Recommendations for patients undertaking self management of oral anticoagulation
BMJ 2001; 323 doi: https://doi.org/10.1136/bmj.323.7319.985 (Published 27 October 2001) Cite this as: BMJ 2001;323:985Data supplement
Summary of studies included in the literature review
A review of the evidence for self management of oral anticoagulation by patients
The move towards self management of oral anticoagulation by patients has grown out of problems inherent to clinic models with patients demanding more autonomy and control over their condition.[1] Although convenience and patient autonomy are undoubtedly important, the clinical safety and effectiveness of self management by patients compared with that from existing models of care must be established before recommendations can be made regarding its wider implementation.
We analysed papers presenting original data for patients undertaking self monitoring that were identified from a computerised literature search on the medical database Medline between 1965 and May 1999 (using a variety of search terms) and by contacting experts in the field. Because of the relative lack of research in this area, observational data have been included alongside controlled trials. From published data, two prospective randomised controlled trials,[2] [3] two matched controlled trials,[4] [5] and three observational studies[6][7][8] were identified. One unpublished randomised controlled trial has been included, although it has not yet been published in detail, because it has been presented at several scientific meetings and contributes to the evidence.[9] This review outlines these studies, focusing particularly on patient selection and education as well as the outcomes of the studies.
Early studies addressed the feasibility of allowing patients receiving oral anticoagulation to undertake self management and were predominantly undertaken in North America.[2] [5] [6] [10]
White et al’s study in the 1980s randomised 46 patients to home monitoring or clinic management.[2] Patients were required to be starting warfarin for the first time, have an indication requiring at least eight weeks of treatment (the duration of follow up), have access to a telephone, live within 150 miles of the study centre (Sacramento, CA), be willing, and have given informed consent. The training process is not adequately described, but it included at least one observation of the patients successfully determining their prothrombin times using the Coumatrack (Dupont; Wilmington, DE).[11] The self monitoring group showed a greater percentage of time within therapeutic range (93% v 75%, P=0.003), with control patients spending significantly more time below range (data not given, P<0.001).
Sawicki’s randomised controlled trial of self management by patients versus routine care showed modest improvements in the self management group in terms of deviation from target international normalised ratio (squared international normalised ratio deviation 0.65 v 0.83, P=0.03).[2] This German study randomised 179 patients, with follow up for six months. All consecutive patients who had not previously been treated within the study centres, who required lifelong anticoagulation, and who agreed to participate were enrolled. The intervention comprised a structured educational programme consisting of three consecutive weekly teaching sessions of 60-90 minutes provided by trained nurses or physicians for groups of three to six patients. The coagulometer used was the Coaguchek (Roche Diagnostics, Mannheim).[12] The international normalised ratio of control patients was estimated every two weeks, and intervention patients were advised to check it every one or two weeks depending on the previous result. Unfortunately, neither group performed particularly well, with only around 50% of patients achieving international normalised ratios within the therapeutic range. Adverse events were similar in both groups—one major haemorrhage in each group and one ischaemic stroke in the routine care group. This is not surprising given the small scale and short period of follow up (three months).
Hasenkam and colleagues enrolled 21 patients after heart valve replacement. Inclusion criteria were implantation of a bileaflet mechanical heart valve, age between 18 and 70 years, and residence within 100 km of the study centre (Aarhus, Denmark), with a high level of patient compliance anticipated from interview.[4] Exclusions were coagulopathies, addiction to drugs or alcohol, and liver disease. The control group (n=20) was matched retrospectively. The Coaguchek was used to estimate international normalised ratios. Training for intervention patients took place over six weeks on an inpatient and outpatient basis. The content and intensity of the training is not specified. Patients were considered to be fully capable of self management after 30 weeks. Overall, 19/21 patients continued self management beyond nine months (the minimum duration of follow up). The median international normalised ratio was within therapeutic range for all intervention patients, but for only 15/20 controls. The intervention patients were within therapeutic range 77% of the time compared with 55% for the control patients.
In a similar study, Ansell et al in North America recruited 20 patients with stable international normalised ratios (undefined) who had been taking oral anticoagulation for at least one month and were willing to undertake self monitoring.[5] Training in both monitoring and dose adjustment took place over a two week period; however, the content and intensity of training are not specified. The study used the Coumatrak monitor. Study patients monitored their prothrombin time 2153 times during a mean interval of 44.7 months compared with 1608 measurements over 42.5 months in the 20 matched controls. Study patients had therapeutic prothrombin times 88.6% of the time compared with 68.0% for the controls. Complication rates did not differ significantly between the groups.
Anderson et al reported on 40 patients receiving long term warfarin therapy who were willing to undertake self monitoring.[6] The selection process and training are not well described. The coagulometer used was a Biotrak PrimeTime Monitor 1000 (Biotrak, Mountain View, CA). Patients were followed for 6-24 months and showed good therapeutic control, although the outcomes stated are principally related to agreement between international normalised ratio measured by the patient and a contemporaneous international normalised ratio measured by a laboratory.
Barnado reported on patients who had been trained in self monitoring using Coaguchek between 1986 and 1992.[7] The training programme consisted of three sessions of one hour with a nurse to learn how to use the coagulometer, with an additional five hours of theoretical training with a doctor. Eligibility criteria were the ability to participate in a patient orientated programme (not defined), adequate eyesight (not defined), adequate motor coordination (not defined), and sufficient manual dexterity to comply with all aspects of the self management programme (not defined). Overall, 83.1% of prothrombin time determinations were within the target range, with no major bleeding or thrombotic episodes reported. One major weakness of this study was the poor level of follow up, with only 216 out of 600 patients reported.
Massicotte and colleagues in Canada reported on 23 children who undertook home testing using a Biotrak, with testing performed by their parents.[8] This was essentially a feasibility study, but it showed that 377 of 599 home measurements, 62.9% were within the therapeutic range. This is stated to be similar to patients managed in a clinic, but the original data are not given. The average duration of follow up was 13 months. One subdural haematoma and one catheter related thrombotic event were reported.
The early self controlled anticoagulation trial (ESCAT) from Germany has reported interim data on 582 patients, with 279 using near patient testing (Coaguchek Plus, Roche Diagnostics, Mannheim) to perform self management following heart valve replacement and 303 managed by a doctor.[9] It is not clear whether the control group was managed within specific clinics or at their doctor’s office. Patients in the self management group were given standardised training in home prothrombin estimation using near patient testing and asked to monitor their international normalised ratio every third day. Patients were asked to inform their doctor if the international normalised ratio was 0.5 below or above the target range. The physicians managed the control group without recommendations for an interval between measuring international normalised ratios. In total, 15 300 readings were analysed for the self management group compared with only 8400 for the conventionally managed patients. Overall, 80% of international normalised ratios in the self managed patients were within therapeutic range compared with 54% from the control group. Of the patients randomised to self management, 8.3% withdrew. The authors concluded that 80% of patients with mechanical cardiac valves could undertake self monitoring of international normalised ratio.
While self management seems to be a credible alternative to existing models of care, there are currently no data from the United Kingdom and no clinical outcome data in any of the published studies to support its use. Evidence regarding clinical and cost effectiveness is required from British trials before self management of oral anticoagulation by patients can be introduced on a wide scale in the United Kingdom.
The main criticism of studies published to date is that standard care within them was poor compared with published data from the United Kingdom.[13][14][15] This means that any improvement in therapeutic control, and related reductions in serious adverse events, associated with self management will be exaggerated compared with British models of care. Until data from the United Kingdom are available from randomised controlled trials in which patients eligible for self management are allocated to intervention or routine care groups, caution must be applied in allowing patients to undertake patient self management.
Issues that still need to be addressed are the definition of patient eligibility for self monitoring, the question of the optimal frequency of testing required, and the nature of the training required for patients. None of these studies seem to have considered whether the patient should regularly use some form of external quality control to test the reliability of their international normalised ratio results.
Costs
The cost effectiveness of self management by patients needs further investigation. One American study that investigated cost was identified.[6] The cost of home monitoring was approximately half that of routine care over an eight week period with costs based only on the cost of monitor and test cartridges against hospital laboratory tests. Other costs such as transport for the patient and clinic overheads were not included. The authors stated that if improved control reduced the risk of thromboembolic or haemorrhagic complications, the cost savings associated with home monitoring would be substantial.
One German study showed a 50% reduction in costs associated with self management compared with routine care.[16] Routine care consisted of attendance at the doctor’s office; control was poor and rates of complications, which were included in the analysis, were high.
From the British perspective, comparison with hospital clinic attendance must be considered. Based on the data from the European and American studies, given the capital costs and frequency of testing associated with self management, we calculate that the costs of self management could be up to five times higher than those associated with routine hospital care. This level of increase in the cost of service provision could only be recouped within the NHS by reductions in the overall frequency of serious adverse events, particularly stroke.
- Kurnitz J. The view from the inside: personal reflections. J Thromb Thrombolysis 1998;5:S49-51.
- Sawicki PT. A structured teaching and self-management program for patients receiving oral anticoagulation. A randomized controlled trial. JAMA 1999;281:145-50.
- White R, McCurdy SA , von Marensdorff H, Woodruff DE, Leftgoff PA. Home prothrombin time monitoring after the initiation of warfarin therapy. Ann Intern Med 1989;111:730-6.
- Hasenkam JM, Kimose HH, Knudsen L, Gronnesby H, Halborg J, Christensen TD, et al. Self management of oral anticoagulation therapy after heart valve replacement. Eur J Cardiothorac Surg 1997;11:935-42.
- Ansell JE, Patel N, Ostrovsky D, Nozzolillo E, Peterson AM. Long term patient self management of oral anticoagulation. Arch Intern Med 1995;155:2185-9.
- Anderson DR, Harrison L, Hirsh J. Evaluation of a portable prothrombin time monitor for home use by patients who require long-term oral anticoagulant therapy. Arch Intern Med 1993;153:1441-7.
- Barnado A. Experience with patient self-management of oral anticoagulation. J Thromb Thrombolysis 1995;2:321-5.
- Massicotte P, Marzinotto V, Vegh P, Adams M, Andrew M. Home monitoring of warfarin therapy in children with a whole blood monitor. J Pediatr 1995;127:389-94.
- Korfer R, Kortke H. ESCAT Early Self Controlled Anticoagulation Trial. Ann Thorac Surg (in press).
- Hasenkam JM, Knudsen L, Kimose HH, Gronnesby H, Atterman J, Anderson NT, et al. Practicability of patient self testing of oral anticoagulant therapy by the international normalized ratio (INR) using a portable whole blood monitor. Thromb Res 1997;85:77-82.
- Lucas FV, Duncan A, Jay R, Coleman R, Craft P, Chan B, et al. A novel whole blood capillary technic for measuring the prothrombin time. Am J Clin Path 1987;88:442-6.
- Van den Besselar AMHP, Breddin K, Lutze G, Parker-Williams J, Taborski U, Vogel G, et al. Multicenter evaluation of a new capillary blood prothrombin time monitoring system. Blood Coagul Fibrinolysis 1995;6:726-32.
- Baglin T. Decentralised anticoagulant care. Clin Lab Haematol 1994;16:327-9.
- Rose P. Audit of anticoagulant therapy. J Clin Pathol 1996;49:5-9.
- Fitzmaurice DA, Hobbs FDR, Murray ET, Bradley CP, Holder R. Evaluation of computerised decision support for oral anticoagulation management based in primary care. Br J Gen Pract 1996;46:533-5.
- Taborski VWE, Wittstamm FJ, Bernada A. Cost-effectiveness of self-management anticoagulant therapy in Germany. Semin Thromb Haemost 1999;25:103-7.
Table A Summary of studies included in the literature review
Study
Country
Study type
No of patients Results
Receiving intervention Acting as controls Value determined Intervention group (%) Control group (%) Sawicki 19992 Germany Randomised controlled 90 89 Patients in range
53 34 White et al 19893 United States Randomised controlled 23 23 Time in range 93 75 Hasenkam et al 19974 Denmark Matched 21 20 Time in range 77 55 Ansell et al 19955 United States Matched 20 20 Time in range 89 68 Anderson et al 19936 Canada Observational 40 NA Tests in range 74 NA Barnado 19957 Germany Observational 216 NA Tests in range 83 NA Massicotte et al 19958 Canada Observational 23 NA Tests in range 63 NA Korfer and Kortke (in press)9 Germany Randomised controlled 279 303 Tests in range 80 75 NA=not applicable.
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