Early Identification of Warfarin Maintenance Dosage

Phase 3

Completed

• Conditions: Atrial Fibrillation
• Interventions: Genetic: Calculate warfarin dose using demographic/genetic algorithm

• Registration Number: NCT01178034
• Lead Sponsor: University of Padova

Brief Summary

Initiation of warfarin therapy is problematic. The investigators goal was to evaluate if a new demographic/pharmacogenetic algorithm is better than a usual algorithm based on INR value at day five after four days of 5 mg/day warfarin. To this end patients with atrial fibrillation starting warfarin are randomized in two arms.

Detailed Description

The objective of this randomized study is to evaluate the accuracy of a new demographic/pharmacogenetic as compared to usual warfarin dosing algorithm in predicting warfarin maintenance dose. In patients with atrial fibrillation starting anticoagulation, the loading dose of warfarin in the tested group is calculated on the basis of VKORC1 genotype and patient's body weight.The second day warfarin maintenance dose is calculated on the basis of surface area and CYP2C9, CYP4F2 e VKORC1 genotype. In the usual care group the maintenance dose at day 5 is calculated on the basis of a published algorithm (Pengo V, Am J Cardiol 2001). INR is checked on day 0, 5, 7, 9, 12, 15 and 19. Primary end-point of the trial is the number of INR outside the therapeutic range of 2.0 to 3.0. Secondary end-points are the number of changes in dose prescription, the difference between predicted and actual warfarin maintenance dose and thrombotic and bleeding events.

Study Timeline

• Study Start: 2009-10
• Study First Submitted: 2010-08-06
• Study First Submitted QC: 2010-08-06
• Study First Posted: 2010-08-09
• Status Verified: 2012-10
• Primary Completion: 2012-10
• Study Completion: 2012-10
• Last Update Submitted: 2012-10-21
• Last Update Posted: 2012-10-23

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 180

Inclusion Criteria

• Age >18 years
• Indication to warfarin with INR between 2.0 and 3.0

Exclusion Criteria

• Pregnancy
• Drug interactions
• Basal INR > 1.2

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
pharmacogenetic warfarin dose	Calculate warfarin dose using demographic/genetic algorithm	Warfarin maintenance dose on the basis of demographic/pharmacogenetic data

Primary Outcome Measures

Name	Time	Method
International Normalized Ratio (INR)	Day 0, 5, 7, 9, 12, 15, 19.	Number of INR outside the therapeutic range (INR 2.0-3.0)

Secondary Outcome Measures

Name	Time	Method
Number of changes in warfarin dosage	Day 0-19
Difference between predicted and actual warfarin maintenance dose	Day 19
Thromboembolic and Bleeding complications	Day 0-30

Trial Locations

Locations (1)

Thrombosis Centre; 🇮🇹 Padova, Italy