WithdrawnPhase 3

Prolongation of the Interval Between Prothrombin Time Tests in Stable Patients II

Stopped: No funding obtained

Canada0Started 2014-04

Plain-language summary

More than 2 million patients in North America are treated with warfarin - a "blood thinner" - to prevent blood clots in arteries or veins. The treatment has to be monitored with a blood test and the dose changed accordingly every 1-4 weeks. One third of the patients have very stable results and hardly ever have to change the dose. The investigators wish to show that the level of control of the treatment with warfarin in these very stable patients is not worse with 12-weekly testing. A pilot study the investigators performed indicated that 12-weekly testing would be safe but this has to be confirmed in a large study. One third of patients taking warfarin have not had any changes in the dose for the past 6 months or longer. These patients will be asked about participation in the study. They will be randomized to testing and dosing every 4 or 12 weeks. Each patient is in the study until it ends, which will be minimum 1 year and can be up to about 4 years. The study is designed to show that 12-weekly testing does not significantly increase the risk for major bleeding or blood clots. The results would be important for a large number of patients. An increase of the interval between blood tests from 4 to 12 weeks would reduce the burden for these patients on life-long treatment considerably.

Who can participate

Age range

18 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * long-term warfarin for prophylaxis of arterial embolism due to atrial fibrillation or mechanical heart valve replacement OR secondary prophylaxis after VTE * therapeutic INR range of 2.0-3.0 or 2.5-3.5 * anticoagulation therapy has been managed by the study site for at least 6 months prior to enrollment * warfarin maintenance dose has remained unchanged for the previous 6 months or longer Exclusion Criteria: * Age \< 18 years * Life expectancy of less than 1 year * Congestive heart failure or other diagnosis where the condition or its treatment is expected to affect the stability of INR (e.g. cancer requiring chemotherapy) * Attending physician believes that patient is not suitable for the study (for instance, psychiatric disorder; history of non-compliance; newly diagnosed disease which by itself, via the treatment required or the effects thereof may cause instability of INRs) * Patients who perform self-testing * Geographic inaccessibility * Failure to obtain written consent

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Composite of major bleeding and objectively verified arterial or venous thromboembolism

Timeframe: Average 3 years

Trial details

NCT IDNCT01654042

SponsorMcMaster University

Sponsor typeOTHER

Study typeINTERVENTIONAL

Primary completion2018-04

View on ClinicalTrials.gov More Atrial Fibrillation trials