Improving patients time in range on warfarin

Warfarin is one of the most widely used anticoagulants in the United Kingdom. Patients taking warfarin need regular International Normalised Ratio (INR) blood tests to ensure that their levels remain within a set therapeutic range.

Should patients fall below this range they will be at higher risk of developing a venous thromboembolism (VTE). If patients INR were to go above range they are at greater risk of bleeding. In order to achieve best patient safety it is vital that patients are kept within their set therapeutic range. The purpose of this service improvement was to address the issue of patients on Warfarin with a poor time in range (TIR) and to determine what could be done to improve these patients overall TIR.

The benefit of anticoagulation in the elderly is positive, however the highest benefit in elderly patients treated with warfarin were those who achieved a TIR of 65% or higher. (NICE Guidelines, 2014) Jones, et al (2005) noted that even in patients who appear to have good control, instability of INR results has substantial implications for mortality and other clinical outcomes. An association was found between INR results outside the therapeutic range and an increased rate of hospitalisation, mortality and an increased likelihood of thromboembolic events.

There is a need for regular monitoring, which brings with it associated costs and burdens, and there are numerous other factors that can impact upon INR results. Molteni and Cimminiello (2014) discuss these issues and state the difficulties in keeping patients within 60% time in range, noting that anticoagulation nurse specialist services have proved very effective in this regard. This too is an important consideration as it has been noted that high warfarin dose fluctuation can lead to an increased risk of bleeding and thromboembolism. Previously assessments for patients were done in an ad hoc manner but now a more standardised approach was planned to improve efficiency and productivity.

We involved patients in their care by ensuring communication and involving them in their care decisions. We have a large number of patients on warfarin around 4000 in our trust alone so the findings of this can be far reaching and this project has recently been recognised by the nursing times (see attached document).

NICE guidelines (recommendation 1.6.10) states that the standard for monitoring patients TIR is below 65%. For this research patients 40% and below were chosen. This was due to time and staff restraints at the time of initiation. Patients were contacted to determine possible reasons for the poor control and measures could be implemented that could potentially improve the TIR. This could involve patient education, changes to patient’s diet and lifestyle, change to methods taken for example, use of a dosette box, or exploring the possibility of switching the anticoagulant given, if appropriate, from Warfarin to a DOAC.

We felt that it was important to include patients in their care and understand their issues with the medication. Through discussion with the patients we were able to understand the barriers to them in managing their care. We aimed to improve self-management of their anticoagulation so actively involved patients in discussions to determine what would be the best intervention for the individual.

If poor compliance was deemed as an issue, patients compliance was assessed in greater detail before considering switching patients to a DOAC. Generally we did not switch patients if their compliance was poor as we would be less able to monitor their blood levels. For those with poor TIR, despite regularly taking the medication, phone alarm reminders and dosette box were encouraged with the patients agreement.

Senior Anticoagulation Nurses Specialists responsible for the development of the TIR project met to identify objectives regarding the implementation of work required to achieve the desired end result, which would be to improve a patient’s poor time in range or to implement the change of the anticoagulant from Warfarin to a DOAC. This was presented to the consultant and any suggested adjustments made. The team requested that a report be written by DAWN Anticoagulation Clinical Software which would enable the identification of those patients with a poor time in range, using the NICE guidelines for Anticoagulation control as a framework. DAWN AC software also developed a new file in the patients’ anticoagulation records so that follow up and review dates could be entered.

A DOAC exclusion criteria was written, to be used in conjunction with this pathway, so ensuring those patients unsuitable for a DOAC would not be switched from Warfarin. A pro-forma for the switching of patients from Warfarin to a DOAC was created in order to document the findings from the investigations carried out when a patient was identified as having a poor TIR.When these developments were in place staff were then able to contact patients and discuss their poor time and range in a clear and standardised manner. This would include increasing patient education, learning more about patients’ lifestyle choices and informing patients of suitability for DOACs.

As a result of the 12-month service improvement, 166 patients were identified as having poor TIR below 40% and two clear improvements were identified. Firstly, 35% of patients were switched to a DOAC. This will mean less hospital visits, monitoring will be required. DOACs also have fewer interactions with alcohol and other medications. The effectiveness of warfarin is dependent on the quality of control within the INRs therapeutic range. If this is not achieved patients may be better suited to switching therapy to a DOAC (Kim, et al, 2019) Secondly, 89% of the patients, who remained on warfarin and had a recording of TIR 12 months post intervention, showed an improvement in their TIR.

Clear benefits were found from increasing nursing interventions in this patient group and further resources and time are needed to further develop this improvement. NICE guidelines (2014) state that anticoagulation should be reviewed for patients with 2 INR values higher than 5 or 1 INR value higher than 8 within the past 6 months and patients with 2 INR values less than 1.5 within the past 6 months. It would be beneficial to extend further study to include these patients to improve patient safety. Only patients with TIR of less than 40% were contacted in this study due to staffing limitations and resources. NICE guidelines state that a TIR of below 65% should trigger re-assessment of anticoagulation control. Further support is needed in order to increase the scope of this service improvement to include all patients with a TIR of less than 65%. In doing so it can be seen that long-term improvements can be made to patient experience and patient safety, while also saving the trust money in unneeded blood tests and patient visits

The key learning is that through involving patients in their care and having clear guidelines planned you can improve patients time in range in simple ways that can have a big impact upon patients and the trust. in future we are expanding the TIR team so we can target patients with higher time in range e.g. 50% so that our standards are raised even higher. If other organisations have any questions we would be more than happy to assist.

We did not measure, at the time, the number of patients where TIR is 41-65% however could measure this number now. We plan to tackle this number by adding the numbers of staff working on this service improvement study and have now subsequently raised the threshold of patient to include those up to 55% and the next phase will be to include those up to 65%.

We found one of the main challenges were time and staffing restraints so it is useful to set aside "project time" and a set team even if this is only one or two nurses at set times to focus on this group of at risk patients.