A smartphone application for remote adjustment of warfarin dose: Development and usability study

AIM

The aim of this article is (a) to design and develop a smartphone app called Alfalfa that can provide remote dose adjustment (b) to evaluate its usability.

BACKGROUND

Patients taking warfarin need to spend substantial time, money, and energy frequently visiting the hospital in order to adjust its dose. Internet technology may be able to provide convenient dose adjustment services for these patients.

METHODS

We thought and discussed repeatedly about how to ensure the safety and effectiveness of remote administration of warfarin, and finally designed and developed the Alfalfa app. In addition, patients and medical practitioners were invited to participate in a system usability scale (SUS) to assess the usability of Alfalfa.

RESULTS

As of July 5, 2021, the number of Alfalfa accounts was 1736, including 1624 patients and 112 medical staff, and it provided a total of 12,968 remote dose adjustments. A total of 26 people participated in the questionnaire, including 15 patients and 11 medical staff. The results of SUS show that the usability score of patient terminal and medical terminal is 61.8 and 82.7, respectively. And age does not affect the usability of patient terminal. The usability of the Alfalfa app was rated similarly by younger and older adults (63.5 vs. 58.5, P = .535).

CONCLUSIONS

This study proves that the Alfalfa app can be used for remote management of warfarin. The usability of medical terminal is acceptable to medical practitioners, while the usability of patient terminal needs further improvement.

TRIAL REGISTRATION

ChiCTR1900021920.

Anticoagulation Control in Different Ethnic Groups Receiving Vitamin K Antagonist for Stroke Prevention in Atrial Fibrillation

Vitamin K antagonist such as warfarin reduces the risk of stroke in atrial fibrillation (AF) patients. Since warfarin has a narrow therapeutic index, its administration needs to be regularly monitored to avoid any adverse clinical outcomes such as stroke and bleeding. The quality of anticoagulation control with warfarin therapy can be measured by using time in therapeutic range (TTR). This review focuses on the prevalence of AF, quality of anticoagulation control (TTR) and adverse clinical outcome in AF patients within different ethnic groups receiving warfarin therapy for stroke prevention. A literature search was conducted in Embase and PubMed using keywords of “prevalence,” “atrial fibrillation,” “stroke prevention,” “oral anticoagulants,” “warfarin,” “ethnicities,” “race” “time in therapeutic range,” “adverse clinical outcome,” “stroke, bleeding.” Articles published by 1st February 2020 were included. Forty-one studies were included in the final review consisting of AF prevalence (n = 14 studies), time in therapeutic range (n = 18 studies), adverse clinical outcome (n = 9 studies) within different ethnic groups. Findings indicate that higher prevalence of AF but better anticoagulation control among the Whites as compared to other ethnicities. Of note, non-whites had higher risk of strokes and bleeding outcomes while on warfarin therapy. Addressing disparities in prevention and healthcare resource allocation could potentially improve AF-related outcomes in minorities.

Influence of age on the relationship between apixaban concentration and anti-factor Xa activity in older patients with non-valvular atrial fibrillation

BACKGROUND/OBJECTIVES

Despite lower major bleeding rates associated with direct oral anticoagulants (DOACs) as compared to conventional warfarin therapy, bleeding rates remain higher in older patients compared to younger patients suggesting a potential role for DOAC measurements. The objective of this study is to examine the effect of age on the relationship between apixaban concentrations and anti-Factor Xa activity in patients with non-valvular atrial fibrillation (NVAF).

METHODS

This is a retrospective analysis based on a database created using data from the ARISTOTLE study. Outpatient, stable adult patients with NVAF receiving apixaban were included in this study. Data collection consisted of apixaban concentration, anti-Factor Xa activity, age, weight, creatinine, and co-medications.

RESULTS

The database composed of 2058 patients receiving apixaban. Distribution of race, NVAF subtype, and aspirin use was fairly similar across each age quantile. Older patients received a higher number of co-medications and received the 2.5 mg apixaban dose more often as compared to younger patients (22% vs. < 1%). Linear regression demonstrated that the unadjusted slope for apixaban concentration effect on anti-Factor Xa activity was similar across each age quantile. Although, the overall adjusted linear regression analysis demonstrated that the age by concentration interaction was statistically significant, relative differences in anti-Factor Xa activity (< 8%) were not clinically meaningful.

CONCLUSION

Data on apixaban concentrations and anti-Factor Xa activity from a pivotal randomized double-blind study of apixaban for the prevention of stroke in NVAF patients have confirmed that the chromogenic anti-Factor Xa activity assay can accurately assess apixaban concentrations in patients regardless of age. Age was not associated with a clinically relevant change in the apixaban vs. anti-Factor Xa activity response relationship and target ranges are unchanged.

Long-Term Statin Administration Does Not Affect Warfarin Time in Therapeutic Range in Australia or Singapore

BACKGROUND

Warfarin requires ongoing monitoring of the International Normalised Ratio (INR). This is because numerous factors influence the response, including drug interactions with commonly-prescribed medications, such as statins. The administration of statins with warfarin may change INR; however, there is limited information regarding the effects on warfarin control as measured by time in therapeutic range (TTR). Statins may also alter bleeds with warfarin, but there are conflicting reports demonstrating both increased and decreased bleeds, and limited data on diverse ethnic populations. Therefore, the aim of this study was to determine the effect of statin administration on warfarin control and bleeds in patients in Australia and Singapore.

METHODS

Retrospective data were collected for patients on warfarin between January and June 2014 in Australia and Singapore. Patient data were used to calculate TTR and bleed events. Concurrent statin therapy was assessed and comparisons of TTR and bleed incidence were made across patient subgroups.

RESULTS

Warfarin control in Australia and Singapore was not significantly affected by statins, as measured by TTR (83% and 58%, respectively), frequency of testing, and warfarin doses. In Australia, statin use did not significantly affect bleeds, whilst in Singapore the bleed incidence was significantly lower for patients on statins.

CONCLUSIONS

Chronic concurrent administration of statins with warfarin does not adversely affect warfarin TTR in Australia or Singapore. In Singapore, patients on statins, compared to no statins, had a lower bleed incidence and this requires further investigation, especially given the potential genetic influences of ethnicity on both statin and warfarin metabolism.

Unnecessary overuse. Study of "inadvisable practices" for patients with atrial fibrillation

OBJECTIVE

To identify overuse (diagnostic, therapeutic and self-care practices that represent risks that outweigh the potential benefits) in patients with atrial fibrillation.

METHOD

The study was based on qualitative research techniques. Using the "Metaplan" technique, we identified and ordered potentially inappropriate, ineffective and inefficient practices. By means of a consensus conference, we then established a number of "inadvisable practice" measures (relatively common practices that should be eliminated based on the scientific evidence or clinical experience). Professionals from the specialties of cardiology, haematology, neurology, internal medicine, family medicine and nursing participated in the consensus.

RESULTS

We developed a catalogue of 19 "inadvisable practices" related to the diagnosis, treatment and care of anticoagulated patients that were inappropriate, had questionable effectiveness or were ineffective, as well as 13 beliefs or behaviours for anticoagulated patients that could result in injury or were useless or inefficient.

CONCLUSION

The "inadvisable practices" approach helps identify practices that represent greater risks than benefits for patients. It seems appropriate to include algorithms in the clinical decision-making support systems that consider this information for the diagnosis, treatment and for home care. For this last case, recommendations have also been prepared that define specific contents for the healthcare education of these patients.

Pharmacologic Therapies in Anticoagulation

Anticoagulants are beneficial for prevention and treatment of venous thromboembolism and stroke prevention in atrial fibrillation. The development of target-specific oral anticoagulants is changing the landscape of anticoagulation therapy and created growing interest on this subject. Understanding the pharmacology of different anticoagulants is the first step to adequately treat patients with best available therapy while avoiding serious bleeding complications. This article reviews the pharmacology of the main anticoagulant classes (vitamin K antagonists, direct oral anticoagulants, and heparins) and their clinical indications based on evidence-based data currently available in the literature.