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Comparing Self-Management of Oral Anticoagulant Therapy with Clinic Management

Background: Some believe that oral anticoagulation control can be improved with patient self-management.

Objective: To determine the effectiveness of patient self-management of oral anticoagulation compared to standard clinic management.

Methods: This was a randomized, controlled study set in an anticoagulation clinic at a hospital in Spain. Patients were selected from the anticoagulation clinic population of 5000 patients. Patients were eligible for the study if they were over 18 years old and had been receiving anticoagulation for a minimum of 3 months prior to initiation of the study. Patients younger than 18 years of age and those who had a mental or physical disability without a competent caregiver were excluded. 1500 patients were randomly selected and 1233 of them were interviewed. 737 patients started the study with 368 patients in the self-management group and 369 in the clinic group. Acenocoumarol was the drug utilized and doses were tailored from patient to patient according to the INR. Patients in the clinic were managed according to the clinic protocol and self-management patients were trained to use a coagulometer and titrate their dose accordingly. The patients were observed for a median of 11.8 months (range of 0.3 to 16.9 months). The primary outcomes included percentage of INR values within the desired range and the percentage of time within the target range. The distance from the target range was also measured as a primary outcome. Secondary outcomes dealt with safety and included thromboembolic and hemorrhagic events. Minor bleeding was also reported. The power of the study was 90%. Results were analyzed both on an intent to treat and on on-treatment analysis.

Results: A total of 649 (88%) patients completed the study. 289 of the 368 (79%) patients in the self-management group finished the study and 360 of the 369 (98%) patients in the clinic group finished the study. Results were reported for all patients and also broken down by target INR values. The self-management group had a higher percentage of INR values in the target range according to the intent to treat analysis (58.6 vs. 55.6) [95% CI for difference, 0.4% to 5.4%] (p=0.02). The actual time spent inside the target range and the distance from the target range were not found to be significant. For individual target ranges, % differences in the INR values within the target range were significant only in the 2.5-3.5 range in both the intent to treat and the on-treatment groups (p=0.03 and 0.02 respectively) favoring the self management group. 27 patients in the clinic management group had major complications compared to 8 patients in the self-management group. There was a 5.1% difference in major complications in favor of the self-management group [95% CI, 1.7 to 8.5%]. The self-management group also had lower rates of minor hemorrhage and death. The authors concluded that self-management of anticoagulation was similar to clinic management. It was also concluded that complications were less frequent in the self-management group.

Strengths: The study was a randomized trial that included a substantial amount of patients. The study had a variety of patients enrolled with different indications and target ranges. The patients also had to undergo a standard education program and were given standardized dosing protocols.

Weaknesses: The study was done at a single site and was unblinded. The authors alluded to a high dropout rate in one of the groups. The number of tests to assess INR was substantially different between the two groups.

Conclusion: The results of this study could be used in oral anticoagulation therapy. Some, but not all, patients who receive oral anticoagulation may be candidates for self-management for their therapy under the supervision of a clinical specialist. However, some patients, in this study and in the general population, may not feel comfortable with managing their oral anticoagulation therapy. A more balanced study in regards to number of test results could further validate the use of self-testing. This practice of self-testing could prove very beneficial in a selected number of patients.

Menendez-Jandula B, Souto JC, Oliver A, Monttserrat I, Quintana M, Gich I, et al. Comparing Self-Management of Oral Anticoagulant Therapy with Clinic Management. Ann Intern Med 2005 Jan 4; 142(1): 1-10.

Tim Miller, Doctor of Pharmacy Candidate