The Dose of Direct Oral Anticoagulants and Stroke Severity in Patients with Acute Ischemic Stroke and Nonvalvular Atrial Fibrillation

Effectiveness and Safety of Reduced and Standard Daily Doses of Direct Oral Anticoagulants in Patients with Nonvalvular Atrial Fibrillation: A Cohort Study Using National Database Representing the Japanese Population

Purpose

To compare the effectiveness and safety of reduced or standard daily doses of direct oral anticoagulants (DOACs) with warfarin in Japanese patients with nonvalvular atrial fibrillation (NVAF). We used post-hoc analyses to identify patient groups that could benefit from reduced-dose DOACs.

Patients and Methods

Using the National Database of Health Insurance Claims and Specific Health Checkups of Japan, we identified 944,776 patients with NVAF who had started an oral anticoagulant after at least one year of non-use between April 2011 and March 2016. We matched patients taking any, reduced, or standard doses of DOACs 1:1 with those taking warfarin. We measured treatment effectiveness based on admission due to stroke or systemic embolism (S/SE) and safety based on admission due to any bleeding (defined as major bleeding, MB). We compared both outcomes between DOACs and warfarin using the Cox proportional hazards model. We used post-hoc analysis to match patients receiving reduced-dose DOACs to those receiving standard-dose DOACs and compared treatment effectiveness and safety.

Results

More than half of patients receiving DOACs used a reduced dose. The occurrences of S/SE and MB in patients receiving any, reduced, or standard doses of DOACs were equal to or lower than those receiving warfarin. In the post-hoc analysis, the risk of S/SE and MB was similar between reduced and standard doses of DOACs except for those with a history of cerebral infarction and CHA2DS2-VASc score ≥3, where the risk of S/SE was lower for reduced doses of any and individual DOACs.

Conclusion

Findings from the current study are consistent with recent Asian and global studies but different from most studies conducted in North America and Europe, where patients receiving a reduced dose of DOACs had an increased risk of S/SE. Future studies should test the reproducibility of results from the current study.

Underdosed Direct Oral Anticoagulants in Atrial Fibrillation Patients Reduce Stroke Severity and Improve Outcome

BACKGROUND AND PURPOSE

Anticoagulant drugs, including vitamin K antagonist (VKA) and direct oral anticoagulants (DOACs), can reduce stroke severity and are associated with good functional outcomes. Some patients are prescribed lower-than-recommended doses of DOACs; whether these have similar effects has not been clarified.

METHODS

We retrospectively evaluated 1,139 consecutive ischemic stroke and transient ischemic attack patients with atrial fibrillation. Patients were divided into 5 groups according to their preceding anticoagulant drug therapies: no anticoagulant therapy (ACn), undercontrolling VKA doses (VKAuc), recommended, controlling VKA doses (VKArec), prescribed underdoses of DOAC (DOACud), and recommended doses of DOAC (DOACrec). We investigated the associations between these anticoagulant drug therapies and patients' initial stroke severity and 3-month outcomes.

RESULTS

Median National Institutes of Health Stroke Scale scores at admission were as follows: ACn: 16, VKAuc: 15, VKArec: 9, DOACud: 5, and DOACrec: 7. When the ACn group was used as a reference, regression analysis showed that VKArec (odds ratio [OR] 1.49, 95% confidence interval [CI] 1.01-2.21), DOACud (OR 2.84, 95% CI: 1.47-5.66), and DOACrec (OR 1.83, 95% CI: 1.23-2.74) were associated with milder stroke severity, while VKAuc was not. Median 3-month modified Rankin Scale scores were 2 in the DOACud and DOACrec groups and 4 in all other groups. After adjusting for confounding factors, DOACud (OR 3.14, 95% CI: 1.50-6.57) and DOACrec (OR 1.67, 95% CI: 1.05-2.64) were associated with good 3-month outcomes while VKAuc and VKArec were not.

CONCLUSIONS

In patients with atrial fibrillation, recommended doses and underdoses of DOACs reduced stroke severity on admission and were associated with good 3-month outcomes.

Preceding direct oral anticoagulant administration reduces the severity of stroke in patients with atrial fibrillation - K-PLUS registry

BACKGROUND

Stroke severity can be mitigated by preceding anticoagulant administration in acute ischemic stroke patients with atrial fibrillation (AF). We investigated if such mitigative effects are different between warfarin and direct oral anticoagulants (DOACs).

MATERIAL AND METHODS

We collected data from a regional multicenter stroke registry. Ischemic stroke or transient ischemic attack patients with AF were included. Background characteristics, National Institutes of Health Stroke Scale (NIHSS) score on admission, lesion characteristics, and in-hospital death were analyzed according to preceding antithrombotic agents at onset.

RESULTS

A total of 2173 patients had AF; 628 were prescribed warfarin, 272 DOACs, 429 antiplatelets alone, and 844 no antithrombotics. The NIHSS score on admission was lowest in the DOACs group compared to the other groups. In neuroimaging analysis, small ischemic lesions were observed more frequently in the DOACs group, while large ischemic lesions were less frequent in this group. When the no antithrombotics group was used as a reference, the adjusted odds ratio for moderate to severe stroke was 0.56 (95% confidence interval, 0.40-0.78) in the DOACs group, while it was 0.98 (0.77-1.24) in the warfarin group and 0.94 (0.72-1.22) in the antiplatelets group. In-hospital mortality was lowest in the DOACs group compared to the other groups.

CONCLUSION

Preceding DOAC administration might mitigate the severity of stroke in AF patients more strongly than other antithrombotics, possibly leading to a better outcome in patients with stroke.

Inappropriate direct oral anticoagulant prescriptions in patients with non-valvular atrial fibrillation: cross-sectional analysis of the French CACAO cohort study in primary care

Background

Direct oral anticoagulants (DOACs) account for an increasing proportion of prescriptions in patients with non-valvular atrial fibrillation (NVAF) in primary care. Inappropriate dosing of DOACs is a common problem, with under-dosing being a particular issue. However, conflicting results have been reported about the factors independently associated with inappropriate dosing.

Aim

To describe inappropriate prescriptions of DOACs among patients in the CACAO French nationwide general practice cohort, and to identify the factors independently associated with inappropriate DOAC doses.

Design and setting

Cross-sectional baseline analysis of the CACAO French national multicentre prospective cohort of adult patients in primary care receiving an oral anticoagulant who were recruited between April and October 2014.

Method

A total of 1111 patients from the CACAO cohort who received a DOAC for NVAF were included in this study. Inappropriate prescriptions of DOACs were described (inappropriate dosage, contraindications, non-indications, interactions, and non-compliance with the precautions for use). Multivariate logistic models were used to investigate factors associated with inappropriate DOAC dosing (under-dosing and over-dosing).

Results

Overall, 438 patients (39.4%) received at least one inappropriate DOAC prescription. The most common inappropriate prescription was inappropriate dosage (n = 374, 33.7%), particularly under-dosing (n = 348, 31.3%). Multivariate analysis revealed that factors independently associated with under-dosing were older age, prescription of apixaban or dabigatran, and a CHA2DS2-VASc score ≥2 vs. a score = 1. Factors with over-dosing were kidney failure, a HAS-BLED score ≥3, and older age.

Conclusion

The appropriateness of DOAC prescribing for NVAF can be improved, especially in older patients, and in patients with kidney failure, a higher risk of ischaemic stroke, and/or a higher risk of bleeding. GPs have a key role in increasing the proportion of appropriate DOAC prescriptions via informational, educational, and/or management strategies.

Clinical Discussions in Antithrombotic Therapy Management in Patients With Atrial Fibrillation: A Delphi Consensus Panel

Background

In recent years, direct-acting oral anticoagulants (DOACs) have entered clinical practice for stroke prevention in non-valvular atrial fibrillation or prevention and treatment of venous thromboembolism. However, remaining uncertainty regarding DOAC use in some clinical scenarios commonly encountered in the real world has not been fully explored in clinical trials.

Methods

We report on use of a Delphi consensus process on DOAC use in non-valvular atrial fibrillation patients. The consensus process dealt with 9 main topics: (i) DOACs vs vitamin K antagonists in atrial fibrillation (AF) patients; (ii) therapeutic options for patients with stable total time in range treated with vitamin K antagonists; (iii) therapeutic options for patients aged > 85 years; (iv) therapeutic management of hyperfiltering patients; (v) pharmacologic interactions; (vi) therapeutic options in the long-term treatment (prevention) of patients with AF and acute coronary syndrome after the triple therapy; (vii) low doses of DOACs in AF patients; (viii) ischemic stroke in patients inappropriately treated with low doses of DOACs; (ix) management of patients taking DOACs with left atrial appendage thrombosis.

Results

A total of 101 physicians (cardiologists, internists, geriatricians, and hematologists) from Italy expressed their level of agreement on each statement by using a 5-point Likert scale (1 = strongly disagree; 2 = disagree; 3 = somewhat agree; 4 = agree; 5 = strongly agree). Votes 1-2 were considered to be disagreement; votes 3-5 were considered to be agreement. Agreement among the respondents of ≥ 66% for each statement was considered consensus. A brief discussion of the results for each topic is also reported.

Conclusions

In clinical practice, there is still uncertainty on DOAC use, especially in elderly, fragile, comorbid, and hyperfiltering patients.

Clinical presentation, diagnostic findings and management of cerebral ischemic events in patients on treatment with non-vitamin K antagonist oral anticoagulants - A systematic review

Background

Non-vitamin K antagonist oral anticoagulants (NOAC) are equally or potentially superior in terms of effectiveness in the prevention of ischemic stroke and carry a lower associated risk of intracranial hemorrhage compared to Vitamin K antagonists. Nevertheless, ischemic strokes also occur in patients who are being treated with NOAC. In those particular patients, knowledge about the underlying stroke etiology, clinical presentation, acute management, and complication rates is scarce.

Objective

Systematic literature review to provide a comprehensive clinical overview in terms of presentation, laboratory, imaging parameters and outcomes of patients suffering from acute cerebral ischemic events (i.e. TIA and acute ischemic stroke) while on treatment with a NOAC. Only if available, comparison to VKA is presented which was not the primary focus of this analysis.

Data sources

PubMed/MEDLINE, Scopus and EMBASE from January 1, 2006, to November 20, 2018.

Study eligibility criteria

52 studies providing detailed information on a total of 12247 patients were included. We excluded case reports and case series with less than five patients.

Study appraisal and synthesis method

We systematically assessed study quality using a bias tool and pooled consistent data.

Results

Existing data indicates milder stroke severity and smaller infarct size of acute ischemic stroke on treatment with NOAC compared to stroke occurrence on Vitamin K antagonists (VKA). Established risk factors for ischemic events also play a role in stroke while on NOACs, albeit the underlying etiology remains poorly understood. Intravenous thrombolysis and endovascular therapy seem to be safe and effective, but patient selection for recanalization therapies is challenging.

Limitations

Limited quality of published data, duplicate cases, statistical issues of data pooling, possible incomplete retrieval of identified research and reporting bias might have limited our findings.

Conclusions

Acute ischemic events despite treatment with NOAC therapy are insufficiently investigated.

Systematic review registration number

PROSPERO: CRD42018074853.

Clinical Outcomes of Off-Label Dosing of Direct Oral Anticoagulant Therapy Among Japanese Patients With Atrial Fibrillation Identified From the SAKURA AF Registry

BACKGROUND

Off-label dosing of direct oral anticoagulants (DOACs) is encountered clinically among patients with atrial fibrillation (AF), although data on the clinical outcomes of over- and under-dosing are lacking in Japan. Methods and Results: We examined the clinical outcomes of off-label DOAC dosing using the SAKURA AF Registry, a prospective multicenter registry in Japan. Among 3,237 enrollees, 1,676 under any of the 4 DOAC regimens were followed up for a median of 39.3 months: 746 (45.0%), appropriate standard-dose; 477 (28.7%), appropriate low-dose; 66 (4.0%), over-dose; and 369 (22.2%) under-dose. Compared with the standard-dose group, patients in the under- and over-dose groups were significantly older and had a higher stroke risk. After multivariate adjustment, stroke/systemic embolism (SE) and death events were equivalent between the standard- and under-dose groups, but major bleeding events tended to be lower in the under-dose group (hazard ratio [HR] 0.474, P=0.0739). Composite events (stroke/SE, major bleeding, or death) were higher in the over-dose than in the standard-dose group (HR 2.714, P=0.0081).

CONCLUSIONS

Clinical outcomes were not worse for under-dose than for standard-dose users among patients with different backgrounds. Over-dose users, however, were at higher risk for all clinical events and required careful follow-up. Further studies are needed to clarify the safety and effectiveness of off-label DOAC dosing in Japan.

The dose of direct oral anticoagulants and outcomes of intracerebral hemorrhage: Preliminary findings

OBJECTIVES

The effect of a direct-acting oral anticoagulant (DOAC) dose on intracerebral hemorrhage (ICH) severity and outcome remains unclear. The aim of this study is to clarify the frequency of off-label dosing of DOAC treatments in ICH patients and compare clinical characteristics.

PATIENTS AND METHODS

We studied 43 patients with ICH who were treated with DOAC for nonvalvular atrial fibrillation before the onset of ICH. DOAC treatments were categorized into three groups based on the following doses: optimal dose, under-dose, and overdose.

RESULTS

Overall, 31 patients were optimally dosed, 10 were under-dosed, and 2 were overdosed. CHADS₂ and CHA₂DS₂-VASc scores were the highest in the overdose group (median, 4, 6, respectively) and the lowest in the optimal dose group (median, 2, 4, respectively) (p = 0.006, p = 0.005, respectively). ICH severity measured using the National Institutes of Health Stroke Scale scores was the highest in the overdose group (median, 26.5) and the lowest in the under-dose group (median, 6.5) (p = 0.244). Larger initial hematoma volume was observed in the overdose group. The ratio of good outcome (modified Rankin Scale score ≤ 2) was higher in the under-dose group (40%) than the other groups, but this difference was not significant.

CONCLUSION

Our study shows only a few patients received overdosing of a DOAC before the onset of ICH, and they were associated with poorer functional outcomes. Conversely, under-dosing was associated with better functional outcomes than the other groups.