Stroke and the statistics of the aspirin/clopidogrel secondary prevention trials

George Howard; Leslie A McClure; John W Krakauer; Christopher S Coffey

doi:10.1097/WCO.0b013e328013dbc8

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Stroke and the statistics of the aspirin/clopidogrel secondary prevention trials

Journal article

Peer reviewed

Stroke and the statistics of the aspirin/clopidogrel secondary prevention trials

George Howard, Leslie A McClure, John W Krakauer and Christopher S Coffey

Current opinion in neurology, Vol.20(1), pp.71-77

02/2007

DOI: 10.1097/WCO.0b013e328013dbc8

PMID: 17215692

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Abstract

Four randomized trials have investigated the combination of clopidogrel plus aspirin for secondary prevention of vascular outcomes in 54,949 patients. Here we argue that attempts to translate the results of these trials into clinical practice have proven frustrating because of the following statistical considerations: differences in study populations and study design make comparisons difficult (comparisons of 'apples and oranges'), incomplete factorial designs prevent proper contrasts (examining 'bits and pieces' of a larger picture), results concern widely different vascular diseases ('puzzling subgroups'), and negative results are easily misinterpreted. Between 1996 and 2004 three major randomized trials assessed combinations of aspirin and clopidogrel, finding: Clopidogrel versus Aspirin in Patients at Risk of Ischemic Events (CAPRIE) in favor of clopidogrel alone versus aspirin alone, Clopidogrel in Unstable Angina to Prevent Recurrent Events (CURE) in favor of clopidogrel plus aspirin versus aspirin alone, and Management of Atherothombosis with Clopidogrel in High-risk Patients (MATCH) in favor of clopidogrel plus aspirin versus clopidogrel alone. A recently completed fourth trial (Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management and Avoidance; CHARISMA) was a 'negative study' comparing aspirin alone to aspirin plus clopidogrel. Even after four large randomized trials we still do not know the optimal treatment for secondary prevention of stroke. We suggest that subsequent trials should focus on a particular vascular disease and test hypotheses that relate to a specific mechanism.

Aspirin - therapeutic use

Clinical Protocols - standards

Clinical Trials as Topic - methods

Clinical Trials as Topic - standards

Clinical Trials as Topic - statistics & numerical data

Data Interpretation, Statistical

Drug Therapy, Combination

Humans

Platelet Aggregation Inhibitors - therapeutic use

Reproducibility of Results

Stroke - drug therapy

Stroke - physiopathology

Stroke - prevention & control

Ticlopidine - analogs & derivatives

Ticlopidine - therapeutic use

Treatment Outcome

Details

Title: Subtitle: Stroke and the statistics of the aspirin/clopidogrel secondary prevention trials
Creators: George Howard - Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama 35294-0022, USA. ghoward@uab.edu
Leslie A McClure
John W Krakauer
Christopher S Coffey
Resource Type: Journal article
Publication Details: Current opinion in neurology, Vol.20(1), pp.71-77
DOI: 10.1097/WCO.0b013e328013dbc8
PMID: 17215692
ISSN: 1350-7540
eISSN: 1473-6551
Language: English
Date published: 02/2007
Academic Unit: Biostatistics
Record Identifier: 9984214669702771

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9 Times Cited - Web of Science