Self-Monitoring of Oral Anticoagulation: Systemic Review and Meta-Analysis of Individual Patient Data

Study Questions:

Does self-monitoring affect outcomes in patients anticoagulated with a vitamin K antagonist (VKA)?

Methods:

This was a meta-analysis of 11 randomized trials that compared self-monitoring (n = 3,266) to conventional monitoring by a physician or anticoagulation clinic (n = 3,151) in patients (mean age 65 years) treated with a VKA. The most common indications for the VKA were atrial fibrillation (AF; 53%) and a mechanical valve (35%). There were 12,800 patient-years of follow-up. Primary outcomes were mortality, major hemorrhage, and thromboembolic events.

Results:

Compared to conventional monitoring, self-monitoring was associated with a 49% reduction in the risk of a thromboembolic event. The largest benefit of self-monitoring was observed in patients younger than 55 years old with a mechanical valve. There were no significant differences in mortality or major hemorrhagic events between the self-monitoring and conventional care groups.

Conclusions:

The authors concluded that self-monitoring of anticoagulation status in patients taking a VKA is associated with a reduced risk of thromboembolic events.

Perspective:

Self-monitoring facilitates more frequent testing of the international normalized ratio, presumably resulting in more frequent dose adjustments and a larger proportion of time-in-therapeutic range. Self-monitoring requires a compliant patient who can be adequately trained and a physician who is willing to support self-monitoring. Alternative anticoagulants such as dabigatran and rivaroxaban that have a predictable effect and do not require monitoring now are available for stroke prevention in patients with AF, but are not approved for patients with mechanical valves. Based on this meta-analysis, it appears to be the latter group of patients that benefit the most from self-monitoring. Therefore, efforts to institute self-monitoring should focus on patients with mechanical valves, particularly those younger than 55 years old.

Clinical Topics: Anticoagulation Management, Novel Agents

Keywords: Cooperative Behavior, Vitamin K, Stroke, Follow-Up Studies, Morpholines, International Normalized Ratio, Thromboembolism, Blood Coagulation, beta-Alanine, Benzimidazoles, Hemorrhage, Patient Compliance


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