What is the clinical evidence from this study?

Study design: Cohort. Population: Atrial fibrillation detected after stroke (AFDAS) (n=4508). Intervention: Oral anticoagulants (OAC) vs. No oral anticoagulants (Non-OAC). Primary outcome: Ischemic stroke recurrence (aHR 0.84, 95% CI 0.70-0.99, p=0.042).

July 22, 2022Open Access

Oral anticoagulant decreases stroke recurrence in patients with atrial fibrillation detected after stroke

JHJin‐Yi HsuTzu Chi Foundation PLPeter Pin‐Sung LiuTzu Chi Foundation LSLuciano A. SposatoElectrophysiology

Key Result

Oral anticoagulant use in patients with atrial fibrillation detected after stroke was associated with a 16% lower risk of ischemic stroke recurrence (aHR 0.84) compared to non-use.

Study Design

Type

Cohort (n=4,508)

Structured PICO

Does oral anticoagulant use reduce ischemic stroke recurrence in patients with atrial fibrillation detected after stroke?

Population

4,508 adult patients hospitalized with a first-ever ischemic stroke and newly detected atrial fibrillation within 30 days, followed for a median of 2.76 years.

Exposure

Oral anticoagulants (NOAC or warfarin) prescribed within 30 days following the index stroke date

Comparator

No oral anticoagulants received during the 30-day period following the index stroke date

Outcome

Ischemic stroke recurrencehard clinical

In patients with atrial fibrillation detected after stroke, oral anticoagulant use is associated with a reduced risk of ischemic stroke recurrence and death without increasing intracranial hemorrhage.

Main Result

Hazard Ratio: 0.84 (95% CI 0.7–0.99)

Absolute Event Rate: 4.29% vs 5.33%

p-value: p=0.042

Limitations

Diagnosis of AFDAS was mainly based on admission ECGs and 24-h Holter monitoring, limiting generalizability to patients with AFDAS detected on prolonged monitoring.
Use of a limited 30-day time window to identify OAC and non-OAC cohorts may have allowed for treatment crossovers.
Potential unmeasured confounders such as hemorrhagic transformation, size of cerebral infarctions, and cerebral microbleeds.
Higher proportion of severe stroke in the non-OAC group despite inverse probability of treatment weighting.
Use of a 10-year lookback period to exclude previous stroke or AF may have led to misclassification.
Excluding patients re-admitted within the first 30 days may have caused selection bias.
No cut-off value for AF duration was applied to determine clinical relevance.

Abstract

Background: Atrial fibrillation detected after stroke (AFDAS) has a lower risk of ischemic stroke recurrence than known atrial fibrillation (KAF). While the benefit of oral anticoagulants (OAC) for preventing ischemic stroke recurrence in KAF is well established, their role in patients with AFDAS is more controversial. This study aimed to evaluate the association between OAC use and the risk of recurrent ischemic stroke in patients with AFDAS in a real-world setting. Methods: This nationwide retrospective cohort study was conducted using the Taiwan National Health Insurance Research Database. Patients hospitalized with a first-ever ischemic stroke and AFDAS confirmed within 30 days after hospitalization were assigned to OAC and non-OAC cohorts. Inverse probability of treatment weighting was applied to balance the baseline characteristics of the cohorts. The primary outcome was ischemic stroke recurrence. Secondary outcomes were intracranial hemorrhage (ICH), death, and the composite outcome of "ischemic stroke recurrence, ICH, or death." Multivariate Cox proportional hazard models were used to estimate adjusted hazard ratios (aHR) and 95% confidence intervals (CI). Results: A total of 4,508 hospitalized patients with stroke and AFDAS were identified. Based on OAC use, 2,856 and 1,652 patients were assigned to the OAC and non-OAC groups, respectively. During the follow-up period (median duration, 2.76 years), the OAC cohort exhibited a lower risk of ischemic stroke recurrence (aHR, 0.84; 95% CI, 0.70-0.99), death (aHR, 0.65; 95% CI, 0.58-0.73), and composite outcome (aHR, 0.70; 95% CI, 0.63-0.78) than did the non-OAC cohort. The risk of ICH (aHR, 0.96; 95% CI, 0.62-1.50) was not significantly different between the two cohorts. Conclusion: OAC use in patients with AFDAS was associated with reduced risk of ischemic stroke recurrence, without an increased risk of ICH. This supports current guidelines recommending OACs for secondary stroke prevention in patients with AF, regardless of the time of diagnosis.

Ask AI

Helpful

Bookmark

View Full Paper