Stroke prevention with direct oral anticoagulants in high risk elderly atrial fibrillation patients at increased bleeding risk

The optimal antithrombotic strategy for post-stroke patients with atrial fibrillation and extracranial artery stenosis-a nationwide cohort study

BACKGROUND

In post-stroke atrial fibrillation (AF) patients who have indications for both oral anticoagulant (OAC) and antiplatelet agent (AP), e.g., those with carotid artery stenosis, there is debate over the best antithrombotic strategy. We aimed to compare the risks of ischemic stroke, composite of ischemic stroke/major bleeding and composite of ischemic stroke/intracranial hemorrhage (ICH) between different antithrombotic strategies.

METHODS

This study included post-stroke AF patients with and without extracranial artery stenosis (ECAS) (n = 6390 and 28,093, respectively) identified from the Taiwan National Health Insurance Research Database. Risks of clinical outcomes and net clinical benefit (NCB) with different antithrombotic strategies were compared to AP alone.

RESULTS

The risk of recurrent ischemic stroke was higher for patients with ECAS than those without (12.72%/yr versus 10.60/yr; adjusted hazard ratio [aHR] 1.104, 95% confidence interval [CI] 1.052-1.158, p < 0.001). For patients with ECAS, when compared to AP only, non-vitamin K antagonist oral anticoagulant (NOAC) monotherapy was associated with lower risks for ischaemic stroke (aHR 0.551, 95% CI 0.454-0.669), the composite of ischaemic stroke/major bleeding (aHR 0.626, 95% CI 0.529-0.741) and the composite of ischaemic stroke/ICH (aHR 0.577, 95% CI 0.478-0.697), with non-significant difference for major bleeding and ICH. When compared to AP only, warfarin monotherapy was associated with higher risks of major bleeding (aHR 1.521, 95% CI 1.231-1.880), ICH (aHR 2.045, 95% CI 1.329-3.148), and the composite of ischaemic stroke and major bleeding. With combination of AP plus warfarin, there was an increase in ischaemic stroke, major bleeding, and the composite outcomes, when compared to AP only. NOAC monotherapy was the only approach associated with a positive NCB, while all other options (warfarin, combination of AP-OAC) were associated with negative NCB.

CONCLUSIONS

For post-stroke AF patients with ECAS, NOAC monotherapy was associated with lower risks of adverse outcomes and a positive NCB. Combination of AP with NOAC or warfarin did not offer any benefit, but more bleeding especially with AP-warfarin combination therapy.

Risk of Incident Atrial Fibrillation and Subsequent Use of Oral Anticoagulants in Patients with Dementia

BACKGROUND

 Dementia and atrial fibrillation (AF) have many shared risk factors. Besides, patients with dementia are under-represented in randomized trials, and even if AF is present, oral anticoagulants (OACs) are not prescribed frequently. This study aimed to report the incidence of newly diagnosed AF in dementia patients, and the impacts of use of vitamin K antagonist (VKA; e.g., warfarin) and non-VKA OAC (NOACs) on stroke and bleeding outcomes.

METHODS

 Our study utilized the Taiwan National Health Insurance Research Database. A total of 554,074 patients with dementia were compared with 554,074 age- and sex-matched patients without dementia regarding the risk of incident AF. Among patients with dementia who experienced incident AF, the risks of clinical events of patients treated with warfarin or NOACs were compared with those without OACs (reference group).

RESULTS

 The risk of incident AF was greater for patients with dementia compared with those without (adjusted hazard ratio [aHR]: 1.054; 95% confidence interval [CI]: 1.040-1.068 for all types of dementia, aHR: 1.035; 95% CI: 1.020-1.051 for presenile/senile dementia, and aHR: 1.125; 95% CI: 1.091-1.159 for vascular dementia). Among patients with dementia and experienced incident AF, warfarin use was associated with a higher risk of ischemic stroke (aHR: 1.290; 95% CI: 1.156-1.440), intracranial hemorrhage (ICH; aHR: 1.678; 95% CI: 1.346-2.090), and major bleeding (aHR: 1.192; 95% CI: 1.073-1.323) compared with non-OACs. NOAC use was associated with a lower risk of ischemic stroke (aHR: 0.421; 95% CI: 0.352-0.503) and composite risk of ischemic stroke or major bleeding (aHR: 0.544; 95% CI: 0.487-0.608) compared with non-OACs. These results were consistent among the patients after the propensity matching.

CONCLUSION

 In this large nationwide cohort, the risk of newly diagnosed AF was higher in patients with dementia (all dementia, presenile/senile dementia, and vascular dementia) compared with those without dementia. For patients with dementia who experienced incident AF, NOAC use was associated with a better clinical outcome compared with non-OAC. Patients with dementia require a holistic approach to their care and management, including the use of NOACs to reduce the risks of clinical events.

Net Clinical Benefit of Oral Anticoagulation Among Frail Patients With Atrial Fibrillation: Nationwide Cohort Study

BACKGROUND

Frail people with atrial fibrillation are often undertreated with oral anticoagulants (OACs), and evidence for the net clinical benefit (NCB) of OAC is sparse. We, therefore, examined the risk of thromboembolic events, major bleeding, and NCB of anticoagulation treatment.

METHODS

This was a nationwide cohort study including frail patients aged with incident atrial fibrillation between 2013 and 2018. Patients were categorized according to OAC treatment exposure. One-year risks of thromboembolic events and major bleeding were ascertained where death was treated as a competing risk. The NCB of anticoagulation was assessed by a bivariate trade-off between thromboembolism and bleeding.

RESULTS

We identified 36 223 frail patients with atrial fibrillation (median age, 79 years; 50.5% female), of whom 61.8% started OAC therapy, while 38.2% were untreated despite indication for stroke prevention. At 1 year, the risk of thromboembolic events was 2.1% (95% CI, 1.8%-2.3%) among patients not receiving OAC versus 1.5% (95% CI, 1.4%-1.7%) in patients with OAC. The bleeding risk was 3.2% (95% CI, 2.9%-3.5%) among patients without OAC versus 3.5% (95% CI, 3.2%-3.8%) among anticoagulated patients. The NCB was 0.70% (95% CI, 0.32%-1.08%), suggesting a benefit of OAC treatment; however, the NCB declined with age and increasing frailty and was lowest among patients >75 years of age or with high frailty level.

CONCLUSIONS

Frail patients with atrial fibrillation are often untreated with OAC in routine clinical care despite an indication for stroke prevention. The NCB balancing thromboembolic events and major bleeding was in favor of anticoagulation but decreased with advancing age and increasing frailty.

Clinical outcomes in elderly atrial fibrillation patients at increased bleeding risk treated with very low dose vs. regular-dose non-vitamin K antagonist oral anticoagulants: a nationwide cohort study

AIMS

The Edoxaban Low-Dose for Elder Care Atrial Fibrillation Patients (ELDERCARE-AF) trial showed that edoxaban at a very low dosage (VLD) of 15 mg/day was more effective than a placebo at preventing stroke/systemic embolism without significantly increasing the risk of serious bleeding. We aimed to compare the effectiveness and safety for VLD non-vitamin K antagonist oral anticoagulants (NOACs) [edoxaban 15 mg o.d., dabigatran 110 or 150 o.d., apixaban 2.5 mg o.d., or rivaroxaban 10 mg (without the diagnosis of chronic kidney disease) or <10 mg o.d.] vs. regular-dosage (RD) NOACs (edoxaban 60/30 mg o.d. or other labeling-dosage NOACs) among a real-world cohort of elderly atrial fibrillation (AF) population similar to the ELDERCARE-AF cohort.

METHODS AND RESULTS

In this nationwide retrospective cohort study from Taiwan National Health Insurance Research Database (NHIRD), we identified a total of 7294 and 4151 consecutive AF patients aged 80 years or older with a CHADS2 (congestive heart failure, hypertension, age 75 years or older, diabetes mellitus, previous stroke/transient ischemic attack (2 points) score ≥2 who met the enrollment criteria (generally similar to ELDERCARE-AF) taking VLD and RD NOACs from 1 June 2012 to 31 December 2019, respectively. Propensity-score stabilized weighting (PSSW) was used to balance covariates across study groups. Patients were followed up from the first date of prescription for NOACs until the first occurrence of any study outcome, death, or until the end date of the study period (31 December 2020). After PSSW, VLD NOAC was associated with a comparable risk of ischemic stroke/systemic embolism and major bleeding but a higher risk of major adverse limb events (MALEs) requiring lower limb revascularization or amputation [hazard ratio (HR): 1.54, 95% confidential interval (CI): 1.09-2.18; P = 0.014), venous thrombosis (HR: 3.75, 95% CI: 1.56-8.97; P = 0.003), and all-cause mortality (HR: 1.21, 95% CI: 1.15-1.29; P <0.001) compared with RD NOACs. VLD NOACs showed worse outcomes in most net clinical outcome (NCO) benefits. The main result was consistent based on on-treatment analysis or accounting for death as a competing risk. In general, the advantage of NCOs for the RD NOACs over VLD NOACs persisted in most high-risk subgroups, consistent with the main analysis (P for interaction > 0.05).

CONCLUSION

Use of VLD NOACs was associated with a greater risk of arterial and venous thrombosis, death as well as the composite outcomes, when compared with that of RD NOAC in high-risk elderly AF patients at increased bleeding risk. Thromboprophylaxis with RD NOAC is still preferable over VLD NOAC for the majority of elderly AF patients at increased bleeding risk.

Reduced-Dose Rivaroxaban Is Associated with Lower All-Cause Mortality in Older Patients with Nonvalvular Atrial Fibrillation

BACKGROUND

Reduced-dose rivaroxaban (10 mg) was used in the J-ROCKET AF trial, demonstrating safety in the Asian population. It remains unclear whether treatment with reduced-dose versus full-dose rivaroxaban (20 mg/15 mg) is associated with all-cause mortality in older patients with nonvalvular atrial fibrillation. Proposed: To evaluate the effects of reduced-dose rivaroxaban on all-cause mortality in patients over 85.

METHODS

We retrospectively enrolled medical records representing the period from October 2012 to November 2016. The 2 × 2 factorial design incorporated age (≥85 vs. <85) and rivaroxaban use (reduced vs. full dose). The primary study outcomes were all-cause and cardiac-related mortality.

RESULTS

The study enrolled 2386 patients with a mean age of 76.6 ± 10.4 years; 51.8% were male. In the ≥85 group (n = 593), the reduced-dose subgroup had lower all-cause (5.3% vs. 10.6%, p = 0.02) and cardiac-related mortality (1.9% vs. 5.1%, p = 0.04), whereas the younger patients receiving reduced-dose rivaroxaban had higher all-cause mortality (3.7% vs. 1.8%, p = 0.01) but no difference in cardiac-related mortality (1.2% vs. 0.7%, p = 0.33). The rate of hospitalization for heart failure was significantly lower in the elderly group with reduced-dose rivaroxaban (7.2% vs. 15.7%, p < 0.01) but not in the younger group. After adjusting for confounders in the older group, treatment with reduced-dose rivaroxaban was associated with lower risk of all-cause mortality (adjusted HR (aHR): 0.40, 95% CI: 0.21-0.74, p < 0.01) and hospitalization for heart failure (aHR: 0.54, 95% CI: 0.29-0.99, p = 0.05). No associations were found between rivaroxaban dose and cardiac-related mortality in either group, nor between younger age and any outcome.

CONCLUSIONS

Reduced-dose rivaroxaban was associated with lower risks of all-cause mortality and hospitalization for heart failure in older patients with nonvalvular atrial fibrillation. Future studies can investigate the effect of reduced-dose rivaroxaban on prognoses in elderly individuals ≥85 years in the west.

Non-vitamin K antagonist oral anticoagulants in atrial fibrillation patients without previous oral anticoagulants or stable under warfarin: a nationwide cohort study

AIMS

Investigations on non-VKA oral anticoagulants (NOACs) for atrial fibrillation (AF) patients without taking any oral anticoagulants (OACs) or staying well on warfarin were limited. We aimed to investigate the associations between stroke prevention strategies and clinical outcomes among AF patients who were previously well without taking any OACs or stayed well on warfarin for years.

METHODS AND RESULTS

The retrospective analysis included a total of 54 803 AF patients who did not experience an ischaemic stroke or intra-cranial haemorrhage (ICH) for years after AF was diagnosed. Among these patients, 32 917 patients who did not receive OACs were defined as the 'original non-OAC cohort' (group 1), and 8007 patients who continuously received warfarin were defined as the 'original warfarin cohort' (group 2). In group 1, compared to non-OAC, warfarin showed no significant difference in ischaemic stroke (aHR 0.979, 95%CI 0.863-1.110, P = 0.137) while those initiated NOACs were associated with lower risk (aHR 0.867, 95%CI 0.786-0.956, P = 0.043). When compared to warfarin, the composite of 'ischaemic stroke or ICH' and 'ischaemic stroke or major bleeding' was significantly lower in the NOAC initiator with an aHR of 0.927 (95%CI 0.865-0.994; P = 0.042) and 0.912 (95%CI 0.837-0.994; P < 0.001), respectively. In group 2, when compared to warfarin, those shifted to NOACs were associated with a lower risk of ischaemic stroke (aHR 0.886, 95%CI 0.790-0.993, P = 0.002) and major bleeding (aHR 0.849, 95%CI 0.756-0.953, P < 0.001).

CONCLUSIONS

The NOACs should be considered for AF patients who were previously well without taking OACs and those who were free of ischaemic stroke and ICH under warfarin for years.

Risk of Ischemic Bowel Disease in Patients With Atrial Fibrillation Receiving Warfarin or Non-vitamin K Antagonist Oral Anticoagulants

Background

Although atrial fibrillation (AF) is a risk factor for ischemic bowel disease, data regarding the incidence of ischemic bowel disease in patients with anticoagulated AF were limited.

Methods

The present study used the Taiwan NHIRD and included newly diagnosed patients with AF aged ≥ 20 years without ischemic bowel disease from 2012 to 2018. A total of 69,549 patients taking warfarin or non-vitamin K antagonist oral anticoagulants (NOACs) constituted the final study group. We aimed to study the incidence of ischemic bowel disease in patients with AF receiving warfarin or NOACs. Secondary endpoints were also analyzed, including ischemic stroke, systemic embolism, myocardial infarction, mortality, intracranial hemorrhage (ICH), major bleeding, and composite adverse events (ischemic bowel disease or ICH or major bleeding).

Results

There were 43,787 patients taking NOACs and 25,762 patients taking warfarin. The overall incidence rate of ischemic bowel disease was 0.036% per year and increased with the CHA2DS2-VASc scores [0.013% for patients with a CHA2DS2-VASc score of 0 (men) or 1 (women), 0.022% for those with a CHA2DS2-VASc score of 1 (men) or 2 (women), and 0.039% for those with a CHA2DS2-VASc score ≥ 2 (men) or ≥ 3 (women)]. The risk of ischemic bowel disease was similar between NOAC and warfarin groups (0.036%/year vs. 0.037%/year; adjusted hazard ratio 0.802, p = 0.430), whereas the NOAC group had a significantly lower risk of secondary endpoints compared to the warfarin group.

Conclusion

We reported the incidence of ischemic bowel disease in patients with anticoagulated AF from a nationwide cohort database and observed a positive correlation between the increase of CHA2DS2-VASc scores and the incidence rate. Moreover, NOAC was as effective as warfarin for the risk of ischemic bowel disease.