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Is clopidogrel better than aspirin following breakthrough strokes while on aspirin? A retrospective cohort study
Meng Lee1, Yi-Ling Wu1, Jeffrey L Saver2
1Department of Neurology, Chang Gung University College of Medicine, Chang Gung Memorial Hospital, Chiayi Branch, Puzi, Taiwan.
Insights
For patients experiencing ischemic stroke while on aspirin, switching to clopidogrel significantly reduced recurrent vascular events compared to continuing aspirin. Clopidogrel offers better protection against major adverse cardiovascular events and stroke recurrence.
Area of Science:
- Neurology
- Cardiology
- Pharmacology
Background:
- Optimal antiplatelet therapy post-stroke requires further evidence.
- Aspirin is commonly used, but its efficacy in preventing recurrent events in specific patient groups is debated.
Purpose of the Study:
- To compare the effectiveness of clopidogrel versus aspirin reinitiation for vascular risk reduction.
- To evaluate outcomes in patients with ischemic stroke who were already on aspirin.
Main Methods:
- Retrospective nationwide cohort study using Taiwan National Health Insurance Research Database (2003-2009).
- Included 1884 patients with ischemic stroke on aspirin, comparing those switched to clopidogrel versus those continuing aspirin.
- Primary endpoint: hospitalization for major adverse cardiovascular events (MACE); secondary endpoint: recurrent stroke.
Main Results:
- Clopidogrel use was associated with a 46% reduction in MACE (HR=0.54, p<0.001) and recurrent stroke (HR=0.54, p<0.001) compared to aspirin.
- Number needed to treat for MACE was 8, and for recurrent stroke was 9.
Conclusions:
- Clopidogrel initiation is associated with significantly fewer recurrent vascular events in ischemic stroke patients previously treated with aspirin.
- Findings suggest clopidogrel may be a more effective antiplatelet strategy in this population.
Objective:
There is insufficient evidence on which to base a recommendation for optimal antiplatelet therapy following a stroke while on aspirin. The objective was to compare clopidogrel initiation vs aspirin reinitiation for vascular risk reduction among patients with ischaemic stroke on aspirin at the time of their index stroke.
Design:
Retrospective.
Setting:
We conducted a nationwide cohort study by retrieving all hospitalised patients (≥18 years) with a primary diagnosis of ischaemic stroke between 2003 and 2009 from Taiwan National Health Insurance Research Database.
Participants:
Among 3862 patients receiving aspirin before the index ischaemic stroke and receiving either aspirin or clopidogrel after index stroke during follow-up period, 1623 were excluded due to a medication possession ratio <80%. Also, 355 were excluded due to history of atrial fibrillation, valvular heart disease or coagulopathy. Therefore, 1884 patients were included in our final analysis.
Interventions:
Patients were categorised into two groups based on whether clopidogrel or aspirin was prescribed during the follow-up period. Follow-up was from time of the index stroke to admission for recurrent stroke or myocardial infarction, death or the end of 2010.
Primary And Secondary Outcome Measures:
The primary end point was hospitalisation due to a new-onset major adverse cardiovascular event (MACE: composite of any stroke or myocardial infarction). The leading secondary end point was any recurrent stroke.
Results:
Compared to aspirin, clopidogrel was associated with a lower occurrence of future MACE (HR=0.54, 95% CI 0.43 to 0.68, p<0.001, number needed to treat: 8) and recurrent stroke (HR=0.54, 95% CI 0.42 to 0.69, p<0.001, number needed to treat: 9) after adjustment of relevant covariates.
Conclusions:
Among patients with an ischaemic stroke while taking aspirin, clopidogrel initiation was associated with fewer recurrent vascular events than aspirin reinitiation.
