Patient Self Testing of Warfarin Therapy

Randomized Controlled Trial of Patient Self-Testing of Warfarin Therapy Using an Internet Based Expert System

To test the hypothesis that home international normalised ratio (INR) monitoring with supervised patient self-testing (PST)can provide comparable or superior time in therapeutic range (TTR) to that provided by traditional outpatient anticoagulation.

Study Overview

• Status: Unknown
• Conditions: Warfarin
• Intervention / Treatment: Device: CoaguChek (Patient self testing); Device: Anticoagulation Management Service (AMS)

Detailed Description

Indications for anticoagulant treatment to prevent thromboembolic disease have increased in recent years. INR must be monitored frequently to determine the safest dose and to minimize the risk for thrombotic and haemorrhagic complications. Standard warfarin therapy is associated with rates of major haemorrhage of up to 5-9% annually and recurrent venous thromboembolism of up to 8%. These event rates are dependent of the model of care used to manage warfarin therapy, with better outcomes associated with home testing of the INR which enables patients to monitor their response to warfarin more frequently. INR results must still be 'managed' by communicating the data to the healthcare provider, usually be telephone or fax.

In this study we will evaluate a novel method of PST; supervised PST with an internet based expert system, which 'manages' patients on oral anticoagulation by utilizing clinical and laboratory data provided by the patient and dose adjustment and retesting algorithms derived from clinical practice. Patients will be randomized to either 6 months of supervised PST or routine medical care by the AMS. At the end of the 6 month period, each patient will then 'cross over' to the other management regimen and the difference in TTR between the two periods will be compared.

• Study Type: Interventional
• Enrollment (Actual): 163
• Phase: Phase 4

Contacts and Locations

Study Locations

• Ireland
  • Cork, Ireland
    • Cork University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• on warfarin therapy for a minimum of 2 months
• are expected to be on warfarin therapy for the duration of the 12 month study
• internet access

Exclusion Criteria:

• inability to provide informed consent
• inability to use a home INR meter
• patients who do not have a telephone
• more than 2 missed clinic appointments in the preceding 6 months
• patients on anticoagulant drugs other than warfarin (eg heparin, low molecular weight heparin)
• history of hemorrhagic complications with a therapeutic or therapeutic INR in the preceding 6 months
• inability to attend the hospital at short notice, if necessary

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 1; 6 months of supervised patient self testing using an expert system	Device: CoaguChek (Patient self testing); Patients will test their INR at home either biweekly, weekly or every 2 weeks using a CoaguChek point of care meter and communicate with the healthcare provider via an internet based expert system; Other Names: CoaguChek S point of care meter; CoaguChek XS point of care meter; CoagCare expert system
Active Comparator: 2; 6 months of routine medical care by the anticoagulation management service	Device: Anticoagulation Management Service (AMS); Patients will attend the AMS for six months and have their INR checked every 4-6 weeks or more frequently, at the discretion of the clinician

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
The primary outcome variable used to assess therapeutic efficacy and safety will be the difference in TTR during the six months of AMS management and the six months of PST	1 year

Secondary Outcome Measures

Outcome Measure	Time Frame
To compare the number of adverse events (haemorrhagic and thromboembolic) using PST and AMS management	1 year

Collaborators and Investigators

• Sponsor: University College Cork
• Collaborators: Hoffmann-La Roche; Health Research Board, Ireland; ZyCare Inc
• Investigators: Principal Investigator: Susan J O'Shea, MD, Cork University Hospital

Study record dates

Study Major Dates

• Study Start: July 1, 2006
• Primary Completion (Anticipated): April 1, 2009
• Study Completion (Anticipated): April 1, 2008

Study Registration Dates

• First Submitted: January 7, 2008
• First Submitted That Met QC Criteria: January 7, 2008
• First Posted (Estimate): January 16, 2008

Study Record Updates

• Last Update Posted (Estimate): January 16, 2008
• Last Update Submitted That Met QC Criteria: January 7, 2008
• Last Verified: January 1, 2008

More Information

Terms related to this study

• Keywords: Expert Systems; International Normalized Ratio; Point-of-Care Systems; Patient self-testing; Oral anticoagulation therapy
• Other Study ID Numbers: PA/05/16