The Home INR Study (THINRS)

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
Department of Veterans Affairs
ClinicalTrials.gov Identifier:
NCT00032591
First received: March 27, 2002
Last updated: March 18, 2014
Last verified: March 2014
  Purpose

Since home monitors of prothrombin time (PT) may potentially improve the safety, quality, and convenience of chronic anticoagulation management, it is likely that there will be demands from providers, patients, and manufacturers to make home monitors available to VA patients. The rationale for patient self-testing (PST) is that, compared to conventional high quality anticoagulation management (HQACM), it would permit more intense monitoring and increased patient participation in his/her own care, resulting in increased precision in anticoagulation control and thus fewer events of thromboembolism (strokes) and bleeding. The secondary hypothesis is that PST and HQACM will be comparable in terms of health care utilization and cost.


Condition Intervention Phase
Atrial Fibrillation
Procedure: Weekly patient self-testing of prothrombin time
Other: High quality anticoagulation management (HQACM) with conventional monthly testing
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: CSP #481 - The Home INR Study (THINRS)

Resource links provided by NLM:


Further study details as provided by Department of Veterans Affairs:

Primary Outcome Measures:
  • Time to First Event (Death, Stroke, Major Bleed) [ Time Frame: Time to event ] [ Designated as safety issue: Yes ]

    Time to first event (death, stroke, major bleed)

    The primary outcome was time to first event, and we used the Kaplan-Meier method to compare survival curves and the results using the log-rank test. The number of patients with a primary outcome is what was reported in the NEJM paper. Below is the unpublished cumulative incidence information.



Secondary Outcome Measures:
  • Time in Therapeutic Range Over Full Length of Follow-up (0 to 100 Percent) [ Time Frame: Full length of follow-up; average of 3 years ] [ Designated as safety issue: Yes ]
    Time in target range (TTR) based on Prothrombin Time standardized to the International Normalized Ratio

  • DASS at 2 Years of Follow-up [ Time Frame: At two years of follow-up ] [ Designated as safety issue: No ]
    Satisfaction with care was quantified using the Duke Anticoagulation Satisfaction Scale (DASS). Scores range from 25 to 225, with lower scores indicating higher satisfaction.

  • Cumulative Gain in Health Utilities at 2 Year [ Time Frame: After 2 years of follow-up for each subject ] [ Designated as safety issue: No ]
    Scores range from -0.36 to 1.00 per year, with a negative score indicating a state worse than being dead and a score of 1.00 indicating perfect health. Since the time frame is 2 years, the range is -0.72 to 2.00.

  • Health Care Costs at 2 Year [ Time Frame: After 2 years of follow-up for each subject ] [ Designated as safety issue: No ]

Enrollment: 2922
Study Start Date: August 2003
Study Completion Date: May 2008
Primary Completion Date: May 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Arm 1
Patient Self-Testing (PST) of prothrombin time by international normalized ratio (PT-INR or INR) with weekly testing
Procedure: Weekly patient self-testing of prothrombin time
Arm 2
High quality anticoagulation management (HQACM) with conventional monthly testing
Other: High quality anticoagulation management (HQACM) with conventional monthly testing
HQACM with testing every 4 weeks and as indicated for out of range values, medication/clinical changes.
Other Name: HQACM

Detailed Description:

Intervention: Weekly patient self-testing (PST) of prothrombin time by international normalized ratio (PT INR) versus conventional monthly high quality anticoagulation management (HQACM) from an anticoagulation clinic with a minimum two years follow-up.

Primary Hypothesis: Compared to conventional monitoring in the clinic, PST of anticoagulation intensity will decrease the number of events of thromboembolism (strokes), bleeding, and all cause deaths and improve the quality of anticoagulation.

Second Hypothesis: PST and conventional monitoring will be comparable in terms of health care utilization and cost.

Primary Outcomes: Event rates (thromboembolism or bleeding episodes), time to first event, time within therapeutic range for anticoagulation intensity, and total health care cost (including price of PST monitors) and utilization.

Study Abstract: Since home monitors of prothrombin time (PT) may potentially improve the safety, quality, and convenience of chronic anticoagulation management, it is likely that there will be demands from providers, patients, and manufacturers to make home monitors available to VA patients. The rationale for PST is that it would permit more intense monitoring and increased patient participation in his/her own care, resulting in increased precision in anticoagulation control and thus fewer events.

Original plan was for a study at 32 sites with a total sample size of about 3,200 patients and a length of three years (one for recruitment and two years of follow-up). Final status was 28 sites that randomized 2922 patients in 2.75 years of recruitment with a minimum of two years of follow-up.

  Eligibility

Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

To be enrolled in this study, patients must:

  1. have AF and/or a MHV;
  2. be scheduled to receive warfarin indefinitely (operationally defined as 2 years);
  3. be using warfarin according to the criteria described in the Coumadin package insert (no off-label uses);
  4. be expected to survive for the duration of the study;
  5. not be suffering from intracranial bleeding (intracranial hemorrhage, subarachnoid hemorrhage, hemorrhagic stroke) or any other contraindication described in the Coumadin package insert;
  6. be willing to perform PST;
  7. be willing to be randomized;
  8. possess adequate cognitive and language skills to follow the protocol and all related instructions;
  9. be willing to participate for the full duration of the study;
  10. sign the informed consent form; and
  11. not be enrolled in another randomized clinical trial that involves a drug or device intervention.

Exclusion Criteria:

Patients are excluded in this study if:

  1. subject has had intracranial hemorrhage, subarachnoid hemorrhage, hemorrhagic stroke, or any other absolute/major contraindication described in the warfarin package insert within the last month
  2. subject enrolled in another randomized clinical trial that involves a drug or device intervention
  3. subject is not able to follow the protocol and all related instructions, and does not have a caregiver with these skills
  Contacts and Locations
Please refer to this study by its ClinicalTrials.gov identifier: NCT00032591

  Show 29 Study Locations
Sponsors and Collaborators
Investigators
Study Chair: David B. Matchar, MD Durham VA Medical Center HSR&D COE
  More Information

Publications:
Responsible Party: Department of Veterans Affairs
ClinicalTrials.gov Identifier: NCT00032591     History of Changes
Other Study ID Numbers: 481
Study First Received: March 27, 2002
Results First Received: June 12, 2013
Last Updated: March 18, 2014
Health Authority: United States: Federal Government

Keywords provided by Department of Veterans Affairs:
AF
Mechanical heart valve (MHV)

Additional relevant MeSH terms:
Atrial Fibrillation
Arrhythmias, Cardiac
Heart Diseases
Cardiovascular Diseases
Pathologic Processes
Thrombin
Hemostatics
Coagulants
Hematologic Agents
Therapeutic Uses
Pharmacologic Actions

ClinicalTrials.gov processed this record on April 17, 2014