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Therapeutics

Patient self-management of anticoagulants reduced arterial thromboembolism and adverse effects

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ACP J Club. 2005 Jul-Aug;143:8. doi:10.7326/ACPJC-2005-143-1-008


Clinical Impact Ratings

GIM/FP/GP: 5 stars

Hematol/Thrombo: 6 stars


Source Citation

Ménendez-Jándula 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. [PubMed ID: 15630104]


Abstract

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 instructed 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).

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.

*See Glossary.

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.


Table. Self-management vs clinic-based management of oral anticoagulant therapy†

Outcomes at median 11.8 mo Self Clinic-based RRR (95% CI) NNT (CI)
Major bleeding 1.1% 1.9% 43% (−82 to 82) Not significant
Minor bleeding 15% 36% 59% (46 to 69) 5 (4 to 7)
Arterial thromboembolism 0.8%‡ 4.6%‡ 82% (44 to 94) 27 (16 to 63)
Venous thromboembolism 0.3%‡ 1.4%‡ 80% (−29 to 97) Not significant
Major bleeding or any thromboembolism 2.2% 7.3% 70% (37 to 86) 20 (12 to 46)
Death 1.6% 4.1% 60% (1 to 84) 41 (20 to 2994)

†Abbreviations defined in Glossary; RRR, NNT, and CI calculated from data in article.
‡Calculated from data in article.


Commentary

The study by Ménendez-Jándula and colleagues and a study by Körtke and Körfer (1) are the largest randomized clinical 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. Ménendez-Jándula 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 Ménendez-Jándula had atrial fibrillation, and these patients may have been at high risk for stroke because of concomitant risk factors. However, Körtke and Körfer (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. Körtke H, Körfer R. International normalized ratio self-management after mechanical heart valve replacement: is an early start advantageous? Ann Thorac Surg. 2001;72:44-8. [PubMed ID: 11465228]