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Self-Management of Oral Anticoagulation
Jack Ansell, M.D., Boston University Medical Center
Review: Menendez-Jandula B, Souto JC, Oliver A, Montserrat I, Quintana M, Gich I, Bonfill X, Fontcuberta J. Comparing self-management of oral anticoagulant therapy with clinic management: a randomized trial. Ann Intern Med. 2005 Jan 4;142(1):1-10.
Oral anticoagulation with warfarin (brand Coumadin) is a common medication with over 2 million individuals receiving therapy in the US for such conditions as venous thrombosis of the lower extremities or atrial fibrillation. Oral anticoagulation is associated with a high complication rate if not managed well. Good management requires keeping the patient in a narrow therapeutic International Normalized Ratio (INR) range. Because of the intensity of dose management, anticoagulation clinics have developed to help physicians. Focused anticoagulation clinic management has been shown to improve outcomes compared to the routine management provided by physicians 1,2, but estimates suggest that less than 50% of patients in the United States on oral anticoagulants are managed by such clinics. Point-of-care prothrombin time monitoring technology, developed in the late 1980s, allows for fingerstick INR monitoring and patient self-testing. Using POC devices, patients may either monitor their own INR at home and receive dose-adjustment guidelines from their physician, or actually adjust their own anticoagulation dose after proper training 1. A body of evidence suggests that this type of care achieves outcomes significantly better than routine care by individual physicians, but only slightly better than focused care delivered by an anticoagulation clinic 2,3.
Menendez-Jandula, et al. have compared traditional anticoagulation management as it is delivered in Spain (by hematologists in special clinics equivalent to anticoagulation clinics in the US) with patient self-management guided by patient self-testing using a POC device. In this randomized unblinded trial, 368 patients managed their own therapy after training, and outcomes over the next 12 months were compared to 369 patients managed by an anticoagulation clinic. The investigators measured the percent of INRs or time in therapeutic range as the primary outcome, and frequency of major hemorrhage or thromboembolism as the secondary outcome. Although the difference between groups for percent or time in range was small, the self-management group experienced significantly fewer major adverse events (2.2%) compared to the anticoagulation clinic group (7.3%), the difference being attributable primarily to fewer thromboembolic events. There were also significantly fewer minor bleeding events. The high dropout rate in the self-management group suggests that this type of care is not suitable for all anticoagulated patients.
This study, with its large patient base, further supports the self-management model of anticoagulation care. Its results are consistent with a number of other, often smaller, trials. However, self-management may not be suitable for all patients. It requires a reliable patient who is willing and able to test his/her own INR and manage his/her dose. It requires suitable training. Lastly, it requires a physician or anticoagulation clinic willing to oversee such therapy. Patient self-management has not taken hold in the United States compared to its greater use in other countries 4. A major barrier is limitation of reimbursement to only patients with mechanical heart valves, as well as a complicated reimbursement scheme to implement therapy. Several fears of physicians include concerns about liability for untoward events, about instrument accuracy, and possibly, a low level of awareness that such therapy is available. Further studies such as this one, or an ongoing study being conducted by the Veterans Administration Medical Centers should help to popularize this model of care, and perhaps convince third party funding agencies that it is in their best interests to provide reimbursement mechanisms to facilitate such care.
1. Ansell JE, Hughes R. Evolving models of warfarin management: Anticoagulation clinics, patient self-monitoring, and patient self-management. Amer Heart J 1996;132:1095-1100.
2. Ansell J, Hirsh J, Poller L, Bussey H, Jacobson A, Hylek E. The pharmacology and management of the vitamin K antagonists. Chest 2004;126(Suppl):202S-231S.
3. Siebenhofer A, Berghold A, Sawicki PT. Systematic review of studies of self-management of oral anticoagulation. Thromb Haemost 2004;91:225-232.
4. Jacobson AK. The North American experience with patient self-testing of the INR. Semin Vas Med 2003;3:295-302.
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