Patient Self Testing of Warfarin Therapy

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

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

Conditions
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Warfarin

Intervention / Treatment
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* Device: CoaguChek (Patient self testing)
* Device: Anticoagulation Management Service (AMS)


Participation Criteria
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Eligibility Criteria
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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
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 1<br>6 months of supervised patient self testing using an expert system | Device: CoaguChek (Patient self testing)<br>* 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<br>* Other names: CoagCare expert system;|
| Active Comparator: 2<br>6 months of routine medical care by the anticoagulation management service | Device: Anticoagulation Management Service (AMS)<br>* 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<br>|

What is the study measuring?
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Primary Outcome Measures

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

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Patient self-testing, Oral anticoagulation therapy, Expert Systems, Point-of-Care Systems, International Normalized Ratio