Date of Award


Degree Type

Selective Evidence-Based Medicine Review

Degree Name

Master of Science in Health Sciences - Physician Assistant

Department Chair

John Cavenagh, PhD, PA-C


OBJECTIVE: The objective of this selective EBM review is to determine whether or not “Is the combination therapy of clopidogrel (Plavix) and aspirin compared to antithrombotic single therapy is safe and effective in the prevention of stroke in adults?”

STUDY DESIGN: Review of three, English language, double-blinded, randomized controlled trial studies with an intention-­‐to-­‐treat basis published in 2004-2010.

DATA SOURCES: Three randomized controlled trial studying the safety and effectiveness of the combination therapy of clopidogrel (Plavix) and Aspirin compared to antithrombotic single therapy in the prevention of stroke in adults.

OUTCOME (S) MEASURED: Outcomes measured were prevention of stroke, which was measured by randomly assigned patients with evident cardiovascular disease or multiple risk factors who received clopidogrel plus low dose aspirin or placebo plus low dose antithrombotic. These were then followed during a 28-month period while observing the number of strokes that occurred within that time period, life-threatening or major bleeding occurrences. Severity of stroke in one study was measured with mRS score at 3 months after the stroke in one study. The (mRS) Modified Rankin Scale is defined as the functional severity of the first stroke outcome event at 3 months after the event. It is measured by assessing all ADLs patients could actually do (waking, bathing, dressing, grooming) after a stroke. Data was analyzed on an intention-to-treat basis. The other two studies measured the risk of life-threatening or major bleeding by the number of occurrences during a 28 month follow up.

RESULTS: The articles reviewed showed that there was no significant benefit associated with clopidogrel (Plavix) plus aspirin as compared with antithrombotic single therapy in reducing the incidence of stroke. Furthermore, in the article by Bhatt showed how the risk of moderate-to-severe bleeding was increased

CONCLUSION: Based on the articles reviewed, the difference between clopidogrel and aspirin was not statistically significant or more effective than single antithrombotic therapy alone in reducing the rate of stroke. Furthermore the use of combination therapy increased the risk of moderate to severe bleeding.