Clinical impact of early clopidogrel discontinuation following acute myocardial infarction hospitalization or stent implantation: analysis in a nationally representative managed-care population

ABSTRACT

Objectives: To evaluate the association between discontinuation of clopidogrel therapy and risk of acute myocardial infarction (AMI) hospitalization or cardiac revascularization in a nationally-representative patient population following hospitalization for an AMI or coronary stent insertion.

Research design and methods: This observational cohort study was performed using data on patients from the PharMetrics Anonymous Patient-Centric Database who were hospitalized for an AMI or coronary stent insertion and subsequently treated with clopidogrel. Cox proportional hazard modeling was used to evaluate the association between clopidogrel discontinuation prior to 1 year post-initial AMI hospitalization and the primary endpoint of repeat AMI hospitalization or coronary intervention defined as percutaneous coronary intervention (PCI) with or without stent, or coronary artery bypass graft (CABG).

Main outcome measures: The main outcome for this study was AMI hospitalization or coronary intervention defined as PCI with or without stent placement or CABG.

Results: A total of 31 835 patients were included in the analyses. Patients were predominantly male and the average patient age was approximately 60 years. After controlling for baseline patient characteristics and follow-up time, discontinuation of clopidogrel was associated with a significantly higher rate of hospitalization for AMI or coronary intervention (HR 1.34, 95% CI 1.22–1.44).

Conclusion: Within a population of ACS patients drawn from a database of 85 US health plans, clopidogrel discontinuation within 1 year following hospitalization for AMI or stent placement is associated with an increased risk of AMI hospitalization or coronary intervention. The results of this study should be interpreted within the context of observational research, which does not address cause and effect relationships.

Key words: :

• Acute coronary syndrome
• Clopidogrel
• Myocardial infarction
• Stent

Transparency

Declaration of funding

Sanofi-aventis and Bristol-Myers Squibb funded this research and the agency of the professional medical writers who authored this paper.

Declaration of financial/other relationships

D.W., A.O. and R.C. have disclosed that they are employed by Analytica International which received funding from sanofi-aventis and Bristol-Myers Squibb. D.M. has disclosed that she is employed by Bristol-Myers Squibb. E.M. has disclosed that he is employed by sanofi-aventis.

J.C. has disclosed that he has received study funding from Kaleida Foundation and Bristol-Myers Squibb/sanofi-aventis and research funding from numerous pharmaceutical companies. He has also served as a consultant for sanofi-aventis and on the speakers’ bureau of Abbott, AstraZeneca, GlaxoSmithKline and sanofi-aventis.

All peer reviewers receive honoraria from CMRO for their review work. The peer reviewers of this paper have disclosed that they have no relevant financial relationships.

Acknowledgment

Editorial assistance was provided by Jacob M. Willet, MPH, Analytica International, New York, NY, USA.

These data were presented in part at Academy of Managed Care Pharmacy Educational Conference, October 2008, Kansas City, MO, USA.