Improving safety of warfarin prescribing and administration using clinical decision support

There are several benefits of electronic prescribing and medication administration (EPMA) systems, including the ability to support the reduction in medication omission errors​[1,2]​. Researchers suggest that medication administration errors account for just over 50% of reportable medication errors​[3]​

EPMA has proven its capacity to reduce medication error rates; however, it also has the potential to increase errors if not implemented properly​[4]​. Thus, appropriate utilisation of clinical decision support (CDS) — which aids clinicians and other healthcare providers in the decision-making process and continuous development of system applications — is essential to ensure ongoing improvement in patient safety​[5]​.

Appropriate utilisation of EPMA and CDS could improve patients’ safety and quality of service regarding high-alert medication, such as warfarin. A systematic review concluded that appropriate use of electronic systems in warfarin prescribing reduced the time to reach therapeutic range, increased the duration in which the patients were in therapeutic range (TTR) and reduced the risk of haemorrhage​[6]​.

At Barts Health NHS Trust, following EPMA implementation, several incidences involving warfarin were reported, these included dose omissions, administration omissions and delays to prescribing. A multidisciplinary workshop comprising medical, nursing, pharmacy and EPMA team representation, of approximately ten staff members, were tasked to analyse the previous process and suggest solutions to improve patient safety. The team reviewed the previous warfarin care plan and identified four issues and solutions (see Box). 

Box: Issues and solutions for existing warfarin care plan

Issue 1: Prescribing of warfarin had the potential to be missed as there were no reminders to check if warfarin was prescribed.

Solution: A new placeholder fires a task to remind nurses, doctors and pharmacists to check that warfarin is prescribed and to complete the new power form. The placeholder is new bespoke functionality made in the Barts Health ePMA system; its function is to have all relevant warfarin information added into the system that is easily viewable on the drug chart as well as alerting healthcare staff that warfarin needs to be reviewed on a daily basis. A powerform will need to be completed to determine if warfarin has been reviewed for that day. All these data are auditable from the ePMA system. 

Issue 2: Warfarin placeholder was mistaken as a prescription and didn’t serve a functional purpose. 

Solution: A new placeholder was built to include additional warfarin information, such as target  international normalised ratio (INR), indication, duration of treatment and pre-admission doses. 

Issue 3: Failure to prescribe warfarin in usual work hours, not prescribing warfarin on the weekends, running out of orders in the existing care plan, and not documenting intentionally missed doses on the prescribing system. 

Solution: Instead of one order for warfarin (leading to several care plans) there will now be seven orders of warfarin and seven omit dose orders for each day of the week. The care plan is now valid for one week.

Issue 4: Blood tests and essential pathology tests were missed, particularly when loading in the out-of-hours service and at the weekends.

Solution: Additional orders were added to the initiation and post-initiation care plan that included INR and full blood count, in line with trust guidance. 

A retrospective pre- and post-service evaluation was undertaken on the cardiothoracic wards at St Bartholomew’s Hospital in London to investigate the incidence of warfarin missed doses before and after the care plan updates. Data were analysed for all patients taking warfarin who were on selected wards between June 2022 and December 2022. 

The data showed that 936 (90.9%) out of 1,060 total warfarin doses were administered before updating the care plan, while 97 doses were omitted either intentionally (2.8%; n=29), through unintentionally missed prescription (5.9%; n=62) or unintentionally missed administration (0.6%; n=6). The total of warfarin missed doses rate was 9.2%.  

After a successful amendment on the EPMA warfarin care plan, 830 (93.5%) warfarin doses were administered out of 888 total warfarin doses; 58 doses were omitted either intentionally (4.2%; n=37), through unintentionally missed prescription (1.8%; n=16) or unintentionally missed administration (0.6%; n=5). The total warfarin missed doses rate following the care plan amendment was 6.5%.

In a systematic review focusing on using CDS to improve prescribing of oral anticoagulants, published in 2020, almost half of the studies included showed a positive impact of CDS in the process of care outcomes for patients with anticoagulation treatment​[5]​. It also revealed that studies that implemented EPMA and integrated it with CDS reported reduced prescribing errors​[5]​.

Another review, also published in 2020, showed improvement in the quality measures of venous thromboembolism (VTE) and in the anticoagulation safety measures post-combined integration of EPMA along with CDS, even though there were not significant improvements in clinical outcomes such as length of stay (LOS)​[7]​.

Our results demonstrate a positive impact of CDS in conjunction with EPMA to further enhance patient safety, in particular around warfarin dosing. Our analysis pre- and post-updating the care plan has demonstrated an absolute reduction in unintentional missed prescription by 4.1%. There were also general improvements in the number of administered doses and the number of intentional omissions of warfarin doses. 

Moving forward, this analysis has highlighted for the trust that reviews of workflows embedded in the ePMA system for all high-risk medications need to be reviewed to ensure that they are improving patient safety and functioning as expected.

Best-practice principles were also recommended, which can be applied when making any change in ePMA: 

  • Large trusts with multiple sites should ensure that there is network engagement across all sites regarding the workflow and new designs;
  • Engage a high proportion of the end users, in this case junior doctors and ward staff who will be prescribing and administering warfarin on a regular basis;
  • Link in with supportive teams within informatics like the testing team (to fully test new functionality) and change team (to review learning material);
  • Have an implementation plan, launch date and education and training plan (including updating e-learning and user guides) to implement change;
  • Utilise data from reports, audits and electronic incident reporting systems (e.g. DATIX) to drive change in the electronic system to improve patient safety. 

Sarah Halawani, international MSc student (trainee pharmacist); Reena Lal, deputy lead ePMA pharmacist; and Paul Wright, lead cardiovascular pharmacist, all at Barts Health NHS Trust

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    Sennesael A-L, Krug B, Sneyers B, et al. Do computerized clinical decision support systems improve the prescribing of oral anticoagulants? A systematic review. Thrombosis Research. 2020;187:79–87. doi:10.1016/j.thromres.2019.12.023
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    CHATELLIER G, COLOMBET I, DEGOULET P. An overview of the effect of computer-assisted management of anticoagulant therapy on the quality of anticoagulation. International Journal of Medical Informatics. 1998;49:311–20. doi:10.1016/s1386-5056(98)00087-2
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Last updated
The Pharmaceutical Journal, PJ, September 2023, Vol 311, No 7977;311(7977)::DOI:10.1211/PJ.2023.1.196460

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