Assessing the Ability of Warfarin Treated Patients to Predict Their INR

Study Overview
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Brief Summary
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ASSESSING THE ABILITY OF WARFARIN TREATED PATIENTS TO PREDICT THEIR INR Kathleen McNamara, James Hoehns, Matthew Witry The international normalized ratio (INR) is the accepted lab test used to measure the intensity of warfarin effect. The conventional wisdom is that patients receiving warfarin are unable to correctly determine, in the absence of an INR result, whether or not they are therapeutic at any given time. Some warfarin treated patients express that they have insight into what their INR result will be. Various patient related factors may contribute to these opinions. Our objective is to assess how accurately patients can guess their INR result before it is obtained and to describe factors which inform their opinion of what their INR will be.

Detailed Description
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ASSESSING THE ABILITY OF WARFARIN TREATED PATIENTS TO PREDICT THEIR INR Kathleen McNamara, James Hoehns, Matthew Witry The international normalized ratio (INR) is the accepted lab test used to measure the intensity of warfarin effect. The conventional wisdom is that patients receiving warfarin are unable to correctly determine, in the absence of an INR result, whether or not they are therapeutic at any given time. Some warfarin treated patients express that they have insight into what their INR result will be. Various patient related factors may contribute to these opinions. Our objective is to assess how accurately patients can guess their INR result before it is obtained and to describe factors which inform their opinion of what their INR will be. In this prospective study, the investigators will enroll warfarin treated patients from 7 anticoagulation clinics in Iowa. Inclusion criteria are: age ≥18 years, warfarin use ≥60 days, INR goal of 2.0-3.0 or 2.5-3.5, expected warfarin use >6 months, and English speaking. Exclusion criteria include: use of self INR-testing, home INR draws, dementia, or residing in a long-term care facility. A data collection form will be completed prior to INR measurement for a 6 month period. Information will be collected for subject demographics, warfarin adherence, INR stability, INR prediction, and prediction rationale. INR monitoring represents a significant burden with respect to cost and time. The results of this study may identify patient factors which could help individualize and decrease the frequency of INR monitoring in patients who receive maintenance warfarin therapy.

Official Title
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Assessing the Ability of Warfarin Treated Patients to Predict Their INR

Conditions
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Atrial Fibrillation

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥18 years Warfarin use ≥60 days INR goal of 2.0-3.0 or 2.5-3.5 Expected warfarin use >6 months English speaking Exclusion Criteria: Self INR-testing Home INR draws Dementia Residence of a long-term care facility

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Assess factors which influence INR predictions | Patients will be asked to predict their INR value prior to having it tested. We will record patient's INR prediction and the value we obtain after testing INR. | 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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warfarin