The Home INR Study "THINRS"

Completed

Phase 4 Results

Trial Description

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.

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.

Conditions

Interventions

  • Weekly patient self-testing of prothrombin time Procedure
    ARM 1: Kind: Experimental
    Label: 1
    Description: Patient Self-Testing (PST) of prothrombin time by international normalized ratio (PT-INR or INR) with weekly testing
    ARM 2: Kind: Experimental
    Label: Arm 1
    Description: Patient Self-Testing (PST) of prothrombin time by international normalized ratio (PT-INR or INR) with weekly testing
  • High quality anticoagulation management (HQACM) with conventional monthly testing Other
    Other Names: HQACM
    Intervention Desc: HQACM with testing every 4 weeks and as indicated for out of range values, medication/clinical changes.
    ARM 1: Kind: Experimental
    Label: 2
    Description: High quality anticoagulation management (HQACM) with conventional monthly testing
    ARM 2: Kind: Experimental
    Label: Arm 2
    Description: High quality anticoagulation management (HQACM) with conventional monthly testing

Trial Design

  • Allocation: Randomized
  • Masking: Open Label
  • Purpose: Treatment
  • Endpoint: Safety/Efficacy Study
  • Intervention: Parallel Assignment

Patient Involvement

Patient will be randomized to one of two arms: 1. 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. or 2. 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.

Outcomes

Type Measure Time Frame Safety Issue
Primary 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.
Primary Time to First Event (Death, Stroke, Major Bleed) Time to event Yes
Secondary Time in Therapeutic Range Over Full Length of Follow-up (0 to 100 Percent) Full length of follow-up; average of 3 years Yes
Secondary DASS at 2 Years of Follow-up At two years of follow-up No
Secondary Cumulative Gain in Health Utilities at 2 Year After 2 years of follow-up for each subject No
Secondary Health Care Costs at 2 Year After 2 years of follow-up for each subject No

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