Objective: To assess the effectiveness of long term treatment with clopidogrel of patients with extracardiac vascular disease (ECVD) (a history of either peripheral arterial disease or cerebrovascular disease).
Design: Subgroup analysis of a prospective randomised clinical trial.
Setting: The CREDO (clopidogrel for the reduction of events during observation) trial was a randomised, double blind, placebo controlled trial conducted at 99 centres in North America from June 1999 through April 2001.
Patients: 2116 patients who were to undergo elective coronary intervention or were deemed at high likelihood of undergoing percutaneous coronary intervention were enrolled in the CREDO trial. The current study sample consisted of 272 patients with ECVD.
Main outcome measure: One year incidence of the composite of death, myocardial infarction, or stroke in the intent to treat population.
Results: Patients with ECVD had a more than twofold greater relative risk reduction with clopidogrel for the primary end point compared with patients without ECVD (47.9%, 95% confidence interval (CI) -4.2% to 73.9%, v 18.2%, 95% CI -10.5 % to 39.5%, respectively).
Conclusions: Longer term clopidogrel treatment provides added protection against thrombotic events throughout the arterial vasculature, not limited to the coronary arteries, and may be especially effective for patients with more diffuse atherosclerosis such as ECVD.