Challenges with anticoagulation control
For patients on VKAs, effective anticoagulation requires a patient to spend maximum time within their target INR range.1 As shown below, the risks of ischaemic stroke or intracranial bleeding are higher outside of a narrow INR range.2
The risks of ischaemic stroke or intracranial bleeding are higher outside of a narrow INR range2
Adapted from Fuster et al. 2011.2
Maintaining the target INR with VKAs can be challenging owing to their unpredictable response, numerous food and drug interactions and other factors including patient adherence.1,3 Patients receiving warfarin may be poorly controlled (i.e. outside of the 2–3 INR range) around a third of the time, placing them at an increased risk of stroke and bleeding.2,4–6 A UK population-based study revealed that over half (56%) of AF patients on VKAs had <70% TTR.7
In addition to the risks associated with the narrow therapeutic window, VKAs may place a significant burden on both patients and healthcare providers with the need for routine monitoring. A patient receiving warfarin (a VKA) will typically attend 13 INR monitoring appointments each year8 and INR monitoring is the greatest cost associated with VKAs. 8,9
Assessment of anticoagulation control
NICE recommends patients receiving an anticoagulant should have their need for anticoagulation and the quality of anticoagulation reviewed at least annually.10 For patients receiving VKAs, TTR should be calculated at each visit. Patients with poor anticoagulation control shown by any of the following should have their anticoagulation reassessed:10
Adapted from NICE CG180.10
When reassessing anticoagulation, the following factors that may contribute to poor anticoagulation control should be considered and, if possible, addressed:
Adherence to prescribed therapy
Interacting drug therapy
Lifestyle factors including diet and alchol consumption
If poor anticoagulation control cannot be improved, the risks and benefits of alternative stroke prevention strategies should be evaluated and discussed with the patient.10
Further information on assessing anticoagulation control with VKAs is available in NICE CG180.10
Click here to view ELIQUIS (apixaban) prescribing and adverse event reporting information.
AF = Atrial Fibrillation INR = International Normalised Ratio NICE = National Institute for Health and Care Excellence
NOAC = Non-VKA Oral Anticoagulant TTR = Time in Therapeutic Range VKA = Vitamin K Antagonist
- Lip GY et al. Nat Rev Dis Primers 2016; 16016. doi: 10.1038/nrdp.2016.16.
- Fuster V et al. Circulation 2011;123:e269–e367.
- Lin YP et al. Medicine (Baltimore) 2015; 94: e1627.
- Wallentin L et al. Circulation 2013;127:2166–2176.
- Gallagher A et al. Thromb Haemost 2011;106:968–977.
- White H et al. Arch Intern Med 2007;167:239–245.
- Macedo AF et al. Thrombosis Res 2015;136:250–60.
- Anticoagulation UK. Out of range: audit of anticoagulation management in secondary care in England. April 2018. Available at: http://www.anticoagulationuk.org/news/2018-05-14-anticoagulation-uk-is-pleased-to-publish-a-new-report-out-of-range-audit-of-anticoagulation-management-in-secondary-care-in-england. Accessed August 2019.
- NHS England. Factsheet: Increase prescription of anti-thrombotics (warfarin) by supporting GPs to identify patients with atrial fibrillation. Available at: https://www.england.nhs.uk/wp-content/uploads/2014/02/pm-fs-3-3.pdf. Accessed August 2019.
- NICE CG180. 2014. Available at: https://www.nice.org.uk/guidance/cg180. Accessed August 2019.
Job code: 432UK1900440-01
Date of preparation: September 2019