Extended International Normalized Ratio testing intervals for warfarin-treated patients

Concomitant administration of warfarin and toremifene: A case report

WHAT IS KNOWN AND OBJECTIVE

Antiestrogen agents have been reported to enhance the anticoagulant activity of warfarin. The use of tamoxifen with warfarin has been contraindicated. However, warfarin in combination with toremifene has not been reported. We report a case in which warfarin was combined with toremifene and applied warfarin dose prediction models to predict the dose of warfarin.

CASE SUMMARY

We report the case of a 50-year-old woman with a history of breast cancer, who underwent long-term toremifene therapy after mastectomy. The patient was treated with warfarin after prosthetic valve replacement and had a fluctuating international normalized ratio (INR) following the concomitant administration of toremifene. We applied the warfarin dose prediction model to adjust the warfarin dose during treatment. Finally, her INR stabilized with a lower dose of warfarin, and there was no serious bleeding during the 1-year follow-up.

WHAT IS NEW AND CONCLUSION

Warfarin does not have a serious interaction with toremifene in this case, but it needed about 37.5% dose reduction which was comparable to the interaction of some common antibiotics with warfarin.

Advancing ambulatory pharmacy practice through a crisis: Objectives and strategies used in an ambulatory care action team's response to the COVID-19 pandemic

PURPOSE

The objectives and strategies used by an ambulatory care action team operating within a large health system's pharmacy incident command structure during the initial response to the coronavirus disease 2019 (COVID-19) pandemic are discussed.

SUMMARY

In a time of crisis, a pharmacy ambulatory action team was formed to provide ambulatory clinical pharmacy expertise and meet an immediate and ongoing need to limit nonemergent care during the COVID-19 pandemic. By building a strong communication infrastructure and partnership with ambulatory care providers, clinic medical and operational leaderships, clinical laboratory staff, and infusion centers, the team was able to swiftly execute solutions and respond to new issues and requests. Ambulatory care pharmacy practice continued to advance through provision of services to vulnerable patient populations with chronic conditions that were anticipated to experience gaps in care management during the COVID-19 pandemic. These efforts resulted in expansion of pharmacists' involvement in collaborative drug therapy management, support of patients' transition from in-clinic injection to home self-administration, provision of medication assistance support, and management of 1,300 patients via protocol-based warfarin management. Additionally, ambulatory pharmacy services in 15 primary care, anticoagulation, and specialty clinic sites were transitioned to telehealth. The ambulatory action team also implemented several strategies to manage medication therapy associated with COVID-19-related shortages and implemented electronic decision support to guide prescribing of hydroxychloroquine and azithromycin.

CONCLUSION

Building a strong communication infrastructure and a pharmacy ambulatory action team were essential to respond to a crisis and continue ambulatory clinical pharmacy services expansion.

Thrombosis centres and AVKs monitoring in COVID-19 pandemic

Vitamin K-Antagonists (VKAs) are the treatment of choice in patients with indications other than atrial fibrillation and venous thromboembolism. Moreover, some patients still assume VKAs refusing to change their therapy when direct oral anticoagulants (DOACs) are properly indicated. The COVID-19 pandemic has completely changed our lives, nullifying inter-personal relationships to avoid contagion, making difficult the VKAs monitoring. We describe the re-organization of our thrombosis centre (TC) as an example on how to face the emergency due to the COVID-19 pandemic. In the first phase, to avoid overcrowding at the TC, we planned to increase the interval time between INRs checks and to encourage blood sampling at home, especially for elderly patients. Moreover, precise scheduled blood sampling was also organized while telephone and email counselling were guaranteed by two doctors of the TC. In the second phase, to reduce the number of patients who daily attended our TC a switch from VKAs to DOACs was carried out, if no contraindications were identified. In the third phase, to protect patients, healthcare staff and hospital from COVID-19 widespread, telemedicine was strengthened. We tried to extend self-testing at home by means of portable coagulometers to as more patients as possible. To avoid patients staying or coming back to the TC an ad hoc web platform for sending the therapeutic dose adjustment and the next scheduled appointment was developed. The TC re-organization allowed us to monitor anticoagulated patients respecting personal isolation and security measures to avoid possible COVID-19 contagion.

Managing anticoagulation in the COVID-19 era between lockdown and reopening phases

Patients on anticoagulant treatment are constantly increasing, with an estimated prevalence in Italy of 2% of the total population. The recent spreadout of the COVID-19 pandemic requires a re-organization of Anticoagulation Clinics to prevent person-to-person viral diffusion and continue to offer the highest possible quality of assistance to patients. In this paper, based on the Italian Federation of Anticoagulation Clinics statements, we offer some advice aimed at improving patient care during COVID-19 pandemic, with particular regard to the lockdown and reopening periods. We give practical guidance regarding the following points: (1) re-thinking the AC organization, (2) managing patients on anticoagulants when they become infected by the virus, (3) managing anticoagulation surveillance in non-infected patients during the lockdown period, and (4) organizing the activities during the reopening phases.

Managing anticoagulation in the COVID-19 era between lockdown and reopening phases

Patients on anticoagulant treatment are constantly increasing, with an estimated prevalence in Italy of 2% of the total population. The recent spreadout of the COVID-19 pandemic requires a re-organization of Anticoagulation Clinics to prevent person-to-person viral diffusion and continue to offer the highest possible quality of assistance to patients. In this paper, based on the Italian Federation of Anticoagulation Clinics statements, we offer some advice aimed at improving patient care during COVID-19 pandemic, with particular regard to the lockdown and reopening periods. We give practical guidance regarding the following points: (1) re-thinking the AC organization, (2) managing patients on anticoagulants when they become infected by the virus, (3) managing anticoagulation surveillance in non-infected patients during the lockdown period, and (4) organizing the activities during the reopening phases.

Thromboembolism and anticoagulant therapy during the COVID-19 pandemic: interim clinical guidance from the anticoagulation forum

Coronavirus disease 2019 (COVID-19) is a viral infection that can, in severe cases, result in cytokine storm, systemic inflammatory response and coagulopathy that is prognostic of poor outcomes. While some, but not all, laboratory findings appear similar to sepsis-associated disseminated intravascular coagulopathy (DIC), COVID-19- induced coagulopathy (CIC) appears to be more prothrombotic than hemorrhagic. It has been postulated that CIC may be an uncontrolled immunothrombotic response to COVID-19, and there is growing evidence of venous and arterial thromboembolic events in these critically ill patients. Clinicians around the globe are challenged with rapidly identifying reasonable diagnostic, monitoring and anticoagulant strategies to safely and effectively manage these patients. Thoughtful use of proven, evidence-based approaches must be carefully balanced with integration of rapidly emerging evidence and growing experience. The goal of this document is to provide guidance from the Anticoagulation Forum, a North American organization of anticoagulation providers, regarding use of anticoagulant therapies in patients with COVID-19. We discuss in-hospital and post-discharge venous thromboembolism (VTE) prevention, treatment of suspected but unconfirmed VTE, laboratory monitoring of COVID-19, associated anticoagulant therapies, and essential elements for optimized transitions of care specific to patients with COVID-19.

Thromboembolism and anticoagulant therapy during the COVID-19 pandemic: interim clinical guidance from the anticoagulation forum

Coronavirus disease 2019 (COVID-19) is a viral infection that can, in severe cases, result in cytokine storm, systemic inflammatory response and coagulopathy that is prognostic of poor outcomes. While some, but not all, laboratory findings appear similar to sepsis-associated disseminated intravascular coagulopathy (DIC), COVID-19- induced coagulopathy (CIC) appears to be more prothrombotic than hemorrhagic. It has been postulated that CIC may be an uncontrolled immunothrombotic response to COVID-19, and there is growing evidence of venous and arterial thromboembolic events in these critically ill patients. Clinicians around the globe are challenged with rapidly identifying reasonable diagnostic, monitoring and anticoagulant strategies to safely and effectively manage these patients. Thoughtful use of proven, evidence-based approaches must be carefully balanced with integration of rapidly emerging evidence and growing experience. The goal of this document is to provide guidance from the Anticoagulation Forum, a North American organization of anticoagulation providers, regarding use of anticoagulant therapies in patients with COVID-19. We discuss in-hospital and post-discharge venous thromboembolism (VTE) prevention, treatment of suspected but unconfirmed VTE, laboratory monitoring of COVID-19, associated anticoagulant therapies, and essential elements for optimized transitions of care specific to patients with COVID-19.

Impact of an extended International Normalized Ratio follow-up interval on healthcare use among veteran patients on stable warfarin doses

PURPOSE

To analyze the impact of a 12-week extended International Normalized Ratio (INR) follow-up interval on healthcare use.

METHODS

A prospective cohort study of the use of an extended INR follow-up interval of up to 12 weeks was conducted over 2 years in a pharmacist-managed anticoagulation clinic. A detailed protocol was used to extend the INR follow-up interval to 5-6 weeks and then 7-8 weeks and 11-12 weeks. The number of planned and unplanned anticoagulation encounters, procedures requiring warfarin interruption, telephone triage phone calls, emergency department visits, and hospitalizations were collected. A post hoc subanalysis was also completed on participants who were scheduled for 4 consecutive 12-week intervals.

RESULTS

Compared to baseline, at 12 months there was a mean decrease in planned anticoagulation encounters of 2.24 visits (p < 0.001) among 44 participants. From 12 to 24 months compared to baseline, there was a mean decrease in planned anticoagulation encounters of 3.13 visits (p < 0.001) and an increase of 0.54 unplanned anticoagulation encounters (p = 0.04) among 39 participants. The remainder of healthcare use variables were not statistically significantly different from baseline at any time point. Of the 15 participants scheduled for 4 consecutive 12-week intervals, there was a decrease from baseline of approximately 5 visits over the course of a year (p < 0.001).

CONCLUSION

An extended INR follow-up interval appears to decrease anticoagulation healthcare use without an increase in acute healthcare use. While this intervention could be cost-effective, institutions need to consider safety, efficacy, and feasibility prior to implementation.

Patient Satisfaction With Extended International Normalized Ratio Follow-up Intervals in a Veteran Population

Background: For highly stable warfarin patients, limited data exists regarding patient satisfaction on extended international normalized ratio (INR) follow-up intervals and how this population compares with patients on a direct oral anticoagulant (DOAC). Objective: To assess the impact on patient satisfaction of extending INR follow-up intervals. Methods: Veterans on stable warfarin doses had extended INR follow-up intervals up to 12 weeks in a single-arm prospective cohort study for 2 years. This analysis included participants who completed at least 2 Duke Anticoagulation Satisfaction Scales (DASS). The primary outcome was the change in the DASS. A focus group described participant experiences. Participant satisfaction was compared to patients on a DOAC. Results: Of the 51 participants, 48 were included in the warfarin extended INR follow-up group. Compared with baseline, the mean DASS score (42.9 ± 12.08) was worse at 24 months (46.82 ± 15.2, P = 0.0266), with a small effect size (Cohen's d = 0.29). The 8 participants in the focus group were satisfied with the extended INR follow-up interval but would be uncomfortable extending follow-up past 2 to 3 months. The extended INR follow-up interval study had similar DASS scores as the 33 participants included on DOAC therapy (46.8 ± 15.1, P = 0.9970) but may be limited by differing populations using DOACs. Conclusion and Relevance: For patients currently stable on warfarin therapy, extending the INR follow-up interval up to 12 weeks or changing to a DOAC does not appear to improve patient satisfaction.

Feasibility and safety of a 12-week INR follow-up protocol over 2 years in an anticoagulation clinic: a single-arm prospective cohort study

The 2012 American College of Chest Physicians' guidelines recommended a 12-week INR follow-up interval may be appropriate for patients on stable warfarin doses. Limited evidence supports this recommendation. A single-arm, prospective cohort study over 24 months was completed in a Veterans Affairs anticoagulation clinic to determine the long-term feasibility and safety of implementing an extended INR follow-up interval in Veterans on stable doses of warfarin. Participants were required to have a stable warfarin dose for 6 months prior to enrollment. A prespecified protocol was used to titrate, extend, and manage the INR interval up to 12 weeks. Scheduling of extended INR intervals was a primary outcome. Safety outcomes included major and serious bleeding and thromboembolic events. A post-hoc comparison of baseline characteristics between individuals who were scheduled for at least 4 consecutive 12-week INR follow-up intervals and those who were not was completed. Of the 50 participants, 36 (72%) were scheduled for at least one 12-week interval and 15 (30%) were scheduled for 4 consecutive intervals. There were 2 thromboembolic events that occurred in 1 participant. There were 28 major and serious bleeding events in 19 participants; 8 occurred while on the extended INR interval. In the post-hoc analysis, no participants scheduled for 4 consecutive 12-week intervals had heart failure. Based on 2 years of monitoring, a 12-week INR follow-up interval using a detailed protocol with titration of INR interval extension appears feasible for a subset of patients. Patients with heart failure may not be suitable for this intervention.

International normalised ratio monitoring in the community populations of the Auckland and Northland regions of New Zealand: time in therapeutic range and frequency of testing

BACKGROUND

Warfarin remains a commonly used anticoagulant for the treatment and prevention of thrombosis. To balance the risks and benefits of therapy, monitoring of the international normalised ratio (INR) is necessary. Patients derive most benefit from warfarin when they spend ≥65% of time in the therapeutic range (INR 2-3). We performed an analysis of INR monitoring for the Auckland and Northland regions of New Zealand in order to estimate anticoagulation control and appropriateness of testing at the population level.

METHODS

INR test results and patient demographics (age and sex) were extracted from the laboratory information system of Labtests and Northland Pathology Laboratories for the period of 1 January 2016 to 27 July 2016.

RESULTS

We included 126 184 INR results from 10 922 patients. The median age of patients represented was 74 years and 57% were male. The overall mean time in therapeutic range was 63%, with a mean interval between INR tests of 14 days.

CONCLUSION

Our results indicate that anticoagulant control in our communities could be improved, and that inappropriately frequent INR testing should be redressed. Appropriate interventions could lead to net clinical benefits and reduce resource misallocation.