Abstract
Seven randomized trials published in the last six years have shown that warfarin reduces the risk of ischaemic strokes and death in patients with atrial fibrillation. The annual rates of major bleeding episodes in all these trials were low and, as a result, doctors in primary and secondary care are being encouraged to consider using warfarin for patients with atrial fibrillation unless there are obvious contraindications. However, the populations used in these studies were highly selected and rigorously monitored throughout the trial period to minimize the risk of bleeding in a way which probably could not be expected in routine primary care. Although the rates of major bleeding episodes were uniformly low, the rates of minor bleeding episodes were much higher and these could impact substantially on patients' views of the treatment and on the workload of the primary care team. Evidence is now at hand which allows the stratification of risk in patients with atrial fibrillation which should enable those who are at greatest risk to be considered for this form of treatment. Patients may develop risk factors over time which could render them unsuitable for continuation of warfarin therapy. The general practitioner is centrally placed to make the decision about initiating or continuing treatment or indeed stopping it. Several models for decision making in warfarin treatment from primary and secondary care are proposed.
Full text
PDFSelected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bath P. M., Prasad A., Brown M. M., MacGregor G. A. Survey of use of anticoagulation in patients with atrial fibrillation. BMJ. 1993 Oct 23;307(6911):1045–1045. doi: 10.1136/bmj.307.6911.1045. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Boysen G. Anticoagulation for atrial fibrillation and stroke prevention. Neuroepidemiology. 1993;12(5):280–284. doi: 10.1159/000110329. [DOI] [PubMed] [Google Scholar]
- Cairns J. A. Stroke prevention in atrial fibrillation trial. Circulation. 1991 Aug;84(2):933–935. doi: 10.1161/01.cir.84.2.933. [DOI] [PubMed] [Google Scholar]
- Connolly S. J., Laupacis A., Gent M., Roberts R. S., Cairns J. A., Joyner C. Canadian Atrial Fibrillation Anticoagulation (CAFA) Study. J Am Coll Cardiol. 1991 Aug;18(2):349–355. doi: 10.1016/0735-1097(91)90585-w. [DOI] [PubMed] [Google Scholar]
- Doble N., Baron J. H. Anticoagulation control with warfarin by junior hospital doctors. J R Soc Med. 1987 Oct;80(10):627–627. doi: 10.1177/014107688708001009. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dow L., Bertagne B. Anticoagulation in patients with atrial fibrillation. Underuse of warfarin is multifactorial. BMJ. 1993 Dec 4;307(6917):1492–1493. doi: 10.1136/bmj.307.6917.1492-a. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ezekowitz M. D., Bridgers S. L., James K. E., Carliner N. H., Colling C. L., Gornick C. C., Krause-Steinrauf H., Kurtzke J. F., Nazarian S. M., Radford M. J. Warfarin in the prevention of stroke associated with nonrheumatic atrial fibrillation. Veterans Affairs Stroke Prevention in Nonrheumatic Atrial Fibrillation Investigators. N Engl J Med. 1992 Nov 12;327(20):1406–1412. doi: 10.1056/NEJM199211123272002. [DOI] [PubMed] [Google Scholar]
- Fihn S. D., McDonell M., Martin D., Henikoff J., Vermes D., Kent D., White R. H. Risk factors for complications of chronic anticoagulation. A multicenter study. Warfarin Optimized Outpatient Follow-up Study Group. Ann Intern Med. 1993 Apr 1;118(7):511–520. doi: 10.7326/0003-4819-118-7-199304010-00005. [DOI] [PubMed] [Google Scholar]
- Forfar J. C. A 7-year analysis of haemorrhage in patients on long-term anticoagulant treatment. Br Heart J. 1979 Aug;42(2):128–132. doi: 10.1136/hrt.42.2.128. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gurwitz J. H., Goldberg R. J., Holden A., Knapic N., Ansell J. Age-related risks of long-term oral anticoagulant therapy. Arch Intern Med. 1988 Aug;148(8):1733–1736. [PubMed] [Google Scholar]
- Gustafsson C., Asplund K., Britton M., Norrving B., Olsson B., Marké L. A. Cost effectiveness of primary stroke prevention in atrial fibrillation: Swedish national perspective. BMJ. 1992 Dec 12;305(6867):1457–1460. doi: 10.1136/bmj.305.6867.1457. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hickish G. Hearing problems of elderly people. BMJ. 1989 Dec 9;299(6713):1415–1416. doi: 10.1136/bmj.299.6713.1415. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hull R., Hirsh J., Jay R., Carter C., England C., Gent M., Turpie A. G., McLoughlin D., Dodd P., Thomas M. Different intensities of oral anticoagulant therapy in the treatment of proximal-vein thrombosis. N Engl J Med. 1982 Dec 30;307(27):1676–1681. doi: 10.1056/NEJM198212303072704. [DOI] [PubMed] [Google Scholar]
- King D., Davies K. N. Anticoagulation in patients with atrial fibrillation. Doctors reluctant despite evidence. BMJ. 1993 Dec 4;307(6917):1494–1494. doi: 10.1136/bmj.307.6917.1494. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kumar S., Haigh J. R., Rhodes L. E., Peaker S., Davies J. A., Roberts B. E., Feely M. P. Poor compliance is a major factor in unstable outpatient control of anticoagulant therapy. Thromb Haemost. 1989 Sep 29;62(2):729–732. [PubMed] [Google Scholar]
- Lancaster T. R., Singer D. E., Sheehan M. A., Oertel L. B., Maraventano S. W., Hughes R. A., Kistler J. P. The impact of long-term warfarin therapy on quality of life. Evidence from a randomized trial. Boston Area Anticoagulation Trial for Atrial Fibrillation Investigators. Arch Intern Med. 1991 Oct;151(10):1944–1949. [PubMed] [Google Scholar]
- Landefeld C. S., Beyth R. J. Anticoagulant-related bleeding: clinical epidemiology, prediction, and prevention. Am J Med. 1993 Sep;95(3):315–328. doi: 10.1016/0002-9343(93)90285-w. [DOI] [PubMed] [Google Scholar]
- Laupacis A. Anticoagulants for atrial fibrillation. Lancet. 1993 Nov 20;342(8882):1251–1252. doi: 10.1016/0140-6736(93)92353-u. [DOI] [PubMed] [Google Scholar]
- Lowe G. D. Antithrombotic treatment and atrial fibrillation. BMJ. 1992 Dec 12;305(6867):1445–1446. doi: 10.1136/bmj.305.6867.1445. [DOI] [PMC free article] [PubMed] [Google Scholar]
- O'Connell J. E., Gray C. S. Anticoagulation in patients with atrial fibrillation. Use of warfarin dependent on local services. BMJ. 1993 Dec 4;307(6917):1493–1493. doi: 10.1136/bmj.307.6917.1493-b. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Owen M., Liddell M., McGuffin P. Alzheimer's disease. BMJ. 1994 Mar 12;308(6930):672–673. doi: 10.1136/bmj.308.6930.672. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pell J. P., McIver B., Stuart P., Malone D. N., Alcock J. Comparison of anticoagulant control among patients attending general practice and a hospital anticoagulant clinic. Br J Gen Pract. 1993 Apr;43(369):152–154. [PMC free article] [PubMed] [Google Scholar]
- Petersen P., Boysen G., Godtfredsen J., Andersen E. D., Andersen B. Placebo-controlled, randomised trial of warfarin and aspirin for prevention of thromboembolic complications in chronic atrial fibrillation. The Copenhagen AFASAK study. Lancet. 1989 Jan 28;1(8631):175–179. doi: 10.1016/s0140-6736(89)91200-2. [DOI] [PubMed] [Google Scholar]
- Petitti D. B., Strom B. L., Melmon K. L. Duration of warfarin anticoagulant therapy and the probabilities of recurrent thromboembolism and hemorrhage. Am J Med. 1986 Aug;81(2):255–259. doi: 10.1016/0002-9343(86)90260-3. [DOI] [PubMed] [Google Scholar]
- Rassam S. M. Anticoagulation in patients with atrial fibrillation. Not safe and not cheap. BMJ. 1993 Dec 4;307(6917):1492–1492. doi: 10.1136/bmj.307.6917.1492. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tan G. B., Cohen H., Taylor F. C., Gabbay J. Referral of patients to an anticoagulant clinic: implications for better management. Qual Health Care. 1993 Jun;2(2):96–99. doi: 10.1136/qshc.2.2.96. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Taylor F., Ramsay M., Voke J., Cohen H. Anticoagulation in patients with atrial fibrillation. GPs not prepared for monitoring anticoagulation. BMJ. 1993 Dec 4;307(6917):1493–1493. doi: 10.1136/bmj.307.6917.1493. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Turpie A. G., Gunstensen J., Hirsh J., Nelson H., Gent M. Randomised comparison of two intensities of oral anticoagulant therapy after tissue heart valve replacement. Lancet. 1988 Jun 4;1(8597):1242–1245. doi: 10.1016/s0140-6736(88)92070-3. [DOI] [PubMed] [Google Scholar]
- White H. D. Aspirin or warfarin for non-rheumatic atrial fibrillation? Lancet. 1994 Mar 19;343(8899):683–684. doi: 10.1016/s0140-6736(94)91573-3. [DOI] [PubMed] [Google Scholar]
- Wickramasinghe L. S., Basu S. K., Bansal S. K. Long-term oral anticoagulant therapy in elderly patients. Age Ageing. 1988 Nov;17(6):388–396. doi: 10.1093/ageing/17.6.388. [DOI] [PubMed] [Google Scholar]