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Patient Self-Management of Anticoagulants Reduced Arterial Thromboembolism and Adverse Effects/COMMENTARY

Posted on: Sunday, 24 July 2005, 03:01 CDT

Mnendez-Jndula B, Souto JC, Oliver A, et al. Comparing self- management of oral anticoagulant therapy with clinic management: a randomized trial. Ann Intern Med. 2005;142:1-10. Clinical impact ratings: GIM/FP/GP ******* Hematol/Thrombo *******

QUESTION

Is patient self-management of oral anticoagulants as efficacious and safe as management in an anticoagulation clinic?

METHODS

Design: Randomized controlled trial.

Allocation: Concealed.*

Blinding: Blinded (assessors of complications).*

Follow-up period: Median 11.8 months.

Setting: A hospital in Barcelona, Spain.

Patients: 737 ambulatory patients ≥ 18 years of age who had been receiving long-term anticoagulant therapy for ≥ 3 months. Exclusion criteria were severe physical or mental illness without a responsible caregiver, and inability to understand Spanish. Intervention: Self-management (n = 368) or clinic-based management (n = 369) of oral anticoagulant therapy with acenocoumarol. Self- management comprised a small-group educational program, delivered in two 2-hour sessions by a specially trained nurse. Patients were in- structed on use of a coagulometer, interpretation of international normalized ratios (INRs), and adjustment of doses. They tested their INRs at home once a week using the portable CoaguChek S coagulometer (Roche Diagnostics, Mannheim, Germany) and determined the appropriate anticoagulant dose and time of the next INR test. Clinic- based management comprised patient visits to the hospital every 4 weeks to check INRs (KC 10 coagulometer, Amelung, Lemgo, Germany). A hematologist adjusted the dose and made the next appointment for INR testing.

Outcomes: Percentage of INR values within target range and percentage of time within target range; major bleeding (life- threatening bleeding or bleeding requiring transfusion or hospital admission); minor bleeding; arterial thromboembolism (stroke, arterial embolism, valve thrombosis, or transient ischemic attack); venous thromboembolism (deep venous thrombosis, pulmonary embolism, or superficial thrombophlebitis); and death.

Patient follow-up: 100% (intention-to-treat analysis).

MAIN RESULTS

The self-management group had a higher mean percentage of INR determinations within the target range than did the clinic-based group (58.6% vs 55.6%, mean difference 3.0%, 95% CI 0.4 to 5.4). The groups did not differ for percentage of time within the target range (64.3% vs 64.9%, P = 0.2). The self-management group had a lower rate of minor bleeding, arterial thromboembolism, combined major bleeding or any thromboembolism, and death than did the clinic- based group; the groups did not differ for major bleeding or venous thromboembolism (Table).

Self-management vs clinic-based management of oral anticoagulant therapy[dagger]

CONCLUSION

Patient self-management of oral anticoagulants resulted in similar levels of control and major bleeding and lower rates of arterial thromboembolism and death than clinic-based management. Source of funding: In part, Roche Diagnostic S. L.

For correspondence: Dr. J. C. Souto, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. E-mail jsouto@hsp.santpau.es.

* See Glossary.

COMMENTARY

The study by Mnendez-Jndula and colleagues and a study by Krtke and Krfer (1) are the largest randomized trials on self-management of treatment with vitamin K antagonists. Both studies showed a larger fraction of INR results within the therapeutic range in the treatment group. Mnendez-Jndula and colleagues also assessed "time within therapeutic range" and found it to be similar in the self- management and clinic-based groups. This is easily explained as patients usually self-tested weekly, regardless of whether the INR result was within the therapeutic range. In the clinic-based group, the interval between tests was gradually increased to 4 weeks after acceptable INR results were obtained.

Surprisingly, there were fewer arterial thromboembolic events and minor bleeding episodes with self-management, despite similar time spent within the therapeutic range in the 2 groups. One explanation is the greater compliance, awareness of risk factors for complications, and responsibility of patients in the self- management group. A selection bias may also exist given that 22% of patients randomized to self-management withdrew early.

The incidence of thromboembolic complications in the clinic- based group was high (5.4%), albeit similar to what the authors found in their review of other studies. Most patients in the study of Mnendez-Jndula had atrial fibrillation, and these patients may have been at high risk for stroke because of concomitant risk factors. However, Krtke and Krfer (1) reported only 2.1% of patients with thromboembolic complications, which raises the possibility of suboptimal conventional management. This is problematic given the open design of the study.

Overall, anticoagulation self-monitoring provides INR control that is as good as, or better than, that by a conventional laboratory, is convenient for patients, and may decrease adverse outcomes. Whether self-monitoring is widely used in clinical practice depends on its cost-effectiveness and whether health insurers will cover the costs of self-monitoring devices, which are prohibitive for most patients.

Sam Schulman, MD

McMaster University

Hamilton, Ontario, Canada

Reference

1. Krtke H, Krfer R. AnnThorac Surg. 2001;72:44-8.

Copyright American College of Physicians Jul/Aug 2005

Source: ACP Journal Club

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