Clinical Scenario

A patient with recurrent venous thromboembolism is receiving long-term anticoagulation therapy with warfarin (Coumadin). He is concerned about the inconvenience of regular laboratory visits for anticoagulation monitoring and about the long-term safety of warfarin use.

Clinical Question

Can self-monitoring and self-management improve the safety, effectiveness, and feasibility of long-term oral anticoagulation therapy?

Evidence-Based Answer

Self-monitoring and self-management of long-term oral anticoagulation therapy reduce the risks of thromboembolism, all-cause mortality, and minor hemorrhage for appropriately selected patients.¹ (Strength of Recommendation = A, based on consistent, good-quality patient-oriented evidence.)

Practice Pointers

The number of patients treated with long-term oral anticoagulation therapy for atrial fibrillation, heart valve replacement, or venous thromboembolism continues to increase. Warfarin is the most commonly used oral anticoagulant, but monitoring anticoagulation intensity with regular International Normalized Ratio (INR) testing is required. An INR less than 2 is associated with an increased risk of thromboembolism, whereas an INR greater than 4.5 is associated with an increased risk of hemorrhage. The amount of time a patient spends within the therapeutic INR target range depends on the frequency of anticoagulation monitoring.²

A 2006 meta-analysis of 14 randomized controlled trials found that self-monitored anticoagulation therapy reduced thromboembolic events, all-cause mortality, and major hemorrhage. However, when patients self-monitored and self-managed anticoagulation therapy, there were reductions in thromboembolic events and death, but not in major hemorrhage.³ This Cochrane review updates the evidence for self-monitoring and self-management of anticoagulation therapy by including trials published since the 2006 meta-analysis.

In this review, thromboembolic events were reduced in patients who self-monitored their anticoagulation therapy (risk ratio [RR] = 0.57), but were further reduced in patients who self-monitored and adjusted their anticoagulation therapy based on self-monitoring (RR = 0.47). Patients who self-monitored and self-managed also had a reduced risk of all-cause mortality (RR = 0.64). Major hemorrhage (e.g., hemorrhage requiring hospital admission or transfusion) was reduced in trials of self-monitoring, but was not reduced in trials of self-management. Minor hemorrhage (e.g., bleeding after minor trauma, nosebleed) was reduced with self-monitoring and with self-management. The percentage of time spent within the therapeutic target range was not measured consistently, but several trials showed that the time was increased in patients using self-monitoring and self-management. Comparisons of outcomes between standard care and self-monitoring and self-management of anticoagulation therapy are listed in Table 1.¹

Three studies in the review found improved patient satisfaction with self-monitoring and self-management. A trial comparing patients' feelings between the two approaches demonstrated improved satisfaction with self-monitoring compared with self-management. However, an average of 68 percent (range = 31 to 88 percent) of patients considered for participation in these trials did not take part in self-monitoring or self-management. Reasons for not participating included device problems, physical limitations, and problems attending or completing the initial assessment for trial participation.¹

A study of a primary care population found that patients who self-managed anticoagulation therapy perceived greater self-efficacy compared with patients receiving routine care, and that self-management was not associated with increased anxiety.⁴

Point-of-care devices for testing INR have been available since the 1980s. The International Self-Monitoring Association of Oral Anticoagulated Patients estimated that approximately 250,000 patients worldwide monitored or managed their own anticoagulation therapy in 2008.⁵ Before 2008, Medicare coverage for home INR testing applied only to patients with mechanical heart valves. In 2008, coverage of home INR testing was expanded to include patients with chronic atrial fibrillation or venous thromboembolism. Requirements for Medicare coverage include receiving anticoagulation therapy for at least three months before use of the home INR device, and participating in a face-to-face educational program on anticoagulation management.⁶

This Cochrane review confirms previous findings that self-monitoring and self-management can reduce the risk of thromboembolism and death in patients taking oral anticoagulants, and provides supportive evidence that these approaches also reduce minor hemorrhage. Evidence also suggests that patients prefer these approaches to standard care. Although not all patients are eligible for these methods, evidence suggests that they can reduce risks and increase benefits in patients who are motivated and willing to be trained. Resources on anticoagulation management for physicians and patients are provided in Table 2.