Surveillance reports to identify duplicate anticoagulant prescribing
Authors: McClay H , Bastian L , Cardell A , Wilcock M 
Published: November 2023

Abstract

Introduction
A number of patients admitted to hospital on direct oral anticoagulants (DOACs) are often switched to low molecular weight heparin (LMWH) for a limited period of time as part of their clinical management. Electronic prescribing systems (EPMA) allow DOACs to be suspended temporarily and then re-started when clinically indicated. However the system does not generate an alert when DOACs are re-started, leading to unintentional co-prescribing of LMWH which could lead to severe patient harm.1,2

Aim
To determine whether anticoagulation surveillance reports reduce the number of inappropriate duplicate anticoagulation prescriptions.

Methods
A retrospective review of duplicate anticoagulation errors was carried out between September 2017 and March 2022 across the 3 main Royal Cornwall hospital sites. Data on all anticoagulant administrations and the administration time was collected from EPMA via Crystal Reporting pre and post intervention with each period covering 831 days. Data was analysed using Excel. As part of the intervention, surveillance reports were set up in December 2019 to identify patients who were prescribed both LMWHs and DOACs. Reports were generated twice a day, 7 days a week and reviewed for patients who were prescribed both LMWHs and DOACs. The ward pharmacists were then alerted of co-prescribing to complete the necessary interventions. As this project falls under the definition of a service evaluation, according to UK NHS Research Ethics Committees, formal ethical approval was not required. This project was registered on the hospital’s clinical audit database.

Results
948,036 doses of LMWH and DOACs were administered (September 2017 to March 2022) with 817 duplicate prescribing identified, a 0.09% error rate.
The longest time on duplicate therapy was dramatically reduced pre and post intervention from 322 hrs to 36 hrs with mean number of hours reduced from 14.03 to 8.07.
The number of patients receiving more than two doses of co-prescribed LMWH and DOAC before the error was rectified, also reduced from 56 (pre-intervention) to 30 (post-intervention). Likewise, the average duration of more than 2 doses of co-prescription reduced from 48.3 to 18.7 hours before the error was corrected.

Discussion/Conclusion
Some limitations of the study are that staffing is more limited on weekends which may have prevented pharmacists actioning these alerts over weekends. Data will only include anticoagulants prescribed on EPMA so excludes some infusions such as unfractionated heparin. Timestamps associated with administrations on EPMA are user-entered so may not be exact to the time given.
Although EPMA generates an alert when patients on DOACs are prescribed LMWHs, it does not provide a similar alert when suspended DOACs are re-started. EPMA providers are planning to develop alerts to correct this. In the interim we have shown that surveillance reports capture co-prescribing of DOACs and LMWH at an earlier stage preventing potential serious patient harm. It also allows for pharmacists to educate prescribers on risks of anticoagulation co-prescribing.
This report is now routine practice, including additional monitoring - patients on warfarin, fondaparinux, LMWH prescribed twice daily and INR levels. We will re-evaluate to include new parameters.

References
1. NHS England Patient Safety Alert (2015). Harm from using low molecular weight heparins when contraindicated. psa-lmwhs.pdf (england.nhs.uk) Accessed 22nd February 2023
2. Rahmanzade R, Diaz FC, Zaugg C, Schuetz P, Salili AR. Therapeutic duplication of anticoagulants: a retrospective study of frequency and consequences in a tertiary referral hospital. Thrombosis Journal 2020;18:14