References

Jennings I, Kitchen D, Keeling D, Fitzmaurice D, Heneghan C Patient self-testing and self-management of oral anticoagulation with vitamin K antagonists: guidance from the British Committee for Standards in Haematology. Br J Haematol. 2014; 167:(5)600-607 https://doi.org/10.1111/bjh.13070

London Stroke Clinical Network. Pan London framework for adult patients who self-monitor their INR. 2016. https://tinyurl.com/2p9eev72 (accessed 25 January 2022)

Medicines and Healthcare Products Regulatory Agency. Warfarin and other anticoagulants—monitoring of patients during the COVID-19 pandemic. 2020. https://tinyurl.com/ye255h2u (accessed 25 January 2022)

National Institute for Health and Care Excellence. Atrial fibrillation and heart valve disease: self-monitoring coagulation status using point-of-care coagulometers (the CoaguCheck XS system). Diagnostics guidance DG14. 2017. https://www.nice.org.uk/guidance/dg14 (accessed 25 January 2022)

National Institute for Health and Care Excellence. Atrial fibrillation. Quality standard QS93. 2018. https://www.nice.org.uk/guidance/qs93/chapter/quality-statement-6-developmental-selfmonitoring-of-anticoagulation (accessed 25 January 2022)

NHS England and NHS Improvement. Clinical guide for the management of anticoagulant services during the coronavirus pandemic. 2021. https://www.nice.org.uk/Media/Default/About/COVID-19/Specialty-guides/specialty-guide-anticoagulant-services-and-coronavirus.pdf (accessed 25 January 2022)

Patel R, Czuprynska J, Roberts LN Switching warfarin patients to a direct oral anticoagulant during the coronavirus disease-19 pandemic. Thromb Res. 2021; 197:192-194 https://doi.org/10.1016/j.thromres.2020.11.004

Reiffel JA. Time in the therapeutic range for patients taking warfarin in clinical trials: useful, but also misleading, misused, and overinterpreted. Circulation. 2017; 135:(16)1475-1477 https://doi.org/10.1161/CIRCULATIONAHA.116.026854

Rosendaal FR, Cannegieter SC, van der Meer FJM, Briët E. A method to determine the optimal intensity of oral anticoagulant therapy. Thromb Haemost. 1993; 69:(03)236-239 https://doi.org/10.1055/s-0038-1651587

Sharma P, Scotland G, Cruickshank M Clinical and cost-effectiveness of point-of-care tests (CoaguChek system, INRatio2 PT/INR monitor and ProTime Microcoagulation system) for the self-monitoring of the coagulation status of people receiving long-term vitamin K antagonist therapy compared with standard UK practice: systematic review and economic evaluation. Health Technol Assess. 2015; 19:(48)1-172 https://doi.org/10.3310/hta19480

Speed V, Patel RK, Byrne R, Roberts LN, Arya R. A perfect storm: root cause analysis of supra-therapeutic anticoagulation with vitamin K antagonists during the COVID-19 pandemic. Thromb Res. 2020; 192:73-74 https://doi.org/10.1016/j.thromres.2020.05.024

Keeping warfarin patients safe during the COVID-19 pandemic: review of an INR self-testing programme

10 February 2022
10 min read
Volume 31 · Issue 3

Abstract

Background:

Anticoagulation clinics faced an unprecedented challenge during the COVID-19 pandemic to safely manage patients on warfarin therapy.

Methods:

A London teaching hospital trust received INR point-of-care (POC) testing devices from its clinical commissioning group. The Trust distributed the devices to patients who were cognitively and physically able to self-test and evaluated clinical outcomes and patient experience.

Findings:

A significant improvement in warfarin control (mean time in therapeutic range (TTR) before POC 52%, standard deviation (SD) 24.8, vs mean after 60.7%, SD 19.7; P>0.009) and a 39% reduction in missed appointments were seen in self-testing patients. Positive patient satisfaction and lifestyle outcomes were identified through a telephone survey. A minority of patients struggled with the technique, leading to frustration. Some patients used many test strips through unsuccessful and additional tests.

Conclusion:

POC testing in a carefully selected group of patients on warfarin therapy resulted in positive clinical and patient satisfaction outcomes. Appropriate governance processes are needed, and clinical expertise is required to support patients. Cost-effectiveness of POC testing needs careful monitoring.

The use of warfarin therapy has declined over the last decade with the introduction of direct oral anticoagulants (DOACs). However, it remains the mainstay of treatment for several groups of patients including those with mechanical heart valves, valvular atrial fibrillation and antiphospholipid syndrome.

Safe and effective warfarin management requires regular international normalised ratio (INR) monitoring. The INR is a standardised test of blood coagulation that can be performed by venous blood test, usually processed by a hospital laboratory, or capillary blood test, performed using a point-of-care (POC) testing device, similar to devices used for monitoring blood sugar levels in diabetic patients. All patients taking warfarin have a therapeutic INR target range indicating the safest level of anticoagulation for them; typically, this is an INR value between 2 and 3. The aim of warfarin management is to balance over-anticoagulation and its associated risk of bleeding with under-anticoagulation and its associated risk of thrombotic events.

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