Prospective Evaluation of an Extended Interval of INR Follow-up in a VA Anticoagulation Service
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ClinicalTrials.gov Identifier: NCT02392104 |
Recruitment Status :
Completed
First Posted : March 18, 2015
Results First Posted : December 11, 2019
Last Update Posted : December 11, 2019
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The purpose of this study is to determine the feasibility, safety, and acceptability of implementing an extended interval of INR follow-up in Veterans on a stable dose of warfarin in the Anticoagulation Clinic at the William S. Middleton Memorial Veterans Hospital.
All participants will be provided usual care from the anticoagulation clinic, except for the interval between INRs. If the participant continues to be on a stable dose of warfarin and the INRs are within the goal range of 2-3 (including lab variation), follow-up visits will be scheduled following an extended interval protocol. Patient satisfaction will be evaluated at various points throughout the study. Additionally provider satisfaction, confidence, and knowledge of the extended interval protocol will be analyzed. Bleeding and thromboembolic events will be evaluated to ensure the safety of an extended follow-up interval.
Condition or disease | Intervention/treatment | Phase |
---|---|---|
Anticoagulation | Drug: Warfarin | Not Applicable |
The purpose of this study is to determine the feasibility, safety, and acceptability of implementing an extended interval of INR follow-up in Veterans on a stable dose of warfarin in the Anticoagulation Clinic at the William S. Middleton Memorial Veterans Hospital.
All participants will be provided usual care from the anticoagulation clinic, except for the interval between INRs. If the participant continues to be on a stable dose of warfarin and the INRs are within the goal range of 2-3 (including lab variation), follow-up visits will be scheduled following an extended interval protocol, from 5-6 weeks, to 7-8 weeks, to 11-12 weeks and then continued with 11-12 week visits if INRs continue to remain in goal range and appropriate for the patient. Patient satisfaction will be evaluated at baseline, 6-, 12-, and 24-months. Additionally provider satisfaction, confidence, and knowledge of the extended interval protocol will be analyzed. Bleeding and thromboembolic events will be evaluated to ensure the safety of an extended follow-up interval.
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 51 participants |
Intervention Model: | Single Group Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | Prospective Evaluation of an Extended Interval of INR Follow-up in a VA Anticoagulation Service |
Actual Study Start Date : | March 27, 2015 |
Actual Primary Completion Date : | June 25, 2017 |
Actual Study Completion Date : | June 25, 2017 |

Arm | Intervention/treatment |
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Experimental: Intervention Arm
All patients in the study will be in the intervention arm.
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Drug: Warfarin
If the patient's INRs stay within goal range, their interval of INR follow-up will be extended based on a protocol to a maximum of 12 weeks.
Other Name: Coumadin |
- Rates of Participant Accrual [ Time Frame: up to 2.25 years ]Number of participants who enroll vs. number of individuals invited
- Number of Participants Able to be Scheduled for at Least One 12-week Interval [ Time Frame: 24 months ]This outcome will determine the number of participants able to be scheduled for at least one 12-week interval
- Number of Participants Scheduled for at Least 4 Consecutive 12-week Intervals [ Time Frame: 24 months ]The outcome will determine the number of participants scheduled for at least 4 consecutive 12-week intervals
- Change in Frequency of Appointments From Baseline to End of Study [ Time Frame: 12 and 24 months ]This outcome will evaluate the change in frequency of appointments from baseline to end of study (at 12 and 24 months)
- Bleeding and Thromboembolic Events From Baseline [ Time Frame: 24 months ]This outcome will determine the number of bleeding and thromboembolic events from baseline
- Change in Time in Therapeutic Range From Baseline [ Time Frame: 6, 12, and 24 months ]The outcome will evaluate the change in time in therapeutic range (TTR) from baseline (intention-to-treat)
- Patient Satisfaction Through Total DASS Score [ Time Frame: baseline, 6 months, 12 months, 24 months ]Patient satisfaction through total DASS score. DASS = Duke Anticoagulation Satisfaction Scale. 25-item scale.Higher numbers indicate worsening satisfaction ranging from 25-175. Seven-point ordinal scale ("not at all" = 1, "very much" = 7).
- Frequency and Type of Protocol Deviations From Both Participants and Study Staff [ Time Frame: Up to 2.25 years ]This outcome determines the frequency and type of protocol deviations from both participants and study staff

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Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- 18 years of age or older
- requirement for indefinite warfarin therapy
- target INR of 2-3
- stable weekly warfarin dose for the past 6 months (not more than a single, one-time adjustment (boost/omission) in the past 6 months, planned interruption for a procedure or surgery with INR(s) out of range in the past 6 months would not exclude a patient)
- a patient of the Madison VA anticoagulation clinic for the previous 12 months
Exclusion Criteria:
- consistently drink ≥4 alcoholic beverages/day or a documented episode of alcohol binging in the past 6 months
- diagnosis of cancer and on active chemotherapy/radiotherapy in the past 3 months
- life expectancy of < 1 year
- enrolled in other investigational drug protocols
- only receiving anticoagulation care at the Madison VA for part of the year (e.g. snowbirds)
- receiving visiting nurse services for INR monitoring
- thrombocytopenia (<100K) within past 12 months
- history of bleeding or thromboembolism requiring medical intervention within past 6 months
- treatment for active liver disease (e.g. hepatitis)
- diagnosis or documentation in EMR suggesting cognitive impairment
- activated power of attorney
- inability to provide informed consent
- non-English speaking
- unstable mental health disorder that impairs judgment
- history of non-adherence to anticoagulation clinic policies and procedures (i.e. missed appointments, self-adjustment of warfarin dose, nonadherence, etc.).

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02392104
Principal Investigator: | Carla Staresinic, PharmD | William S. Middleton Memorial Veterans Hospital |
Documents provided by Carla Staresinic, William S. Middleton Memorial Veterans Hospital:
Responsible Party: | Carla Staresinic, Manager, Anticoagulation Services, William S. Middleton Memorial Veterans Hospital |
ClinicalTrials.gov Identifier: | NCT02392104 History of Changes |
Other Study ID Numbers: |
2014-1296 |
First Posted: | March 18, 2015 Key Record Dates |
Results First Posted: | December 11, 2019 |
Last Update Posted: | December 11, 2019 |
Last Verified: | November 2019 |
International Normalized Ratio Warfarin |
Warfarin Anticoagulants |