Optimising warfarin management: an exploration of pharmacist-delivered models of care

Warfarin has been the mainstay of preventing and treating thromboembolism for over 50 years and is currently taken by over 200,000 Australians. Optimal management of warfarin relies on regular monitoring of the International Normalised Ratio (INR), appropriate dose adjustment, effective communication and comprehensive patient education. Therapy may be managed by a range of healthcare providers in a variety of settings, and by patients themselves, although management in Australia has tended to focus on traditional office and pathology based models. Internationally, however, alternative models of care are playing an increasingly significant role with positive results and pharmacists have been shown to be effective in improving the quality use of warfarin through a variety of these service delivery models. The main objective of this thesis was to examine the effect of using pharmacist delivered models of care on warfarin management within Australia through a number of complementary projects. Guidelines recommend aiming for a target INR control of upwards of 70% time in range. Internationally, community-based studies consistently demonstrate suboptimal levels of INR control, although little data is available on the level of control achieved through usual models of care in Australia. A retrospective cross sectional study of INR results from 442 Australian veterans was undertaken to determine the INR control of a usual care population. The mean time in INR range was 61.8% in this population. This suggests a potential role for strategies aiming to improve INR control among Australian patients in line with best practice guidelines. Review of the literature suggested pharmacists could play a role in improving warfarin management through optimising the delivery of education, improving access to INR testing and facilitating patient self-monitoring. A series of sub-projects were designed to develop and pilot tools to support pharmacists in addressing these strategies. A website was designed to provide patients and health professionals with educational resources regarding anticoagulation. The site aimed to be a comprehensive and reliable online resource and was promoted directly to pharmacists. It received high levels of utilisation, with almost 250,000 views in 12 months, and positive feedback from health professionals and patients, and proved to be an important educational resource that was an easy and accessible tool for pharmacists to use to complement face to face counselling services and further improve patients’ knowledge about warfarin therapy. Tools and resources were developed to improve access to INR testing by facilitating the introduction of anticoagulation services, including pharmacist-delivered INR clinics, in Australia. A pilot was conducted in three rural community pharmacies, with a subsequent project involving 36 pharmacies. While the resources received positive feedback from participating pharmacists, the rate of successful service implementation was low. Despite the perceived benefits to the communities, the current model of healthcare remuneration in Australia impacted on the long term financial viability of such services. Development, implementation and evaluation of a pharmacy-centred pathway to enable patient self-monitoring (PSM) was also undertaken. Forty-eight patients successfully underwent training and participated in PSM for a median of 16.9 months. INR control data during PSM was compared to that from the six months prior to entering the study for 46 of the 48 patients. There was a significant improvement in INR control, with the mean time in range increasing from 64.0% to 72.9% (p