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Does Anticoagulant Control Change Following Referral Back to the Primary Care Physician?

This study has been completed.
Information provided by:
University of Alberta Identifier:
First received: August 12, 2008
Last updated: June 23, 2010
Last verified: June 2010
Warfarin is a medication typically referred to as a blood thinner and is used to prevent the formation of blood clots, and hence prevent life-threatening events such as strokes and clots on the lungs (known as pulmonary emboli). This therapy is only safe and effective if the degree of blood thinning is kept within a narrow window - if the blood is "too thick" clots may form but if the blood is "too thin" the risk of bleeding increases. Complicating the control of warfarin is that different people require different amounts of it to have an appropriate degree of blood thinning, and once this amount is determined for a patient, it may be changed by factors that are encountered on a daily basis (i.e., diet, acute and chronic diseases, alcohol, medications, etc.). As such, regular monitoring is necessary to confer the benefits of this medication. Our Anticoagulation Management Service (AMS) has demonstrated really good control of blood thinning therapy by working with patients to inform them of the rationale for this medicine, the factors having the ability to impact its control, and encouraging the patient to be involved in their care (via provision of tools to document test results, one-on-one education and access to our program at any time with questions, etc.) Currently, our AMS has to limit the volume of patients seen due to resource limitations. As such, it is imperative that we investigate alternate strategies to manage these patients. Paramount, however, is that any long-term strategy must not confer inferior control of warfarin. The purpose of this study is to determine if the impact of AMS Care is sustained following the transfer of anticoagulation management to the family doctor. Operationally, the results of this study will guide future management of patients. If control of warfarin therapy declines with family doctor management, alternate strategies, such as patient self-management, will need to be investigated in a larger scale trial.

Condition Intervention Phase
Warfarin Other: anticoagulation clinic care Other: usual care Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Health Services Research
Official Title: Does Anticoagulant Control Change Following Referral Back to the Primary Care Physician? A Prospective Randomized Trial

Resource links provided by NLM:

Further study details as provided by University of Alberta:

Primary Outcome Measures:
  • Adequacy of anticoagulation control (proportion of time in the therapeutic anticoagulation range +/- 0.5 INR unit) by the Rosendaal method. [ Time Frame: 6 months ]

Secondary Outcome Measures:
  • Time within expanded therapeutic range (+/- 0.7 INR unit) by the Rosendaal method [ Time Frame: 6 months ]
  • Rates of thrombosis between groups [ Time Frame: 6 months ]
  • Rates of major hemorrhage between groups [ Time Frame: 6 months ]
  • Patient satisfaction via postal survey [ Time Frame: 6 months ]
  • Rate of crossover from primary care physician group back to anticoagulation management service [ Time Frame: 6 months ]

Estimated Enrollment: 96
Study Start Date: November 2007
Study Completion Date: April 2010
Primary Completion Date: April 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: 1
Patient continues to receive anticoagulation care from the Anticoagulation Management Service
Other: anticoagulation clinic care
Patient receives care from the outpatient anticoagulation management service
Active Comparator: 2
Patient receives anticoagulation care from their usual primary care physician
Other: usual care
patient receives usual anticoagulation care from their regular primary care physician


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • current patient of the Anticoagulation Management Service
  • anticipated need for long term anticoagulation
  • have a regular primary care physician

Exclusion Criteria:

  • previous failure of warfarin therapy (a bleed or clot despite therapeutic anticoagulation
  • have a planned procedure (surgery) mandating discontinuation of warfarin
  • are taking warfarin for a mechanical valve indication
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00735189

Canada, Alberta
University of Alberta
Edmonton, Alberta, Canada, T6G 2C8
Sponsors and Collaborators
University of Alberta
Principal Investigator: Tammy J Bungard, PharmD University of Alberta
  More Information

Responsible Party: Dr. Tammy J. Bungard, University of Alberta Identifier: NCT00735189     History of Changes
Other Study ID Numbers: epicore ams1
Study First Received: August 12, 2008
Last Updated: June 23, 2010

Keywords provided by University of Alberta:
anticoagulation clinics

Additional relevant MeSH terms:
Anticoagulants processed this record on July 25, 2017