Prospective Evaluation of an Extended Interval of INR Follow-up in a VA Anticoagulation Service

Not Applicable

Completed

Brief Summary: 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.

Detailed Description: 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.

Recruitment & Eligibility

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.).

Arm && Interventions

Group	Intervention	Description
Intervention Arm	Warfarin	All patients in the study will be in the intervention arm.

Primary Outcome Measures

Name	Time	Method
Rates of Participant Accrual	up to 2.25 years	Number of participants who enroll vs. number of individuals invited
Number of Participants Scheduled for at Least 4 Consecutive 12-week Intervals	24 months	The outcome will determine the number of participants scheduled for at least 4 consecutive 12-week intervals
Number of Participants Able to be Scheduled for at Least One 12-week Interval	24 months	This outcome will determine the number of participants able to be scheduled for at least one 12-week interval

Secondary Outcome Measures

Name	Time	Method
Change in Frequency of Appointments From Baseline to End of Study	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	24 months	This outcome will determine the number of bleeding and thromboembolic events from baseline
Change in Time in Therapeutic Range From Baseline	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	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).