Direct anticoagulant drugs to overcome limitations of vitamin K antagonists. A critical appraisal of data in atrial fibrillation patients

Direct Oral Anticoagulants in Special Patient Populations

Anticoagulants are a cornerstone of treatment in atrial fibrillation. Nowadays, direct oral anticoagulants (DOACs) are extensively used for this condition in developed countries. However, DOAC treatment may be inappropriate in certain patient populations, such as: patients with chronic kidney disease in whom DOAC concentrations may be dangerously elevated; frail elderly patients with an increased risk of falls; patients with significant drug-drug interactions (DDI) affecting either DOAC concentration or effect; patients at the extremes of body mass in whom an "abnormal" volume of distribution may result in inappropriate drug concentrations; patients with recurrent stroke reflecting an unusually high thromboembolic tendency; and, lastly, patients who experience major hemorrhage on an anticoagulant and in whom continued anticoagulation is deemed necessary. Herein we provide a fictional case-based approach to review the recommendations for the use of DOACs in these special patient populations.

Apixaban and Rivaroxaban Anti-Xa Concentration Utilization in Clinical Practice

ABSTRACT

Drug-specific anti-Xa concentrations can be used to assess the presence of drug effects; however, there is inadequate guidance for clinicians on the interpretation and clinical application of these results. The purpose of this study is to review patients' first apixaban and rivaroxaban anti-Xa concentrations to identify indications for monitoring and common therapeutic interventions made based on the results. In addition, we compared bleeding and thrombotic outcomes between the obesity group body mass index ≥40 kg/m 2 and the standard group body mass index 25-39.9 kg/m 2 . A retrospective analysis was conducted at a large academic medical center from January 1, 2020, to December 31, 2020. Primary outcomes were indications for anti-Xa concentrations and interventions on results. A total of 180 patients were included in the analysis, with 119 patients (66%) in the apixaban group and 61 patients (34%) in the rivaroxaban group. The most common indications for anti-Xa concentrations were extreme body weight (23%) and concern for bleeding (22%). About half of the anti-Xa concentrations resulted in therapy changes including holding for procedure, switching to heparin or enoxaparin, holding for an elevated anti-Xa concentration or concern for bleeding, adjusting direct-acting oral anticoagulant dose, or switching to an alternative oral anticoagulant. There were no differences in bleeding complications (5% [2] vs. 16% [14], P = 0.11) or thrombotic complications (8% [3] vs. 9% [8], P = 0.85) between the obesity group and the standard group. Despite the lack of validation of therapeutic ranges for anti-Xa concentrations, this study showed clinical situations where anti-Xa concentration monitoring can be of value.

Safety and efficacy of direct oral anticoagulants in comparison with warfarin across different BMI ranges: A systematic review and meta-analysis

Background

Many publications have compared various outcomes defining safety and efficacy of DOACs across different BMI ranges. Our meta-analysis compares warfarin and DOACs for its treatment effects over different BMI ranges.

Methods

A systematic search was conducted from inception to May 2021 on PubMed, Scopus and Embase databases. The data was extracted and pooled using a random effects model. Our study consisted of patients being treated for VTE and AF, across different BMI categories. For the comparison of DOAC, risk ratios (RR) with 95% confidence intervals (CIs) were used, whilst for the second comparison between warfarin and DOACs odds ratios (OR) were used.

Results

In our first comparison, 12 studies (n = 254,908 patients) were included. For our second comparison, six studies (n = 109,609 patients) were included. Major bleeding events in the underweight group were higher than normal weight [RR: 1.89 (1.10, 3.23); P = 0.02; I² = 0%]. Overweight patients were related with reduced rates of VTE than in patients with normal BMI [RR: 0.86 (0.76, 0.97); P = 0.02; I² = 0%]. In comparison with patients receiving warfarin, DOACs had significantly reduced risk of major bleeding in normal weight, overweight and obese [OR: 0.64 (0.49, 0.83); P = 0.0007 I² = 90%].

Conclusion

The risk of VTE reduces with an increasing BMI, hence there could be a possible obesity paradox in patients with anticoagulation therapy. In comparison to warfarin, DOACs proved to be the safer option by having a reduced risk of bleeding across all BMI categories.

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Warfarin therapy and its effectiveness for prevention of thromboembolism.

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Effect of warfarin and DOACs over different BMI ranges.

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Safety and efficacy of DOACs across different BMI ranges.

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Lower risk of bleeding in normal weight, overweight, and obese patients with DOACs.

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Warfarin and DOACs across different BMI categories in VTE and AF patients.

Current status and factors influencing oral anticoagulant therapy among patients with non-valvular atrial fibrillation in Jiangsu province, China: a multi-center, cross-sectional study

Background

It has been reported that oral anticoagulation (OAC) is underused among Chinese patients with non-valvular atrial fibrillation (NVAF). Non-vitamin K antagonist oral anticoagulants (NOAC) have been recommended by recent guidelines and have been covered since 2017 by the Chinese medical insurance; thus, the overall situation of anticoagulant therapy may change. The aim of this study was to explore the current status of anticoagulant therapy among Chinese patients with NVAF in Jiangsu province.

Methods

This was a multi-center, cross-sectional study that was conducted in seven hospitals from January to September in 2017. The demographic characteristics and medical history of the patients were collected by questionnaire and from the medical records. Multivariate logistic regression was used to identify factors associated with anticoagulant therapy.

Results

A total of 593 patients were included in the analysis. A total of 35.6% of the participants received OAC (11.1% NOAC and 24.5% warfarin). Of those patients with a high risk of stroke, 11.1% were on NOAC, 24.8% on warfarin, 30.6% on aspirin, and 33.6% were not on medication. Self-paying, duration of AF ≥5 years were negatively associated with anticoagulant therapy in all patients (OR 1.724, 95% CI 1.086~2.794; OR 1.471, 95% CI 1.006~2.149, respectively), whereas, permanent AF was positively associated with anticoagulant therapy (OR 0.424, 95% CI 0.215~0.839). Among patients with high risk of stroke, self-paying and increasing age were negatively associated with anticoagulant therapy (OR 2.305, 95% CI 1.186~4.478; OR 1.087, 95% CI 1.041~1.135, respectively).

Conclusions

Anticoagulant therapy is positively associated with permanent AF and negatively associated with self-paying, duration of AF > 5 years. Furthermore, the current status of anticoagulant therapy among Chinese patients with NVAF in Jiangsu province does not appear optimistic. Therefore, further studies should focus on how to improve the rate of OAC use among NVAF patients. In addition, policy makers should pay attention to the economic situation of the patients with NVAF using NOAC.

Trial registration

2,017,029. Registered 20 March 2017 (retrospectively registered).

Anticoagulant therapies and outcomes in obese patients with acute venous thromboembolism

BACKGROUND

Direct oral anticoagulants (DOACs) are recommended in preference to traditional anticoagulants (LMWH ± warfarin) for treating acute venous thromboembolism (VTE). However, guidelines suggest avoiding DOACs in those >120 kg given limited data.

OBJECTIVE

To capture outcome and prescription fill data in a cohort of patients >120 kg with acute VTE out to 1 year.

METHODS

Using linked administrative data, a retrospective sub-study of obese patients (>120 kg) with acute VTE discharged from institutions from 2014 to 2017 was performed. Primarily, the overall rate of recurrent VTE was assessed. Secondarily, anticoagulant regimens (agent/dosing) and bleeding events were recorded with recurrent events confirmed by chart reviews. Outcomes were compared between DOACs and traditional therapies.

RESULTS

Amongst 187 patients included, the overall rate of recurrent VTE out to 1 year was 0.006 events/patient year, and the only event during the entire follow-up occurred off therapy. Throughout the year, 38.5% were prescribed a DOAC only, 32.6% were prescribed traditional therapy only and 23.5% were switched from LMWH/warfarin to a DOAC. The proportion of patients receiving sub-therapeutic, standard or supra-therapeutic regimens were: DOAC (11.1%, 85.2%, 3.7%), LMWH (24.2%, 71.0%, 4.8%), warfarin (30.4%, 55.0%, 15.0%). Bleeding occurred in 9 (8.3%) and 9 (11.5%) patients on DOAC and traditional therapy, respectively (relative risk 0.85 [95%CI 0.44-1.28]).

CONCLUSIONS

More obese patients with acute VTE were prescribed DOACs than traditional therapies. Standard dosing was used for DOACs (85.2%), whereas sub-optimal dosing occurred for 25-33% receiving traditional therapies. Rates of recurrent VTE and bleeding were similar in the two groups, lending support for DOAC use in this population.

Jurisdictional Guidance on DOAC Use-Will It Affect Practice? A Comparison of European, American, and Canadian Product Monographs

Objective: To identify clinically relevant areas of concordance and discordance between product monographs for 4 direct oral anticoagulants (DOACs) approved by regulatory authorities in Europe, the United States, and Canada. Data Sources: For each DOAC (apixaban, dabigatran, edoxaban, rivaroxaban), manufacturer product monographs were retrieved from the European Medicines Database, US Food and Drug Administration, and Health Canada Drug Product Database. Data Extraction: Monographs for each DOAC were independently reviewed by 2 investigators to identify areas of concordance and discordance. Discordance existed if it was deemed that a potentially clinically relevant difference existed. A heat map summarizing the data was created to identify areas of complete concordance, partial concordance (concordance between 2 of 3 monographs), and complete discordance. Data Synthesis: The areas of concordance were indications for use, use in extremes of weight, and switching to/from the DOAC. Areas of discordance included the following: differing recommendations for use/dosing with renal dysfunction; contraindication or use with caution with drug interactions, pregnancy, and hepatic/renal dysfunction; and timing of DOAC with spinal/epidural anesthesia after a procedure or traumatic puncture. Relevance to Patient Care and Clinical Practice: Concordance was most evident for uncomplicated patients with atrial fibrillation or venous thromboembolism, whereas discordance emerged for those having characteristics/factors wherein clinicians may seek clarification within product monographs (eg, impaired renal/hepatic function, drug interactions). As such, clinicians must be familiar with product information within their country of practice. Conclusion: Variability between jurisdictions was evident, and variability of DOAC use is likely to increase with expanding worldwide uptake.

Predictors of new oral anticoagulant drug initiation as opposed to warfarin in elderly adults: a retrospective observational study in Southern Italy

AIM

The aim of this study was to assess the predictive role of age, gender, and number and type of co-treatments for new oral anticoagulant (NOAC) vs warfarin prescription in elderly patients naïve for the aforementioned drugs.

MATERIALS AND METHODS

Data collected in the period from January 1, 2014, to December 31, 2014, in Caserta Local Health Unit administrative databases (Campania Region, Italy) were screened to identify new users of oral anticoagulants (OACs) who were 75 years or older and whose OAC prescriptions amounted to >90 days of treatment. Age, gender, and number and type of concomitant medications at the time of first OAC dispensation were retrieved. Multivariable logistic regression analysis was used to assess the role of the aforementioned predictors for NOAC initiation as opposed to warfarin.

RESULTS

Overall, 2,132 incident users of OAC were identified, of whom 967 met all inclusion criteria. In all, 490 subjects (50.7%) received an NOAC and 477 (49.3%) received warfarin. Age >75 years was positively associated with lower odds of NOAC initiation (OR: 0.969, 95% CI: 0.941-0.998, P=0.038). Similarly, multiple concomitant medication was negatively associated with NOAC initiation compared to warfarin (OR [five to nine drugs] group: 0.607, 95% CI: 0.432-0.852, P=0.004; OR [ten+ drugs] group: 0.372, 95% CI: 0.244-0.567, P<0.001). Prior exposure to platelet aggregation inhibitor drugs was associated with the initiation of NOACs (OR: 3.474, 95% CI: 2.610-4.625).

CONCLUSION

Age and multiple co-medication were negatively associated with NOAC initiation.

The involvement of pharmacies in the screening of undiagnosed atrial fibrillation

Early identification of atrial fibrillation (AF) is now a priority in cardiovascular prevention because AF is common although often asymptomatic, and is associated with poor outcomes that are highly preventable with appropriate medical treatment. In Italy, AF prevalence among subjects aged ≥65 years ranges from 5 to 6% in observational studies based on the diagnosis recorded by general practitioners to 10-11% in studies where ECG screening is routinely offered. It is thus evident that a large number of subjects are not detected by conventional approach, and new strategies are required to increase early detection of AF. In particular, the changing position of pharmacies in the health system should be considered. Because of its small geographical size, insular nature and captive population, the Isle of Elba represents an ideal setting to test new strategies for stroke reduction. The Elba-FA project was thus designed to determine the feasibility and impact of the combined involvement of pharmacies and general practices to screen undiagnosed AF, with the ultimate aim of reducing the burden of stroke and arterial thromboembolism. The findings obtained with this approach might have broad implications for cardiovascular prevention at the general population level in Italy.

The risk of gastrointestinal bleeding in patients receiving dabigatran etexilate: a systematic review and meta-analysis of the literature

BACKGROUND

Evidence on the risk of gastrointestinal (GI) bleeding associated with dabigatran etexilate (DE) is contrasting. We performed a meta-analysis of literature to address this issue.

METHODS AND RESULTS

Studies on GI bleeding risk in patients receiving DE or vitamin-K antagonists (VKA) were systematically searched. Twenty-three studies (26 datasets) showed no difference in the GI bleeding risk between the 250,871 patients treated with DE and the 460,386 receiving VKA (OR: 1.052, 95% CI: 0.815, 1.359). Similar results were obtained when pooling together adjusted ORs/HRs, obtained by means of multivariate analysis (OR: 1.06, 95% CI: 0.914, 1.222). Compared with VKA, DE use was associated with a significantly lower risk of upper GI (OR: 0.742, 95% CI: 0.569, 0.968), but not of lower GI bleedings (OR: 1.208, 95% CI: 0.902, 1.619). Furthermore, no significant difference in the GI bleeding risk was found when data on DE 110 mg and DE 150 mg twice-daily were separately compared with VKA.

CONCLUSIONS

No difference in GI bleeding risk was found between DE and VKA. These results were confirmed for both dosages of DE and when specifically analyzing lower GI bleeding. In contrast, the risk of upper GI bleeding was lower with DE than with VKA. KEY MESSAGES No difference in the risk of gastrointestinal (GI) bleeding can be found between dabigatran etexilate (DE) and vitamin K-antagonists (VKA). These results are confirmed for both dosages of DE. The risk of upper GI bleeding is lower with DE than with VKA.

Adherence to oral anticoagulant therapy in patients with atrial fibrillation. Focus on non-vitamin K antagonist oral anticoagulants

Oral anticoagulation is pivotal in the management of thromboembolic risk in non-valvular atrial fibrillation (NVAF) patients. Effective anticoagulation is important to avoid major adverse events and medication adherence is central to achieve good anticoagulation control. Non-vitamin K antagonist oral anticoagulants (NOACs) are as effective and safe as vitamin K antagonist (VKAs) in NVAF patients. Due to the absence of routine anticoagulation monitoring with NOACs treatment, concerns have been raised about patient's adherence to NOACs and real-life data demonstrates variability in adherence and persistence. A multi-level approach, including patients' preferences, factors determining physicians' prescribing habits and healthcare system infrastructure and support, is warranted to improve initiation and adherence of anticoagulants. Adherence to NOACs is paramount to achieve a clinical benefit. Implementation of educational programs and easy-to-use tools to identify patients most likely to be non-adherent to NOACs, are central issues in improving the quality of NVAF anticoagulation management.

Efficacy and safety of direct oral anticoagulants in patients undergoing cardioversion for atrial fibrillation: A systematic review and meta-analysis of the literature

BACKGROUND

DOACs are increasingly used in patients with NVAF. Information on efficacy and safety of these compounds in patients undergoing electrical or pharmacological cardioversion is limited. Thus, we performed a systematic review and a meta-analysis of the literature to address this issue.

METHODS

Randomized controlled trials comparing the efficacy and safety of DOACs and VKAs in patients with NVAF were systematically searched in Medline, Web of Science, Scopus, Cochrane, and EMBASE databases (up to September 2014). Pooled relative risk (RR) and the corresponding 95% confidence interval (CI) were calculated for each outcome.

RESULTS

Four randomized controlled trials (3635 patients), for a total of 4517 cardioversions (2869 with DOACs and 1648 with VKAs), were included in the analysis. DOACs and VKAs appeared equally effective in the prevention of stroke/systemic embolism (0.41% vs 0.61%; RR: 0.73, 95% CI: 0.31, 1.72; P=0.48) and of post-cardiovascular death (0.52% vs 0.81%; RR: 0.73, 95% CI: 0.27, 2.03; P=0.55), with a similar risk of major bleeding complications (0.81% vs 0.60%; RR: 1.23, 95% CI: 0.55, 2.71). Heterogeneity among studies was generally absent. Furthermore, the Weighted Mean Incidence (WMI) of complications appeared very low in patients randomized to DOACs (WMI: 0.6% and 0.9% for stroke/systemic embolism and major bleeding, respectively).

CONCLUSION

Our results suggest that DOACs are at least as effective and safe as VKAs in patients with NVAF undergoing to an electrical or pharmacological cardioversion. Thus, DOACs may be considered a valid and practical alternative to VKAs.

Effect of body weight on efficacy and safety of direct oral anticoagulants in the treatment of patients with acute venous thromboembolism: a meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the effect of body weight (BW) on safety and efficacy of direct oral anticoagulants (DOACs).

METHODS

We performed a meta-analysis of randomized controlled trials (RCTs) comparing DOACs with vitamin K antagonists (VKA) in patients with venous thromboembolism (VTE). Efficacy (prevention of recurrent VTE or VTE-related death) and safety (occurrence of major or clinically relevant non-major bleeding) outcomes were stratified according to patients' BW (low, normal, and high).

RESULTS

Six RCTs with a total of 27,023 patients were included. DOACs showed a similar efficacy to VKA in patients with high BW, normal BW, and low BW (RR 0.98, 95% CI 0.72, 1.35; RR 0.91, 95% CI 0.75, 1.09; and RR 0.84, 95% CI 0.57, 1.24, respectively). Safety was comparable among DOACs and VKA in patients with high BW and low BW (RR 0.93, 95% CI 0.65, 1.32; and RR 0.80, 95% CI 0.54, 1.20), whereas DOACs were marginally safer than VKA in normal-BW subjects (RR 0.82, 95% CI 0.67, 1.00). However, the difference among DOACs and VKA in the rate of bleeding episodes appeared similar in the three BW groups.

CONCLUSIONS

Results of our meta-analysis suggested that DOACs might be a safe and effective therapeutic option for the treatment of acute VTE even in the patients with extreme body weights. However, other studies with larger study populations are warranted to confirm our findings.

The clinical impact of different coagulometers on patient outcomes

Introduction

Long-term anticoagulation therapy using vitamin K antagonists (VKA) is used in millions of patients worldwide to reduce the risk of thrombotic or thromboembolic events. Control and monitoring of VKA therapy is improved by the regular self-measurement of international normalized ratio (INR) using a home monitoring device. This retrospective analysis of a large cohort of patients in the Netherlands seeks to determine whether the choice of INR monitor could have a clinical impact on patient outcomes.

Methods

The National Thrombosis Service provides medical supervision, training and support to anticoagulant patients eligible for home-monitoring of INR in the Netherlands. Two INR monitors (CoaguChek XS and INRatio2) have been distributed at random to patients since June 2011, and patient self-testing data (INR measurements and other clinical parameters) have been recorded to measure and improve treatment outcomes. The data have been retrospectively analyzed to determine any effect of the choice of monitor. Univariate and multivariate statistical tests are used to assess any differences between groups in terms of efficacy and safety parameters.

Results

Data from 4,326 patients were collated, and 156,507 INR values were included in the analysis. Over half the patients (54.3%) were being treated for atrial fibrillation, and 77.6% were prescribed acenocoumarol. There were few differences between the patient populations using the two different monitors. Anticoagulant control overall was good, with high percentage of time (87.9%) in the appropriate INR range and low incidence of excessively high or low INR values (0.085/month). Minor clinical events related to safety were low (0.78 per patient-year) and showed few differences between monitors. Mortality rates were similar [hazard ratio (HR) 1.05, 95% confidence interval (CI) 0.65–1.70].

Conclusion

Self-testing data from a large cohort of patients in the Netherlands suggest that there is no clinically relevant effect of the choice of coagulation monitor (CoaguChek XS or INRatio2) on the time in therapeutic range (TTR), minor or fatal outcomes of long-term anticoagulation management.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-014-0124-x) contains supplementary material, which is available to authorized users.