The Home INR Study (THINRS)
|Atrial Fibrillation||Procedure: Weekly patient self-testing of prothrombin time Other: High quality anticoagulation management (HQACM) with conventional monthly testing||Phase 4|
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
|Official Title:||CSP #481 - The Home INR Study (THINRS)|
- Time to First Event (Death, Stroke, Major Bleed) [ Time Frame: Time to event ]
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 Below is the unpublished cumulative incidence information.
- 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 ]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 ]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 ]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 ]
|Study Start Date:||August 2003|
|Study Completion Date:||May 2008|
|Primary Completion Date:||May 2008 (Final data collection date for primary outcome measure)|
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|
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
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.
Please refer to this study by its ClinicalTrials.gov identifier: NCT00032591
Show 29 Study Locations
|Study Chair:||David B. Matchar, MD||Durham VA Medical Center HSR&D COE|