Because vitamin K antagonists (VKAs) may take up to several days before they reach efficacy, testing INR frequently is mandatory at the onset of treatment:
- Usually daily while hospitalized
- Varies from one practitioner to another in the general practitioner setting
- When the patient is stabilized, the recommended minimum frequency20 is once every:
- 4 weeks (stable patients)
- 2 weeks (less stable patients)
- Weekly: 85% of patients remain in target range when monitoring weekly, whereas only 50% remain in target range when monitoring monthly. Heneghan et al.19
Of course, if testing more frequently means the patient must travel to a clinic or lab, this may put stress on their quality of life including time away from work, restriction on travel, costs for travel. For most patients, testing twice or four times per month is not a feasible option if travel to a lab, clinic or physician’s office is required. Yet many patients can be trained to test at home once per week or twice per month, providing a greater quality of life both medically and personally.
Together with you, the medical professional, properly trained patients and/or caregivers are capable of performing reliable PT testing and even adjusting their medication accordingly3. For these patients, self-testing or self-managing is cost-effective and leads to outcomes at least as good as standard INR testing in a specialized clinic.1, 2, 4-7
Model 3: Patient Self-Testing and Patient Self-Management
- Model 3a: Patient Self-Testing
Many patients can, after proper training, test their own INR at home or on the go. The patient simply assumes the task of measuring INR, while the dosing decision is up to the treating physician. This model, in which a patient uses a point of care device at home but the physician is making the dosing decision is the most common model for home testing.
- Portable devices can measure INR with just a drop of capillary blood16
- Battery-operated models, including CoaguChek, are accurate16 and approved by the FDA for home use
- PST and PSM are recommended over outpatient INR monitoring for warfarin-treated patients who are motivated and demonstrate competency in self-management strategies17
- Among the advantages of patient self-testing are:
- Reduction in the costs and inconvenience of frequent clinic and laboratory visits16
- Better anticoagulation control18; improved time in therapeutic range17
- Improved health outcomes18 including significant reduction in thromboembolic events19
To see how actual patients feel about self-testing, see the testimonials page.
- Model 3b: Patient Self-Managment
Some patients, after further training can assume responsibility for testing their INR as well as adjusting their VKA dose, (within limits) based on their own test results. In Germany for example, there are over 160,000 patients testing and adjusting their dosage of their anticoagulation drug. Of course, these patients remain in regular contact with their healthcare professional should they have any issue or question.
- Clinical Benefits
Studies show that INR self-monitoring makes oral anticoagulation more effective:
- INR results and VKA dose adjustment are available within minutes.
- Significant improvement of the quality of oral anticoagulation, better therapy adjustment and fewer INR fluctuations. 8
Increased time within the therapeutic range, correlating with a reduction of thromboembolic
Relative risk reduction in patient self-testing and self-management vs. usual care
PST shows a significant reduction of 19% in mortality, bleeding (44%) and thromboembolic complications (43%) vs. usual care. PSM further reduces mortality and thromboembolic events.2
- Reduction in the number and duration of periods spent in hospital 11
- No dependence on country- and manufacturer-specific reagents
- Greater safety when living conditions change 3
Proven long-term cost-benefit for the healthcare system
- Benefits for the Patient
There are many benefits of patient self-management and patient self-testing which significantly improve the quality of life.
- Patients gain more independence, e.g. they do not need to apply for days-off, and travelling is much easier 4,14
- The patient feels more involved in managing his/her condition, leading to better compliance15
- Sampling is almost pain-free and less blood is needed compared to venous sampling: only one small drop from the fingertip is enough.
- Benefits for the Healthcare Professional
- No phlebotomy service required: INR is measured with just a drop of capillary blood, results are discussed and the necessary dosage introduced on the spot within minutes
- All in a single consultation: there is no time lost sending in samples and waiting for the results. Fewer consultations are necessary and administration overheads are reduced
- The patient feels he/she is being competently supervised, is more satisfied by the consultation, leading to improved compliance and a trusting doctor-patient relationship
- INR testing is always done with the same device or the same family of instruments. Results are not affected by using different methods or reagents 10. The result can be directly compared with earlier results, changes show up immediately, and therapy can be adjusted with immediate effect
Point of Care - Testing - Confidence is the key to therapy success
The small and lightweight CoaguChek® XS system is designed especially for patient self-testing or self-monitoring. Because the measurement module is the same as the CoaguChek® XS Plus and Pro systems, if you use CoaguChek in your office, you can rest assured that your patients' measurements will correlate well with tests you perform.
1. Lind SE, Pearce LA, Feinberg WM, Bovill EG. Clinically significant differences in the International Normalized Ratio measured with reagents of different sensitivities. SPAF Investigators. Stroke Prevention in Atrial Fibrillation. Blood Coagul Fibrinolysis 1999; 10:215-227.
2. Heneghan C, Alonso-Coello P, Garcia-Alamino JM, Perera R, Meats E, Glasziou P. Self-monitoring of oral anticoagulation: a systematic review and meta-analysis. Lancet 2006; 367:404-411.
3. Ansell J, Jacobson A, Levy J, Voller H, Hasenkam JM. Guidelines for implementation of patient self-testing and patient self-management of oral anticoagulation. International consensus guidelines prepared by International Self-Monitoring Association for Oral Anticoagulation. Int J Cardiol 2005; 99:37-45.
4. Cromheecke ME, Levi M, Colly LP, et al. Oral anticoagulation self-management and management by a specialist anticoagulation clinic: a randomised cross-over comparison. Lancet 2000; 356:97-102.
5. Voller H, Glatz J, Taborski U, Bernardo A, Dovifat C, Heidinger K. Self-management of oral anticoagulation in nonvalvular atrial fibrillation (SMAAF study). Z Kardiol 2005; 94:182-186.
6. Sawicki PT, Glaser B, Kleespies C, et al. Self-management of oral anticoagulation: long-term results. J Intern Med 2003; 254:515-516.
7. Garcia-Alamino JM, Ward AM, Alonso-Coello P, et al. Self-monitoring and self-management of oral anticoagulation. Cochrane Database Syst Rev; 4:CD003839.
8. Koertke H, Minami K, Boethig D, et al. INR self-management permits lower anticoagulation levels after mechanical heart valve replacement. Circulation 2003; 108 Suppl 1:II75-78.
9. Menendez-Jandula 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.
10. Chiquette E, Amato MG, Bussey HI. Comparison of an anticoagulation clinic with usual medical care: anticoagulation control, patient outcomes, and health care costs. Arch Intern Med 1998; 158:1641-1647.
11. Koertke H, Minami K, Bairaktaris A, Wagner O, Koerfer R. INR self-management following mechanical heart valve replacement. J Thromb Thrombolysis 2000; 9 Suppl 1:S41-45.
12. 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; 153:1441-1447.
13. Taborski U, Wittstamm FJ, Bernardo A. Cost-effectiveness of self-managed anticoagulant therapy in Germany. Semin Thromb Hemost 1999; 25:103-107.
14. Sawicki PT. A structured teaching and self-management program for patients receiving oral anticoagulation: a randomized controlled trial. Working Group for the Study of Patient Self-Management of Oral Anticoagulation. Jama 1999; 281:145-150.
15. Diehm C. [Self-management of anticoagulation therapy]. MMW Fortschr Med 2005; 147:34-36.
16. Bloomfield HE et al (2011) Ann Int Med 154:472-482
17. Guyatt et al (2012). Chest 141:7S-47S
18. Levi et al (2009). Sem Thromb Hem 35:527-542
19. Heneghan et al (2012). Lancet 379:292-293
20. Phillips KW, Ansell J. Outpatient management of oral vitamin K antagonist therapy: defining and measuring high-quality management. Expert Rev Cardiovasc Ther 2008; 6:57-70
21. 33. Woods, K., Douketis, J.D., Schnurr, T., Kinnon, K., Powers, P. et al. (2004). Patient preferences for capillary vs. venous INR determination in an anticoagulation clinic: a randomized controlled trial. Thromb Res 114(3), 161-165.