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Randomized Comparison of Warfarin Dosing Quality Between the Hamilton Nomogram and a Commercial Computer System

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: NCT01024452
Recruitment Status : Completed
First Posted : December 2, 2009
Last Update Posted : July 20, 2011
Information provided by:
Population Health Research Institute

Brief Summary:

Randomized comparison of warfarin dosing quality between the Hamilton nomogram and a commercial computer system.

Hypothesis: Mean TTR of patients managed with the commercial computer system is non-inferior to management with the validated Hamilton Nomogram.

Condition or disease Intervention/treatment Phase
Patients at Risk for Thrombosis Device: DAWN AC Device: Hamilton Nomogram Phase 3

Detailed Description:
Warfarin has a variable effect and many potential food and drug interactions. To have an optimal therapeutic effect the International Normalized Ratio (INR) needs to be maintained within the therapeutic target range. The time that a patient spends within the therapeutic target range is an intermediate quality indicator for patient outcomes and should be optimized. For this purpose, we use in our anticoagulation clinic the simple two-step Hamilton nomogram, which has been validated by Kim et al. who showed that the nomogram improved INR control for warfarin maintenance compared with expertise-based dosing in our anticoagulation clinic (see references). Computer systems are also known to outperform expertise-based dosing, but no direct comparison of a computer system with a simple nomogram has been assessed. In this single-center randomized controlled clinical trial we will compare the simple two-step Hamilton nomogram with the widely used computerized dosing management system DAWN AC regarding their effect on time in therapeutic range for patients on maintenance dosing with target range 2-3.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 1298 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Participant)
Primary Purpose: Treatment
Official Title: Randomized Comparison of Warfarin Dosing Quality Between the Hamilton Nomogram and a Commercial Computer System
Study Start Date : November 2009
Actual Primary Completion Date : August 2010
Actual Study Completion Date : August 2010

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Blood Thinners
Drug Information available for: Warfarin

Arm Intervention/treatment
Experimental: DAWN AC Device: DAWN AC
computerized dosing management system for anticoagulation clinics
Other Name: DAWN AC, 4S Information Systems Ltd.

Active Comparator: Hamilton Nomogram Device: Hamilton Nomogram
simple nomogram for warfarin maintenance dosing
Other Name: Nomogram (algorithm)

Primary Outcome Measures :
  1. TTR: The proportion of time a patient spends in the therapeutic INR range (2-3) [ Time Frame: TTR calculated over the entire study period (6 months) ]

Information from the National Library of Medicine

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

Inclusion Criteria:

  • On warfarin maintenance therapy
  • INR target range 2-3
  • At least 3 historical INRs on maintenance therapy
  • At least 1 historical INR in the last 3 months

Exclusion Criteria:

  • Participation in another study
  • On multiple pill strengths

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01024452

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Canada, Ontario
Hamilton General Hospital
Hamilton, Ontario, Canada, L8L 2X2
Sponsors and Collaborators
Population Health Research Institute
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Principal Investigator: Stuart Connolly, MD Director, Division of Cardiology
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Responsible Party: Dr. S. Connolly, Population Health Research Institute Identifier: NCT01024452    
Other Study ID Numbers: 09-283
First Posted: December 2, 2009    Key Record Dates
Last Update Posted: July 20, 2011
Last Verified: December 2009
Keywords provided by Population Health Research Institute:
computer systems
international normalized ratio
Additional relevant MeSH terms:
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Embolism and Thrombosis
Vascular Diseases
Cardiovascular Diseases