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

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.

Study Overview

• Status: Completed
• Conditions: Anticoagulation
• Intervention / Treatment: Drug: Warfarin

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.

• Study Type: Interventional
• Enrollment (Actual): 51
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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.).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention Arm; All patients in the study will be in the intervention arm.	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 Names: Coumadin

What is the study measuring?

Primary Outcome Measures

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

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Frequency of Appointments From Baseline to End of Study	This outcome will evaluate the change in frequency of appointments from baseline to end of study (at 12 and 24 months)	12 and 24 months
Bleeding and Thromboembolic Events From Baseline	This outcome will determine the number of bleeding and thromboembolic events from baseline	24 months
Change in Time in Therapeutic Range From Baseline	The outcome will evaluate the change in time in therapeutic range (TTR) from baseline (intention-to-treat)	6, 12, and 24 months
Patient Satisfaction Through Total DASS Score	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).	baseline, 6 months, 12 months, 24 months

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Frequency and Type of Protocol Deviations From Both Participants and Study Staff	This outcome determines the frequency and type of protocol deviations from both participants and study staff	Up to 2.25 years

Collaborators and Investigators

• Sponsor: William S. Middleton Memorial Veterans Hospital
• Collaborators: University of Wisconsin, Madison
• Investigators: Principal Investigator: Carla Staresinic, PharmD, William S. Middleton Memorial Veterans Hospital

Publications and helpful links

General Publications

• Schoen RR, Nagy MW, Porter AL, Margolis AR. Patient Satisfaction With Extended International Normalized Ratio Follow-up Intervals in a Veteran Population. Ann Pharmacother. 2020 May;54(5):442-449. doi: 10.1177/1060028019889414. Epub 2019 Nov 21.

Study record dates

Study Major Dates

• Study Start (Actual): March 27, 2015
• Primary Completion (Actual): June 25, 2017
• Study Completion (Actual): June 25, 2017

Study Registration Dates

• First Submitted: February 25, 2015
• First Submitted That Met QC Criteria: March 17, 2015
• First Posted (Estimate): March 18, 2015

Study Record Updates

• Last Update Posted (Actual): December 11, 2019
• Last Update Submitted That Met QC Criteria: November 21, 2019
• Last Verified: November 1, 2019

More Information

Terms related to this study

• Keywords: Warfarin; International Normalized Ratio
• Additional Relevant MeSH Terms: Anticoagulants; Warfarin
• Other Study ID Numbers: 2014-1296