What is the risk of stroke in patients taking anticoagulants (blood thinners) such as warfarin, aspirin, apixaban (Eliquis), or rivaroxaban (Xarelto)?

Stroke Risk While Taking Anticoagulants

The risk of stroke while on anticoagulants varies by agent and indication, but for atrial fibrillation patients, modern direct oral anticoagulants (DOACs) reduce stroke risk to approximately 0.7-1.3% per year, while warfarin carries a 1.3-1.9% annual stroke risk, and aspirin alone results in 3-4% annual stroke risk. 1

Stroke Risk by Anticoagulant Type

Direct Oral Anticoagulants (DOACs)

Apixaban (Eliquis) demonstrates the lowest stroke rates among anticoagulants:

• Annual stroke or systemic embolism rate: 1.27% in atrial fibrillation patients 1
• Ischemic stroke specifically: 0.97% per year 1
• In real-world studies, apixaban shows a 23% reduction in thromboembolic events compared to warfarin 2
• For patients with subclinical atrial fibrillation and prior stroke/TIA, apixaban reduces stroke risk to 1.20% annually versus 3.14% with aspirin 3

Rivaroxaban (Xarelto) shows comparable but slightly higher rates:

• Annual stroke or systemic embolism rate: 1.7-2.1% in atrial fibrillation patients 1
• In head-to-head comparisons with apixaban, rivaroxaban carries a 43% higher stroke risk 4

Dabigatran (Pradaxa) at 150 mg twice daily:

• Annual stroke or systemic embolism rate: 1.11% 1
• Represents a 34% reduction compared to warfarin 1

Warfarin

• Annual stroke rate with therapeutic INR (2.0-3.0): 1.3-1.9% 1
• Critical caveat: Stroke risk increases dramatically with subtherapeutic anticoagulation—patients with INR <2.0 have 1.9 times higher odds of severe stroke compared to INR ≥2.0 5
• INR control quality matters significantly: poor INR control (time in therapeutic range <66%) substantially increases stroke risk 1

Aspirin

• Annual stroke rate: 3.0-3.7% in atrial fibrillation patients 1, 3
• Provides only 19% relative risk reduction compared to no treatment 1
• Should not be used as an alternative to oral anticoagulation for stroke prevention in atrial fibrillation 1

Key Clinical Context

Breakthrough Strokes on Anticoagulation

When stroke occurs despite anticoagulation, the approach depends on the agent:

For patients on dabigatran with recurrent stroke:

• Switch to another DOAC (apixaban, rivaroxaban, or edoxaban) 6
• Evaluate adherence and drug interactions before switching 6

For patients on other DOACs or warfarin:

• Do not routinely switch between DOACs without clear indication—this has no proven efficacy 1
• Switching from warfarin to a DOAC may provide benefit for future stroke prevention 1
• Adding antiplatelet therapy to anticoagulation is not recommended and increases bleeding risk without reducing stroke 1

Hemorrhagic Stroke Risk Trade-off

All anticoagulants increase hemorrhagic stroke risk, but DOACs are substantially safer:

• Apixaban: 0.24% annual intracranial hemorrhage rate 1
• Rivaroxaban: 0.30-0.45% annual intracranial hemorrhage rate 1
• Dabigatran 150mg: 0.30% annual intracranial hemorrhage rate 1
• Warfarin: 0.47-0.74% annual intracranial hemorrhage rate 1

This represents a 48-52% reduction in intracranial hemorrhage with DOACs versus warfarin 1

Special Populations

Patients with prior stroke/TIA:

• Have higher baseline stroke risk but derive greater absolute benefit from anticoagulation 3
• Apixaban in subclinical AF with prior stroke: 7% absolute risk reduction over 3.5 years 3
• Without prior stroke: only 1% absolute risk reduction 3

Patients with valvular heart disease:

• Apixaban shows 43% lower stroke risk compared to rivaroxaban in this population 4
• Absolute risk reduction: 1.1% within one year 4

Common Pitfalls

Subtherapeutic anticoagulation with warfarin is a critical failure point—INR 1.5-1.9 carries similar mortality to INR <1.5 (18% vs 15% at 30 days post-stroke) 5. The full protective effect requires INR ≥2.0 5.

Premature discontinuation of any anticoagulant dramatically increases stroke risk, particularly during transitions between agents 7. When stopping rivaroxaban, coverage with another anticoagulant should be considered unless pathological bleeding is present 7.

Combining antiplatelet agents with anticoagulation without specific indication (such as acute coronary syndrome) increases bleeding without reducing stroke and should be avoided 1, 8.