Clinical trial NCT01024452: Randomized Comparison of Warfarin Dosing Quality Between the Hamilton Nomogram and a Commercial Computer System
Official title: Randomized Comparison of Warfarin Dosing Quality Between the Hamilton Nomogram and a Commercial Computer System
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE3
Conditions: Patients at Risk for Thrombosis
Keywords: anticoagulation
warfarin
computer systems
international normalized ratio
nomograms
Lead sponsor: Population Health Research Institute
Sponsor class: OTHER
First posted: 2009-12-02
Enrollment: 1298
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

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.

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.

Eligibility criteria: 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

Primary outcomes:
measure: TTR: The proportion of time a patient spends in the therapeutic INR range (2-3)
timeFrame: TTR calculated over the entire study period (6 months)
Secondary outcomes:
Other outcomes:
Locations:
city: Hamilton
country: Canada
facility: Hamilton General Hospital
state: Ontario
Study officials:
affiliation: Director, Division of Cardiology
name: Stuart Connolly, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Poller L, Keown M, Ibrahim S, Lowe G, Moia M, Turpie AG, Roberts C, van den Besselaar AM, van der Meer FJ, Tripodi A, Palareti G, Shiach C, Bryan S, Samama M, Burgess-Wilson M, Heagerty A, Maccallum P, Wright D, Jespersen J; European Action on Anticoagulation (EAA). A multicentre randomised assessment of the DAWN AC computer-assisted oral anticoagulant dosage program. Thromb Haemost. 2009 Mar;101(3):487-94.
citation: Kim YK, Nieuwlaat R, Connolly SJ, Schulman S, Meijer K, Raju N, Kaatz S, Eikelboom JW. Effect of a simple two-step warfarin dosing algorithm on anticoagulant control as measured by time in therapeutic range: a pilot study. J Thromb Haemost. 2010 Jan;8(1):101-6. doi: 10.1111/j.1538-7836.2009.03652.x. Epub 2009 Oct 14.