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Aspirin and Clopidogrel Resistance Study

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01039480
Recruitment Status : Completed
First Posted : December 25, 2009
Last Update Posted : February 9, 2012
Information provided by:
University Hospital, Basel, Switzerland

Tracking Information
First Submitted Date December 23, 2009
First Posted Date December 25, 2009
Last Update Posted Date February 9, 2012
Study Start Date May 2010
Actual Primary Completion Date June 2011   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures
 (submitted: December 24, 2009)
Platelet aggregation, initial and after one week under compliance monitoring. [ Time Frame: 1 week ]
Original Primary Outcome Measures Same as current
Change History Complete list of historical versions of study NCT01039480 on Archive Site
Current Secondary Outcome Measures
 (submitted: December 24, 2009)
  • Data on compliance (measured by electronic compliance monitoring, Morisky MMAS-8 and BMQ Score) [ Time Frame: 1 week ]
  • Frequency of contributing factors to non-response in responders compared to non-responders (pharmacogenetics, clinical factors and drug-drug interactions) [ Time Frame: 4 weeks ]
Original Secondary Outcome Measures Same as current
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
Descriptive Information
Brief Title Aspirin and Clopidogrel Resistance Study
Official Title Aspirin- and Clopidogrel-Resistance: Non-compliance and Other Contributing Factors
Brief Summary Resistance to antiplatelet drugs (aspirin, clopidogrel) is a recognized phenomenon with a prevalence from 17% to 35%. Resistance as detected by in vitro tests such as Multiple Electrode Aggregometry (MEA) has been shown to predict clinical therapy failure. Resistance can be caused by clinical, cellular and pharmacogenetic factors. Non compliance is suspected to be an important contributing factor. In this study, compliance will be assured with an electronical compliance monitoring system. Factors to non response will be identified to find plausible explanations when in vitro platelet aggregation inhibition is insufficient despite assured compliance. This study will help to disclose the relationship between compliance, biomarker and clinical outcome as well as to quantify the impact of non compliance to the resistance phenomenon as measured by MEA.
Detailed Description Not Provided
Study Type Observational
Study Design Observational Model: Cohort
Time Perspective: Cross-Sectional
Target Follow-Up Duration Not Provided
Biospecimen Retention:   Samples With DNA
blood samples for routine laboratory testing and platelet aggregometry blood samples for pharmacogenetic analysis
Sampling Method Probability Sample
Study Population Patients with a prescription for aspirin and/or clopidogrel seeing their general practitioner (GP) for any purpose
Condition Drug Resistance
Intervention Not Provided
Study Groups/Cohorts
  • dual therapy (ASS/CLO)
    patients with a prescription for dual antiplatelet therapy with aspirin AND clopidogrel
  • clopidogrel users (CLO)
    patients with a prescription for clopidogrel
  • aspirin users (ASP)
    patients with a prescription for aspirin
Publications * Walter PN, Tsakiris DA, Romanens M, Arnet I, Hersberger KE. Antiplatelet resistance in outpatients with monitored adherence. Platelets. 2014;25(7):532-8. doi: 10.3109/09537104.2013.845743. Epub 2013 Oct 31.

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
Recruitment Information
Recruitment Status Completed
Actual Enrollment
 (submitted: February 8, 2012)
Original Estimated Enrollment
 (submitted: December 24, 2009)
Actual Study Completion Date October 2011
Actual Primary Completion Date June 2011   (Final data collection date for primary outcome measure)
Eligibility Criteria

Inclusion Criteria:

  • Patients prescribed aspirin and/or clopidogrel for both including both cardiovascular and cerebrovascular indications seeing their general practitioner in or nearby Olten/SO for any medical purpose
  • Patients with oral and written German language ability

Exclusion Criteria:

  • Patients living in care homes
  • Patients not preparing their drugs on their own (e.g. outpatient medical assistance through "spitex").
  • Patients with acute cardiac symptoms
Sexes Eligible for Study: All
Ages 45 Years and older   (Adult, Older Adult)
Accepts Healthy Volunteers No
Contacts Contact information is only displayed when the study is recruiting subjects
Listed Location Countries Switzerland
Removed Location Countries  
Administrative Information
NCT Number NCT01039480
Other Study ID Numbers PCRG_003_PW
Has Data Monitoring Committee No
U.S. FDA-regulated Product Not Provided
IPD Sharing Statement Not Provided
Responsible Party Philipp N. Walter, Investigator, Pharmaceutical Care Research Group
Study Sponsor University Hospital, Basel, Switzerland
Collaborators Not Provided
Study Chair: Kurt E Hersberger, PhD Pharmaceutical Care Research Group, Departement of Pharmacy, University Basel
Principal Investigator: Michel Romanens, MD Kardiologische Praxis, Olten/SO
Study Director: Dimitrios Tsakiris, MD Hemostaseology Lab, University Hospital Basel
Principal Investigator: Philipp N Walter, MSc Pharmaceutical Care Research Group, Department of Pharmacy, University of Basel
PRS Account University Hospital, Basel, Switzerland
Verification Date February 2012