January 27, 2004Open Access
View Full PaperBenefit of Clopidogrel Over Aspirin Is Amplified in Patients With a History of Ischemic Events
Key Result
In patients with prior symptomatic atherosclerotic disease, clopidogrel reduced the 3-year rate of ischemic stroke, MI, or vascular death compared to aspirin (20.4% vs 23.8%; ARR 3.4%, P=0.045).
Study Design
Type
RCT
Structured PICO
Does clopidogrel reduce the composite of ischemic stroke, myocardial infarction, or vascular death compared to aspirin in patients with a history of symptomatic atherosclerotic disease?
P
Population
Patients from the CAPRIE trial with a history of prior symptomatic atherosclerotic disease (ischemic stroke or myocardial infarction), followed for 3 years.
I
Intervention
Clopidogrel
C
Comparator
Aspirin (acetylsalicylic acid, ASA)
O
Outcome
Composite of ischemic stroke, myocardial infarction, or vascular deathcomposite
In patients with a history of symptomatic atherosclerotic disease, clopidogrel provides an amplified absolute risk reduction for subsequent ischemic events compared to aspirin.
Main Result
Absolute Risk Reduction: 3.4 (95% CI -0.2–7)
Absolute Event Rate: 20.4% vs 23.8%
Absolute Risk Reduction: 3.4%
Number Needed to Treat: 29
p-value: p=0.045
Abstract
BACKGROUND AND PURPOSE: The goal of this study was to examine the influence of preexisting symptomatic atherosclerotic disease on subsequent ischemic event rates and compare the efficacy of clopidogrel versus aspirin (acetylsalicylic acid, ASA) in patients with such disease. METHODS: Using the CAPRIE database, we performed multivariate analyses for patients who had symptomatic atherosclerotic disease (ischemic stroke IS or myocardial infarction MI) in their medical history before enrollment in the Clopidogrel Versus Aspirin in Patients at Risk of Ischemic Events (CAPRIE) trial. Two composite end points were used: (1) IS, MI, or vascular death and (2) IS, MI, or rehospitalization for ischemia. RESULTS: In the CAPRIE population, prior IS and MI each were statistically significant predictors of subsequent ischemic events. Compared with the overall population, patients with preexisting symptomatic atherosclerotic disease had elevated event rates for the end point of IS, MI, or vascular death; 3-year rates were 20.4% with clopidogrel and 23.8% with ASA (absolute risk reduction, 3.4%; 95% CI, -0.2 to 7.0; number needed to treat, 29; relative risk reduction, 14.9%; P=0.045). Similar results were obtained for the end point of IS, MI, or rehospitalization for ischemia; 3-year event rates were 32.7% with clopidogrel and 36.6% with ASA (absolute risk reduction, 3.9%; 95% CI, -0.4 to 8.1; number needed to treat, 26; relative risk reduction, 12.0%; P=0.039). CONCLUSIONS: CAPRIE patients with a history of prior symptomatic atherosclerotic disease had a high rate of subsequent ischemic events. The absolute benefit of clopidogrel over ASA seemed to be amplified in such high-risk patients.