups at a higher risk of stroke compared to the overall population receiving NOAC based on 37 different variables.

RESULTS

Using SOMS, a total of 9 variables were considered important for the stroke prediction. Age had 59.1% of prediction importance, following by ischemic heart diseases (10.6%), urinary tract infections (4.6%), dementia (3.5%), and male sex (3.5%). Further variables with less importance were dizziness (2.2%), dorsalgia (1.5%), shoulder lesions (1.1%), and diabetes mellitus (1.1%).

DISCUSSION/CONCLUSIONS

The stroke risk in AF patients treated with NOAC could be predicted based on comorbidities like ischemic heart diseases, urinary tract infections, and dementia additionally to age and male sex. Knowing and addressing these factors may help reduce the risk of stroke in this patient population.

Disparities in Anticoagulant Therapy Initiation for Incident Atrial Fibrillation by Race/Ethnicity Among Patients in the Veterans Health Administration System

IMPORTANCE

Atrial fibrillation is a common cardiac rhythm disturbance causing substantial morbidity and mortality that disproportionately affects racial/ethnic minority groups. Anticoagulation reduces stroke risk in atrial fibrillation, yet studies show it is underprescribed in racial/ethnic minority patients.

OBJECTIVE

To compare initiation of anticoagulant therapy by race/ethnicity for patients in the Veterans Health Administration (VA) system with atrial fibrillation.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included 111 666 patients within the VA system with incident atrial fibrillation between January 1, 2014, and December 31, 2018. Data were analyzed between December 1, 2019, and March 31, 2020.

EXPOSURES

Any anticoagulation was defined as receipt of warfarin or direct-acting oral anticoagulants, apixaban, dabigatran, edoxaban, or rivaroxaban.

MAIN OUTCOMES AND MEASURES

Initiation of any anticoagulation (or direct-acting oral anticoagulant therapy in those who initiated any anticoagulation) was examined within 90 days of an index atrial fibrillation diagnosis.

RESULTS

Our final cohort comprised 111 666 patients (109 386 men [98.0%] and 95 493 White patients [85.5%]; mean [SD] age, 72.9 [10.4] years). A total of 69 590 patients (62.3%) initiated any anticoagulant therapy, varying 10.5 percentage points by race/ethnicity (P < .001); initiation was lowest in Asian (52.2% [n = 676]) and Black (60.3% [n = 6177]) patients and highest in White patients (62.7% [n = 59 881]). Among anticoagulant initiators, 45 381 (65.2%) used direct-acting oral anticoagulants, varying 7.2 percentage points by race/ethnicity (P < .001); initiation was lowest in Hispanic (58.3% [n = 1470]), American Indian/Alaska Native (59.8% [n = 201]), and Black (60.9% [n = 3763]) patients and highest in White patients (66.0% [n = 39 502). Compared with White patients, the odds of initiating any anticoagulant therapy were significantly lower for Asian (adjusted odds ratio [aOR], 0.82; 95% CI, 0.72-0.94) and Black (aOR, 0.90; 95% CI 0.85-0.95) patients. Among initiators, the adjusted odds of direct-acting oral anticoagulant initiation were significantly lower for Hispanic (aOR, 0.79; 95% CI, 0.70-0.89), American Indian/Alaska Native (aOR, 0.75; 95% CI, 0.57-0.99), and Black (aOR, 0.74; 95% CI 0.69-0.80) patients.

CONCLUSIONS AND RELEVANCE

This cohort study found that in patients with incident atrial fibrillation managed in the VA system, race/ethnicity was independently associated with initiating any anticoagulant therapy and direct-acting oral anticoagulant use among anticoagulant initiators. Understanding the reasons for these treatment disparities is essential to improving equitable atrial fibrillation management and outcomes among racial/ethnic minority patients treated in the VA system.

Risk of Severe Abnormal Uterine Bleeding Associated with Rivaroxaban Compared with Apixaban, Dabigatran and Warfarin

INTRODUCTION

There have been reports of clinically relevant uterine bleeding events among women of reproductive age exposed to rivaroxaban.

OBJECTIVE

The aim of this study was to compare the risk of severe abnormal uterine bleeding (SAUB) resulting in transfusion or surgical intervention among women on rivaroxaban versus apixaban, dabigatran and warfarin.

METHODS

We conducted a retrospective cohort study in the FDA's Sentinel System (10/2010-09/2015) among females aged 18+ years with venous thromboembolism (VTE), or atrial flutter/fibrillation (AF) who newly initiated a direct oral anticoagulant (DOAC; rivaroxaban, apixaban, dabigatran) or warfarin. We followed women from dispensing date until the earliest of transfusion or surgery following vaginal bleeding, disenrollment, exposure or study end date, or recorded death. We estimated hazard ratios (HRs) using Cox proportional hazards regression via propensity score stratification. Four pairwise comparisons were conducted for each intervention.

RESULTS

Overall, there was an increased risk of surgical intervention with rivaroxaban when compared with dabigatran (HR 1.19; 95% CI 1.03-1.38), apixaban (1.23; 1.04-1.47), and warfarin (1.34; 1.22-1.47). No difference in risk for surgical intervention was observed for dabigatran-apixaban comparisons. Increased risk of transfusion was observed for rivaroxaban compared with dabigatran (1.49; 1.03-2.17) only. For patients with no gynecological history, rivaroxaban was associated with risk of surgical intervention compared with dabigatran (1.22; 1.05-1.42), apixaban (1.25; 1.04-1.49), and warfarin (1.36; 1.23-1.50).

CONCLUSION

Our study found increased SAUB risk with rivaroxaban use compared with other DOACs or warfarin. Increased risk with rivaroxaban was present among women without underlying gynecological conditions. Women on anticoagulant therapy should be aware of a risk of SAUB.

Phase I clinical trial of an antithrombotic drug protocol combining apixaban and clopidogrel in dogs

INTRODUCTION

Combining an antiplatelet drug, clopidogrel, with the direct oral Factor Xa inhibitor, apixaban, could provide an effective antithrombotic strategy in dogs. Thus, a limited 3 + 3 phase I dose-escalation clinical trial in healthy dogs was conducted to evaluate bleeding (primary end-point) and pharmacodynamic (PD)/pharmacokinetic (PK) parameters (secondary end-point).

ANIMALS

Eleven beagle dogs, median body weight 10.2 kg (9.7-10.9 kg), were enrolled.

METHODS

Four doses of apixaban (three dogs/dose) administered for eight days. Clopidogrel dose was fixed at 18.75 mg per os (PO) q 24 h with escalation of apixaban dose at 5 mg PO q 12 h, 5 mg PO q 8 h, 10 mg PO q 12 h, and 10 mg PO q 8 h. Laboratory testing included fecal occult blood, coagulation parameters, Factor X activity, apixaban concentration, platelet aggregometry, and thromboelastography on days 1, 3, and 8.

RESULTS

Evidence of bleeding was not observed at any dosage. Dose-dependent changes in PD/PK parameters between baseline and 3 h post-medication were observed including a prolongation of prothrombin time, a prolongation of activated partial thromboplastin time, a decrease of Factor X activity level, and increased apixaban concentration.

CONCLUSIONS

The combination of apixaban at a dosage range of approximately 0.5 mg/kg PO q 12 h to 1 mg/kg PO q 8 h and clopidogrel at approximately 1.8 mg/kg PO q 24 h did not cause bleeding over a one-week period in healthy dogs. Clinically relevant changes in PD/PK data occur at all dosage levels. This study provides a starting point for longer-term clinical trials to determine safety and efficacy.

Comparative effectiveness and safety of direct acting oral anticoagulants in nonvalvular atrial fibrillation for stroke prevention: a systematic review and meta-analysis

PURPOSE

To systematically review available evidence of indirect comparisons from RCTs and direct comparisons from observational studies regarding the comparative effectiveness and safety of DOACs in patients with AF.

METHODS

Electronic databases including EMBASE, MEDLINE, and PUBMED were searched up to June 5th, 2020. Primary endpoints included effectiveness (stroke or systemic embolism [SE]) and safety (major bleeding) outcomes. Bucher methods and random-effects models were conducted for indirect and direct comparisons among DOACs, respectively. Ranking probability analyses and the number needed to treat for net effect (NNTnet) were applied.

RESULTS

A total of 36 studies, involving 7 RCTs (n = 60,292 patients) and 29 observational studies (n = 1,164,821 patients), were included for analyses. Regarding the risk of stroke/SE, no significant differences were found from indirect comparisons of RCTs among the DOACs. For major bleeding, apixaban tended to be safer than rivaroxaban and dabigatran based on both direct and indirect comparisons (all p < 0.05; evidence quality: very low to moderate). Ranking probability analysis showed that apixaban had a high probability of being the best treatment in decreased risk of stroke/SE and major bleeding (80.30% and 91.30%, respectively). Likewise, apixaban was found to have the highest net clinical benefit (0.02, 95% CI: 0.014-0.029) and smallest NNTnet (48, 95% CI: 35-74).

CONCLUSIONS

Apixaban appeared to have a favorable effectiveness-safety profile compared with the other DOACs in AF for stroke prevention, based on evidence from both direct and indirect comparisons. However, additional high-quality evidence is needed to support firm recommendations on clinical decision-making.

Antithrombotic Management and Long-Term Outcomes of Patients with Atrial Fibrillation. Insights from CRAFT Trial

Background: We aimed to compare long-term outcomes in Polish patients with atrial fibrillation (AF) according to oral anticoagulation (OAC) type and to evaluate the predictive value of common thromboembolic and bleeding risk scores. Methods: Data from the CRAFT trial (NCT02987062) were included. The primary study endpoint was major adverse event (MAE; all-cause death, thromboembolic and hemorrhagic event) during the mean four-year follow-up period. Results: Out of 2983 patients with available follow-up data, 1686 (56%) were prescribed with vitamin K antagonist (VKA), 891 (30%) with rivaroxaban and 406 (14%) with dabigatran. Predominance of elderly and female patients with previous history of thromboembolic and hemorrhagic events was observed within rivaroxaban (vs. other OAC) group. Higher rate of MAEs and its components was observed in patients on VKA followed by rivaroxaban as compared to patients on dabigatran (43% vs. 42% vs. 31%, p < 0.01). After group matching based on clinical characteristics, higher risk of hemorrhagic events in VKA (vs. dabigatran) and rivaroxaban (vs. dabigatran) group were observed. The available thromboembolic (CHA₂DS₂-VASs, ATRIA, R₂CHADS₂) and bleeding (HAS-BLED, ATRIA, ORBIT) risk scores showed poor prediction value. Conclusions: Despite no difference in the thromboembolic event rate, treatment with VKA and rivaroxaban was associated with a significant increase in the risk of hemorrhagic events.

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.

Critical appraisal and issues regarding generalisability of comparative effectiveness studies of NOACs in atrial fibrillation and their relation to clinical trial data: a systematic review

OBJECTIVE

To critically appraise the published comparative effectiveness studies on non-vitamin K antagonist oral anticoagulants (NOACs) in non-valvular atrial fibrillation (NVAF). Results were compared with expectations formulated on the basis of trial results with specific attention to the patient years in each study.

METHODS

All studies that compared the effectiveness or safety between at least two NOACs in patients with NVAF were eligible. We performed a systematic literature review in Medline and EMbase to investigate the way comparisons between NOACs were made, search date 23 April 2019. Critical appraisal of the studies was done using among others ISPOR Good Research Practices for comparative effectiveness research.

RESULTS

We included 39 studies in which direct comparison between at least two NOACs were made. Almost all studies concerned patient registries, pharmacy or prescription databases and/or health insurance database studies using a cohort design. Corrections for differences in patient characteristics was applied in all but two studies. Eighteen studies matched using propensity scores (PS), 8 studies weighted patients based on the inverse probability of treatment, 1 study used PS stratification and 10 studies applied a proportional hazards model. These studies have some important limitations regarding unmeasured confounders and channelling bias, even though the larger part of the studies were well conducted technically. On the basis of trial results, expected differences are small and a naïve analysis suggests trials with between 7200 and 56 500 patients are needed to confirm the observed differences in bleedings and between 51 800 and 7 994 300 to confirm differences in efficacy.

DISCUSSION

Comparisons regarding effectiveness and safety between NOACs on the basis of observational data, even after correction for baseline characteristics, may not be reliable due to unmeasured confounders, channelling bias and insufficient sample size. These limitations should be kept in mind when results of these studies are used to decide on ranking NOAC treatment options.

Improving the Management of Atrial Fibrillation in General Practice: Protocol for a Mixed Methods Study

BACKGROUND

Atrial fibrillation (AF) is one of the commonest arrhythmias observed in general practice. The thromboembolic complications of AF include transient ischemic attack, stroke, and pulmonary embolism. Early recognition of AF can lead to early intervention with managing the risks of these complications.

OBJECTIVE

The primary aim of this study is to investigate if patients are managed in general practice according to current national guidelines. In addition, the study will evaluate the impact of direct oral anticoagulant use with respect to AF complications in a real-world dataset. The secondary aims of the study are to develop a dashboard that will allow monitoring the management of AF in general practice and evaluate the usability of the dashboard.

METHODS

The study was conducted in 2 phases. The initial phase was a quantitative analysis of routinely collected primary care data from the Oxford Royal College of General Practitioners Research and Surveillance Center (RCGP RSC) sentinel network database. AF cases from 2009 to 2019 were identified. The study investigated the impact of the use of anticoagulants on complications of AF over this time period. We used this dataset to examine how AF was managed in primary care during the last decade. The second phase involved development of an online dashboard for monitoring management of AF in general practice. We conducted a usability evaluation for the dashboard to identify usability issues and performed enhancements to improve usability.

RESULTS

We received funding for both phases in January 2019 and received approval from the RCGP RSC research committee in March 2019. We completed data extraction for phase 1 in May 2019 and completed analysis in December 2019. We completed building the AF dashboard in May 2019. We started recruiting participants for phase 1 in May 2019 and concluded data collection in July 2019. We completed data analysis for phase 2 in October 2019. The results are expected to be published in the second half of 2020. As of October 2020, the publications reporting the results are under review.

CONCLUSIONS

Results of this study will provide an insight into the current trends in management of AF using real-world data from the Oxford RCGP RSC database. We anticipate that the outcomes of this study will be used to guide the development and implementation of an audit-based intervention tool to assist practitioners in identifying and managing AF in primary care.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR1-10.2196/21259.

Nonsteroidal Antiinflammatory Drugs, Anticoagulation, and Upper Gastrointestinal Bleeding

Advanced age, history of peptic ulcer disease, Helicobacter pylori, coadministration of nonsteroidal antiinflammatory drugs (NSAIDs), corticosteroids, anticoagulation, and antiplatelets are risk factors for gastrointestinal bleeding in the elderly. Awareness of these risks and appropriate use of NSAIDs, particularly in those needing antiplatelet or anticoagulant therapy, is critical to optimal management. Careful selection of elderly patients requiring antiplatelet, anticoagulation, or chronic NSAID therapy for cotherapy with proton pump inhibitors can significantly reduce morbidity and mortality from gastrointestinal bleeding.

National Physician Survey for Nonvalvular Atrial Fibrillation (NVAF) Anticoagulation Comparing Knowledge, Attitudes and Practice of Cardiologist to PCPs

Introduction:

NVAF is estimated to affect between 6.4 and 7.4 million Americans in 2018, and increases the risk of stroke 5-fold. To mitigate this risk, guidelines recommend anticoagulating AF patients unless their stroke risk is very low. Despite these recommendations, 30.0-60.0% of NVAF patients do not receive indicated anticoagulation. To better understand why this may be, we surveyed PCPs and cardiologists nationwide on their attitudes, knowledge and practices toward managing NVAF with warfarin and direct-acting oral anticoagulants (DOACs).

Methods:

We surveyed 1,000 PCPs and 500 cardiologists selected randomly from a master list of the American Medical Association, using a paper based, anonymous, self-administered, mailed scannable survey. The survey contained questions on key demographics and data concerning attitudes, knowledge and practices related to prescribing DOACs. The surveys went out in the fall/winter of 2017-8 with a $10 incentive gift card. Survey responses were scanned into an Excel database and analyzed using SAS 9.3 (Cary, NC) for descriptive and inferential statistics.

Results:

Two hundred and forty-nine providers (167 PCPs, 82 cardiologists) participated in the study with a response rate of 18.8% (249/1320). Respondent mean years ±SD of experience since completing residency was 23.2 ± 13.8. Relative to cardiologists, less PCPs use CHADsVASC (36.8% vs. 74.4%) (p < 0.0001); more have never used HAS-BLED, HEMORR2HAGES, or ATRIA (38.5% vs. 9.8%) (p < .0001); more felt that their lack of knowledge/experience with DOACs was a barrier to prescribing the agents (p = 0.005); and more reported that they could use additional education on DOACs (87.0% vs. 47.0%) (p < 0.0001). Overall, cardiologists were more concerned about ischemic stroke outcomes, while PCPs were more concerned with GI bleeding. Cardiologists also felt that clinical trial data were most helpful in choosing the most appropriate DOAC for their patients, while PCPs felt that Real World Data was most useful.

Conclusions:

Cardiologists were more concerned with ischemic stroke while anticoagulating patients and utilized screening instruments like CHADsVASC in a majority of their patients. PCPs were concerned with GI bleeds when anticoagulating but nearly 40.0% utilized no screening tools to assess bleeding risk. Our findings show that future education about DOACs would be warranted especially with PCPs.

What gastroenterologists should know about direct oral anticoagulants

Direct oral anticoagulants are being increasingly used in patients with non-valvular atrial fibrillation and venous thromboembolism, due to their improved efficacy/ safety ratio, a predictable anticoagulant effect without need for routine coagulation monitoring, and fewer food and drug interactions compared with vitamin K antagonists. Gastrointestinal bleeding remains a serious complication, whose management is challenging for gastroenterologists due to the lack of a standardized clinical approach. Clinical experience on periendoscopic management of these drugs is still limited and there is a paucity of clinical data supporting guidelines recommendations', and this ultimately turns out in different, unsubstantiated and potentially harmful practices of patient management. Present study will provide a thorough revision on the risk of GI bleeding for DOAC therapy and the identification of patient risk factors to individualize treatment. Moreover, the approach to management of DOACs in case of bleeding complications is discussed, and an algorithm of different strategies in presence or not of plasma level measurement is proposed. Finally the periendoscopic management for elective procedures will be reviewed, at the light of the guideline recommendations and new evidences from observational studies.

Premature permanent discontinuation of apixaban or warfarin in patients with atrial fibrillation

AIMS

The ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial randomised patients with atrial fibrillation at risk of stroke to apixaban or warfarin. We sought to describe patients from ARISTOTLE who prematurely permanently discontinued study drug.

METHODS/RESULTS

We performed a posthoc analysis of patients from ARISTOTLE who prematurely permanently discontinued study drug during the study or follow-up period. Discontinuation rates and reasons for discontinuation were described. Death, thromboembolism (stroke, transient ischaemic attack, systemic embolism), myocardial infarction and major bleeding rates were stratified by ≤30 days or >30 days after discontinuation. A total of 4063/18 140 (22.4%) patients discontinued study drug at a median of 7.3 (2.2, 15.2) months after randomisation. Patients with discontinuation were more likely to be female and had a higher prevalence of cardiovascular disease, diabetes, renal impairment and anaemia. Premature permanent discontinuation was more common in those randomised to warfarin than apixaban (23.4% vs 21.4%; p=0.002). The most common reasons for discontinuation were patient request (46.1%) and adverse event (34.9%), with no significant difference between treatment groups. The cumulative incidence of clinical events ≤30 days after premature permanent discontinuation for all-cause death, thromboembolism, myocardial infarction, and major bleeding was 5.8%, 2.6%, 0.9%, and 3.0%, respectively. No significant difference was seen between treatment groups with respect to clinical outcomes after discontinuation.

CONCLUSION

Premature permanent discontinuation of study drug in ARISTOTLE was common, less frequent in patients receiving apixaban than warfarin and was followed by high 30-day rates of death, thromboembolism and major bleeding. Initiatives are needed to reduce discontinuation of oral anticoagulation.

The use and adherence of oral anticoagulants in Primary Health Care in Catalunya, Spain: A real-world data cohort study

OBJECTIVE

We aimed to describe sociodemographic, comorbidities, co-medication and risk of thromboembolic events and bleeding in patients with NVAF initiating oral anticoagulants (OAC) for stroke prevention, and to estimate adherence and persistence to OAC.

SETTING

Primary Health Care (PHC) in the Catalan Health Institute (ICS), Catalunya, Spain.

PARTICIPANTS

All NVAF adult patients initiating OAC for stroke prevention in August 2013-December 2015.

METHODS

Population-based cohort study. Persistence was measured in patients initiating OAC in August 2013-December 2014.

DATA SOURCE

SIDIAP, which captures electronic health records from PHC in the (ICS), covering approximately 5.8 million people.

RESULTS

51,690 NVAF patients initiated OAC; 47,197 (91.3%) were naive to OAC and 32,404 (62.7%) initiated acenocoumarol. Mean age was 72.8 years (SD 12.3) and 49.4% were women. Platelet-aggregation inhibitors were taken by 9105 (17.6%) of the patients. Persistence and adherence were estimated up to the end of follow-up. For 22,075 patients, persistence was higher among the non-naive patients [n=258 (61.7%)] than among the naive [n=11,502 (53.1%)]. Adherence was estimated for patients initiating DOAC and it was similar in naive and non-naive patients. Among the naive to DOAC treatment, those starting rivaroxaban showed a highest proportion [(n=360 (80.1%)] of good adherence at implementation (MPR>80%) while patients starting dabigatran were less adherent [n=203 (47.8%)].

CONCLUSIONS

Acenocoumarol was the most frequently prescribed OAC as first therapy in NVAF patients. Non-naive to DOAC showed better persistence than naive. Rivaroxaban showed higher proportion of adherent patients during the implementation phase than apixaban and dabigatran the lowest.

Comparing risk of major bleeding between users of different oral anticoagulants in patients with nonvalvular atrial fibrillation

AIMS

The introduction of direct oral anticoagulants (DOACs) has broadened the treatment arsenal for nonvalvular atrial fibrillation, but observational studies on the benefit-risk balance of DOACs compared to vitamin K antagonists (VKAs) are needed. The aim of this study was to characterize the risk of major bleeding in DOAC users using longitudinal data collected from electronic health care databases from 4 different EU-countries analysed with a common study protocol.

METHODS

A cohort study was conducted among new users (≥18 years) of DOACs or VKAs with nonvalvular atrial fibrillation using data from the UK, Spain, Germany and Denmark. The incidence of major bleeding events (overall and by bleeding site) was compared between current use of DOACs and VKAs. Cox regression analysis was used to calculate hazard ratios and 95% confidence intervals (CI) and adjust for confounders.

RESULTS/CONCLUSION

Overall, 251 719 patients were included across the 4 study cohorts (mean age ~75 years, % females between 41.3 and 54.3%), with overall hazard ratios of major bleeding risk for DOACs vs VKAs ranging between 0.84 (95% CI: 0.79-0.90) in Denmark and 1.13 (95% CI 1.02-1.25) in the UK. When stratifying according to the bleeding site, risk of gastrointestinal bleeding was increased by 48-67% in dabigatran users and 30-50% for rivaroxaban users compared to VKA users in all data sources except Denmark. Compared to VKAs, apixaban was not associated with an increased risk of gastrointestinal bleeding in all data sources and seemed to be associated with the lowest risk of major bleeding events compared to dabigatran and rivaroxaban.

Real-World Direct Comparison of the Effectiveness and Safety of Apixaban, Dabigatran, Rivaroxaban, and Warfarin in Medicare Beneficiaries With Atrial Fibrillation

It remains unknown whether the comparative effectiveness of direct oral anticoagulants (DOACs) and warfarin differs between atrial fibrillation patients with and without a history of stroke or transient ischemic attack (TIA). Using 2012 to 2014 Medicare claims data, we identified patients newly diagnosed with AF in 2013 to 2014 who initiated apixaban, dabigatran, rivaroxaban, or warfarin. We categorized patients based on a history of stroke or TIA. We constructed Cox proportional hazard models that included indicator variables for treatment groups, a history of stroke or TIA, and the interaction between them, and controlled for demographics and clinical characteristics. DOACs were generally more effective than warfarin in stroke prevention; however, there were important differences between subgroups defined by a history of ischemic stroke. In particular, the superiority of dabigatran compared with warfarin in ischemic stroke prevention was more pronounced in patients with a history of stroke or TIA (hazard ratio [HR] 0.64; 95% confidence interval [CI] 0.48 to 0.85) than in patients with no history of stroke or TIA (HR 0.94; 95% CI 0.75 to 1.16; p value for interaction = 0.034). There was no difference in the risk of stroke between apixaban, dabigatran, and rivaroxaban in patients with no history of stroke or TIA. However, in patients with a history of stroke or TIA, the risk of stroke was lower with dabigatran (HR 0.64; 95% CI 0.48 to 0.85) and rivaroxaban (HR 0.70; 95% CI 0.56 to 0.87), compared with apixaban (p value for both interactions <0.05). In conclusion, the comparative effectiveness of DOACs differs substantially between patients with and without a history of stroke or TIA; specifically, apixaban is less effective in patients with a history of stroke or TIA.

Relevance of physicochemical properties and functional pharmacology data to predict the clinical safety profile of direct oral anticoagulants

Direct oral anticoagulants (DOACs) have rapidly become the drug class of choice for anticoagulation therapy in secondary care. It is known that gastrointestinal hemorrhage are potential side effects of the DOAC drug class. In this study we have investigated the relevance of molecular structure and on/off-target pharmacology as a predictor of adverse drug reactions (ADRs) for the DOAC drug class. Use of the Reaxys MedChem module allowed for data mining of all possible reported off-target effects of the DOAC class members. For the first time, the MHRA Yellow card database in combination with prescribing rates in the United Kingdom (data for n = 30 566 936 DOAC Rx (up to 2017) and ADR data n = 22 275 (up to 2018)) were used for our data comparison of DOACs. From the underlying reported data, we were able to rank the DOACs in terms of the likely adverse events we would expect to observe. We identified potential risks of ADRs based on the DOACs pharmacology including the expected GI hemorrhage, but also the unexpected risk of stroke, pulmonary embolism and kidney injury. Statistically significant (P < .001) differences were found between all DOACs and their total number of ADRs. Although the risks are small, strong statistical correlation between observed pharmacology and national ADR data is observed in three out of the five areas of concern.

Non-Vitamin K Antagonist Oral Anticoagulants and the Gastrointestinal Bleeding Risk in Real-World Studies

In the present study, we aimed to provide evidence from high-quality real world studies for a comprehensive and rigorous analysis on the gastrointestinal bleeding (GIB) risk for non-vitamin K antagonist oral anticoagulants (NOACs). We performed a systematic search of MEDLINE, EMBASE and PUBMED, and of 286 records screened, we included data from 11 high-quality real-world studies, coordinated by independent research groups over the last 3 years, that reported major GIB events in patients given NOACs or vitamin K antagonists for patients with nonvalvular atrial fibrillation. The lowest risk of gastrointestinal bleeding was with apixaban compared with warfarin (hazard ratio (HR) for GIB for apixaban ranging between 0.45 (95% confidence interval (CI) 0.34 to 0.59) and 1.13 (95% CI 0.79 to 1.63)). Apixaban was associated with a lower risk of GI bleeding than dabigatran ((HR ranging between 0.39 (95% CI 0.27 to 0.58) and 0.95 (95% CI 0.65 to 1.18)) or rivaroxaban ((HR ranging between 0.33 (95% CI 0.22 to 0.49) and 0.82 (95% CI 0.62 to 1.08)). The results of our study confirm a low or a similar risk for major GIB between patients receiving apixaban or dabigatran compared with warfarin, and apixaban appears to be associated with the lowest risk of GIB.

Adherence to Anticoagulation and Risk of Stroke Among Medicare Beneficiaries Newly Diagnosed with Atrial Fibrillation

INTRODUCTION

The objective of this study was to compare the risk of stroke in atrial fibrillation (AF) with adherent use of oral anticoagulation (OAC), non-adherent use, and non-use of OAC.

METHODS

Using 2013-2016 Medicare claims data, we identified patients newly diagnosed with AF in 2014-2015 and collected prescriptions filled for OAC in the 12 months after AF diagnosis (n = 39,272). We categorized participants each day into three time-dependent exposures: adherent use (≥ 80% of the previous 30 days covered with OAC), non-adherent use (0-80% covered with OAC), and non-use (0%). We constructed Cox proportional hazards models to estimate the association between time-dependent exposures and time to stroke, adjusting for demographics and clinical characteristics.

RESULTS

The sample included 39,272 patients. Study participants spent 35.0% of the follow-up period in the adherent use exposure category, 10.9% in the non-adherent category, and 54.0% in the non-use category. OAC adherent use [hazard ratio (HR) 0.62; 95% confidence interval (CI) 0.52-0.74] and non-adherent use (HR 0.74; 95% CI 0.57-0.95) were associated with lower hazards of stroke than non-use. Adherent use of DOAC (HR 0.54; 95% CI 0.42-0.69) and warfarin (HR 0.70; 95% CI 0.56-0.89) was associated with lower risk of stroke than non-use, but the risk of stroke did not statistically differ between DOAC and warfarin adherent use (HR 0.77; 95% CI 0.56-1.04).

DISCUSSION

Although adherence to OAC reduces stroke risk by nearly 40%, newly diagnosed AF patients in Medicare adhere to OAC on average only one third of the first year after AF diagnosis.

Risk of Major Gastrointestinal Bleeding With New vs Conventional Oral Anticoagulants: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

There is controversy over whether use of non-vitamin K antagonist oral anticoagulants (NOACs) associates with increased risk of major gastrointestinal bleeding (GIB) compared with conventional therapies (such as vitamin K antagonists or anti-platelet agents). We performed a systematic review and meta-analysis of data from randomized controlled trials and high-quality real-world studies.

METHODS

We performed a systematic search of the MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials.gov Website databases (through Oct 12, 2018) for randomized controlled trials and high-quality real-world studies that reported major GIB events in patients given NOACs or conventional therapy. Relative risks (RRs) for randomized controlled trials and adjusted hazard ratios (aHRs) for real-world studies were calculated separately using random-effects models.

RESULTS

We analyzed data from 43 randomized controlled trials (183,752 patients) and 41 real-world studies (1,879,428 patients). The pooled major rates of GIB for patients on NOACs (1.19%) vs conventional treatment (0.92%) did not differ significantly (RR from randomized controlled trials, 1.09; 95% CI, 0.91-1.31 and aHR from real-world studies, 1.02; 95% CI, 0.94-1.10; P_interaction=.52). Rivaroxaban, but not other NOACs, was associated with an increased risk for major GIB (RR from randomized controlled trials, 1.39; 95% CI, 1.17-1.65 and aHR from real-world studies, 1.14; 95% CI, 1.04-1.23; P_interaction = .06). Analyses of subgroups, such as patients with different indications, dosage, or follow-up time, did not significantly affect results. Meta-regression analysis failed to detect any potential confounding to impact the primacy outcome.

CONCLUSIONS

In a systematic review and meta-analysis of data from randomized controlled trials and real-world studies, we confirmed that there is no significant difference in risk of major GIB between patients receiving NOACs vs conventional treatment. Rivaroxaban users had a 39% increase in risk for major GIB.

All-Cause Mortality and Cardiovascular Outcomes With Non-Vitamin K Oral Anticoagulants Versus Warfarin in Patients With Heart Failure in the Food and Drug Administration Adverse Event Reporting System

BACKGROUND

Many patients with heart failure (HF) are treated with warfarin or non-vitamin K oral anticoagulants (NOACs). Randomized outcome-driven comparisons of different anticoagulant strategies in HF are lacking. Data from international, government-mandated registries may be useful in understanding the real-life use of various anticoagulants and how they are linked to outcomes.

STUDY QUESTION

To assess 2015 annual all-cause mortality, myocardial infarction, and stroke rates co-reported for warfarin and NOACs in subjects with and without HF in the US Food and Drug Administration Adverse Event Reporting System (FAERS) database.

STUDY DESIGN

We extracted and examined outcome cases in subjects with HF and on warfarin, dabigatran, rivaroxaban, apixaban, or edoxaban and stratified these according to anticoagulants.

MEASURES AND OUTCOMES

Annual all-cause mortality, myocardial infarction, and stroke in FAERS.

ANALYSIS METHOD

Odds ratio (OR) and χ(Equation is included in full-text article.)for oral anticoagulants from FAERS with and without HF among complete primary reports issued in 2015.

RESULTS

FAERS reported 137,026 HF cases, with death co-reported in 42,942 (31.3%). In total, 11,278 (8.2%) HF patients were treated with anticoagulants, with more prescribed warfarin (n = 8260) than all NOACs combined (n = 3018). Very few reports for edoxaban were available. Warfarin consistently displayed a signal for excess adverse events compared to NOACs: OR (95% confidence interval) for the composite of mortality, myocardial infarction, and stroke were 1.91 (1.76-2.07) versus apixaban, 1.92 (1.81-2.03) versus dabigatran, 4.09 (3.38-4.37) versus rivaroxaban, and 2.64 (2.53-2.76) versus all NOACs combined (all P < 0.001). Warfarin, compared to all NOACs combined, demonstrated higher rates of all-cause mortality [OR = 2.69 (95% confidence interval, 2.49-2.90)], myocardial infarction [5.30 (4.17-6.74)], stroke [OR = 8.85 (6.61-11.84)], and ischemic stroke [OR = 12.73 (8.87-18.27); all P < 0.001].

CONCLUSIONS

Annual 2015 FAERS profiles in HF patients reveal that warfarin was numerically dominant. Warfarin was associated with higher risk of death, myocardial infarction, and stroke compared to NOACs. These observational data provide real-world insight into a potential safety benefit of NOACs over warfarin in the setting of HF.

Persistent Rivaroxaban Effect Due to Impaired Renal Clearance and Medication Effects

Rivaroxaban (Xarelto; Johnson & Johnson Services, Inc) is a direct oral anticoagulant (DOAC) that works by directly inhibiting the active site of factor Xa (FXa). Rivaroxaban is metabolized and cleared via the kidney and liver. The results of various studies have shown that patients with severe renal impairment should receive reduced dosages of rivaroxaban or another anticoagulant due to impaired clearance. Although it is not required, monitoring rivaroxaban is useful in some conditions; however, the assays required for such monitoring are not readily available. Herein, we present a case of a 68-year-old Caucasian male patient who was receiving rivaroxaban (20 mg/day) for atrial flutter and had mild renal impairment. The patient was found to have increased effect of rivaroxaban due to further impairment of renal clearance caused by several renally cleared medications. This case highlights the importance of closely examining the renal function of and medication list for a patient before starting DOACs such as rivaroxaban.