Randomized Controlled Feasibility Trial of the Fearon Algorithm to Improve Management of Unstable Warfarin

Hypoprothrombinemia Clinical Trial

Official title:

A Single-site, Randomized Controlled Feasibility Trial of the Fearon Algorithm to Improve Management of Patients With Unstable Warfarin Effect.

Clinical Trial Details — Status: Terminated

Administrative data

• NCT number: NCT02267408
• Other study ID #: Fearon pilot RCT, version 03
• Status: Terminated
• Phase: Phase 1/Phase 2
• First received: October 14, 2014
• Last updated: April 4, 2018
• Start date: November 2014
• Est. completion date: February 3, 2017

Study information

• Verified date: March 2016
• Source: McMaster University
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

Patients on warfarin but with unstable international normalized ratio (INR) will be recruited to a randomized trial comparing dosing based on an algorithm (Fearon algorithm, named after the mathematician Michael Fearon), which uses historical data to estimate patients' sensitivity to warfarin and to dose changes as well as the lag time until a dose adjustment takes effect, or to the investigators standard management Main outcome is improvement in time in therapeutic range.

Description:

Patients with very variable INRs resulting in a low proportion of time in therapeutic range (TTR) have a higher risk of both bleeding complications and thromboembolic events. A good TTR is generally considered to be over 60% and "excellent TTR" is above 72% of time in range. The investigators will recruit patients with a TTR below 50%.

The Fearon algorithm provides a more thorough understanding of the individual responses to changes in warfarin dose and with a personalized nomogram for dose adjustments and timing of laboratory tests the investigators have an opportunity to improve the TTR and on a larger scale to reduce clinically important adverse events. Before embarking on a large randomized trial with this revised Fearon algorithm-derived nomogram this pilot study with a randomized, open-label design will be performed to demonstrate proof of principle.

Recruitment information / eligibility

• Status: Terminated
• Enrollment: 42
• Est. completion date: February 3, 2017
• Est. primary completion date: February 2017
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• Patients with mechanical heart valve prosthesis managed for the warfarin therapy by the Thrombosis Service at HHS-General Hospital.

• Treated with warfarin for at least 1 year.

• Therapeutic INR range 2.0-3.0 or 2.5-3.5.

• TTR in the lowest quartile

Exclusion Criteria:

• Known poor compliance due to for example alcohol abuse or cognitive impairment

• Refusal to provide written informed consent

Related Conditions & MeSH terms

• Hypoprothrombinemia

Intervention

Other:
• Warfarin adjustment using the Fearon algorithm
All available historical data will be used to calculate with the Fearon algorithm the individual sensitivity to warfarin and to dose changes as well as lag time until a dose adjustment reaches full effect. Based on this a personal dosing nomogram will be developed and provided to the investigator and to the patients. This nomogram will be used during 6 month but override is possible if the investigator feels that the suggestion from the nomogram is unsafe.
• Warfarin adjustment using standard dosing
Patients will receive warfarin dosing instructions from a trained nurse using fixed nomograms and computer-based dosing suggestion.

Locations

Country	Name	City	State
Canada	Thrombosis Service, HHS-General Hospital	Hamilton	Ontario

Sponsors (2)

Lead Sponsor	Collaborator
McMaster University	Epitome Pharmaceuticals

Country where clinical trial is conducted

Canada, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Improvement in TTR	The percent units of TTR during the 6 months will be compared with the percent units TTR in the previous year	6 months
Secondary	Proportion of patients with improvement in TTR	Proportion of included patients with TTR improvement of more than 5 percent units	6 months