Patient Self-Testing/Management May Decrease Mortality and Thromboembolic Events among Patients on Long-Term Anticoagulation
Anticoagulation with Vitamin K antagonists (e.g., warfarin) reduces thromboembolic complications in patients with common chronic conditions, including atrial fibrillation. However, Vitamin K antagonists have a narrow therapeutic window that requires frequent monitoring, thus anticoagulation clinics were developed to streamline and standardize care. With the recent advent of reliable and accurate portable monitoring devices, testing and dose adjustment can be done by patients in the home. This evidence review sought to determine whether patient self-testing (PST), either alone or in combination with self-dose adjustment (patient self-management, PSM), is associated with fewer thromboembolic complications and all-cause mortality – without an increase in major bleeding – compared to usual care. Investigators reviewed studies published between 1966 and 10/10, identifying 22 trials that compared PST or PSM with care in a physician’s office or an anticoagulation clinic in more than 8,400 patients who received oral anticoagulation therapy for more than three months.
- Compared to usual care, PST with or without PSM is associated with significantly fewer deaths and thromboembolic events – without increased risk of serious bleeding – for a highly select group of motivated adult patients requiring long-term anticoagulation with Vitamin K antagonists.
- Patients randomized to PST/PSM had a 26% lower risk of death and a 42% reduction in major thromboembolism without any increased risk of major bleeding events.
- Whether or not this care model is cost-effective and can be implemented successfully in typical U.S. healthcare settings requires further study.
- The evidence was judged to be of moderate strength for thromboembolism and bleeding, but of low strength for mortality due to the inconsistency among studies. The inconsistency was largely explained by one study (The Home INR Study or THINRS).
- The meta-analysis conclusions may not apply to VA, where quality of anticoagulation clinic care is high. In THINRS, the most recent and largest trial to date and only VA study, weekly self-testing did not reduce time to first stroke, major bleed, or death compared to monthly testing in clinic. Home testing did, however, slightly increase quality of life and satisfaction with anticoagulation therapy.
- Only five of the trials assessed in this study were considered high quality, and only two of the studies were conducted in the U.S..
- Current data do not address whether PST or PSM is safe during the high-risk initiation phase of anticoagulation.
This study was funded through HSR&D. Drs. Bloomfield, Greer, and Wilt are members of VA’s Evidence Synthesis Program at HSR&D’s Center for Chronic Disease Outcomes Research, Minneapolis, MN.
Bloomfield H, Krause A, Greer N,…Wilt T. Systematic Review and Meta-Analysis: Effect of Patient Self-Testing and Self-Management of Chronic Anticoagulation on Major Clinical Outcomes. Annals of Internal Medicine April 5, 2011;154(7):472-82.