The Importance of Time within Therapeutic Range (TTR)
TTR is the optimal measure of INR control, and has a significant relationship with adverse outcomes in all studies1
As a result:
- a 7% increase in TTR →1 less major haemorrhage/100 patient years
- a 12% increase in TTR →1 less thromboembolic event/100 patient years
- a 5% improvement in time in therapeutic range across UK anticoagulation clinics would prevent 400-500 strokes per year2
In international studies, a marked benefit was found against stroke and total vascular events for patients who had mean TTRs ≥65%2
What can lead to low TTR?
- Lack of a clinical governance process to monitor and regulate the implementation of existing guidelines - medical practice is an important determinant of TTR3
- Lack of effective, ongoing dose adjustment1
- Patient non-compliance: compliance rates have been estimated at 50%- 60% for patients on long term medication4. Non compliance has been associated with poor treatment outcomes.
Achieving 65% TTR and greater
Near patient testing
- Over 350 primary care sites have implemented Near Patient Testing with CoaguChek® professional use systems.
- Use of Computer Decision Support Software (CDSS) allows for practice and patient audit of TTR
- Availability of an external quality assurance scheme for CoaguChek® professional use systems from UK NEQAS
Patient self testing
- Over 10,000 patients in the UK are self-monitoring, either:5
- self-testing – carrying out their own blood tests with dose adjustments made by HCPs
- self-managing – carrying out their own blood tests and adjusting their dose according to local agreement protocol
- Published data shows that self-management could deliver TTR of up to 85%6
CoaguChek® patient use systems – tried and trusted
- Fully evaluated by the NHS – Centre for Evidence based Purchasing (CEP) 2006
- Recommended as option for specific patients in NICE AF guidelines 20067
- Accurate (ISI of 1.0) and precise (CV<4.5%)8 – giving reproducible results time after time
1. Wan Y et al. Anticoagulation Control and Prediction of Adverse Events in Patients With Atrial Fibrillation. A Systematic Review. Circ Cardiovasc Qual Outcomes 2008; DOI: 10.1161/CIRCOUTCOMES.108.796185.
2. Connolly SJ et al. Depends on the Quality of International Normalized Ratio Control Achieved by Benefit of Oral Anticoagulant Over Antiplatelet Therapy in Atrial Fibrillation Centers and Countries as Measured by Time in Therapeutic Range. Circulation 2008; 118:2029-2037.
3. Anticoagulation for Atrial Fibrillation A simple overview to support the commissioning of quality services. NHS Improvement – Heart, 2011.
4. DiMatteo MR. Patient adherence to pharmacotherapy: the importance of effective communication. Formulary 1995; 30:596–8, 601–2, 605.
5. Data on File, Roche Diagnostics.
6. Heneghan C et al.. Self monitoring of oral anticoagulation: a systematic review and meta-analysis. Lancet 2006;367:404-411.
7. Atrial fibrillation. The management of atrial fibrillation. NICE clinical guideline 36, June 2006.
8. CoaguChek XS test strip pack insert, Roche Diagnostics 2010.