Evaluation of Anticoagulation Control among Patients Taking Warfarin in University of Gondar Hospital, Northwest Ethiopia

Introduction. Warfarin is a widely used oral anticoagulant in clinical practice. It has variable intraindividual and interindividual dose response and a narrow therapeutic index. Therefore, it requires frequent and regular international normalized ratio (INR) determination to maintain the INR within the therapeutic range. The study evaluated parameters of anticoagulation control among patients on warfarin. Methods. A cross-sectional study was conducted at University of Gondar hospital. A consecutive sampling method was used to recruit study subjects. The anticoagulation control was evaluated by determining the proportion of desired INRs and the proportion of time spent in the therapeutic range (TTR). Logistic regression analysis was used to identify associated factors with adequate TTR. A P value <0.05 was used to declare significant association. Result. A total of 338 study subjects were included in the study. The mean age of patients was 48.8 (SD = 16.4) years. Atrial fibrillation was the commonest indication for warfarin therapy. One-third (33%) of study subjects achieved the desired INRs of 2.0–3.0, while about one-tenth (13%) of patients attained good INR control (TTR ≥ 65%). Multivariate logistic regression analysis revealed no significant association of sociodemographic and clinical characteristics with good TTR outcome. Conclusion. The level of anticoagulation control with warfarin among study subjects was very low. The authors recommend to implement a validated warfarin-dose titration protocol and to establish anticoagulation clinics to mitigate the low anticoagulation level.

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.

The Immediate Effect of COVID-19 Vaccination on Anticoagulation Control in Patients Using Vitamin K Antagonists

Background: In January 2021, the Dutch vaccination programme against SARS-CoV-2 was started. Clinical studies have shown that systemic reactions occur in up to 50% of vaccine recipients. Therefore, COVID-19 vaccination could affect anticoagulation control, potentially leading to an increased risk of thrombotic events and bleeding complications. Aims: To investigate whether the BNT162b2 vaccine affects anticoagulation control in outpatients using Vitamin K antagonists (VKAs). Methods: A case-crossover study was performed in a cohort of outpatient VKA users from four Dutch anticoagulation clinics who received a BNT162b2 vaccine. INR results and VKA dosages before the first vaccination, the reference period, were compared with those after the first and second vaccination. Results: A total of 3148 outpatient VKA users were included, with a mean age (standard deviation (SD)) of 86.7 (8.7) years, of whom 43.8% were male, 67.0% used acenocoumarol and 33.0% phenprocoumon. We observed a decrease of 8.9% of INRs within range in the standard intensity group (target INR 2.0-3.0). There was both an increased risk of supratherapeutic [OR=1.34 (95% CI 1.08-1.67)] and subtherapeutic levels [OR=1.40 (95% CI 1.08-1.83)] after first vaccination. In the high-intensity group (target INR 2.5-3.5), the risk of a supratherapeutic INR was 2.3 times higher after first vaccination [OR=2.29 (95% CI 1.22-4.28)] and 3.3 times higher after second vaccination [OR 3.25 (95% CI 1.06-9.97). Conclusion: BNT162b2 was associated with an immediate negative effect on anticoagulation control in patients treated with vitamin K antagonists, so it is advisable to monitor the INR short after vaccination, even in stable patients. Figure 1 Figure 1. Disclosures Kruip: Daiichi Sankyo: Research Funding; Bayer: Honoraria, Research Funding.

Tele-pharmacy Anticoagulation Clinic During COVID-19 Pandemic: Patient Outcomes

Introduction: It is well-established that clinical pharmacist-managed anticoagulation services achieve superior anticoagulation control, with a positive impact. At King Abdulaziz Medical City (KAMC), Riyadh, Saudi Arabia, the structure of anticoagulation management is a pharmacist-managed specialty service. With the current COVID-19 situation, measures were taken to assure the continuity of patient care by establishing tele-pharmacy anticoagulation clinics.Materials and Methods: This was a prospective study with patients prescribed anticoagulation and followed up for 3 months. Since establishing the anticoagulation virtual clinic in March 2020, 270 patients were recruited in the study. The data collected included age, gender, comorbidities, indication for anticoagulation, intended duration of treatment, warfarin dose, testing of International Normalized Ratio (INR), INR target, range of INR values, time INR that was within the therapeutic range (TTR), and complications of therapy (bleeding and/or bruises). The patients were asked to complete the pharmacist satisfaction survey (PSS) after their consultation to assess patient satisfaction with the new virtual consultation system. Linguistic and cultural validation was conducted for the questionnaire.Results: A total of 270 patients were included in the study. The mean percentage of overall INR values in the range was 59.39% ± 32.84, and the mean time with the overall INR was within the therapeutic range 57.81% ± 32.08. Thirty-one percent of the sample had good anticoagulation control (time in therapeutic range &gt;70%). The median satisfaction score was 32 (IQR 28–36) with a maximum score of 40.Conclusion: This is the first study to assess the tele-pharmacy anticoagulation clinic’s efficiency and patient satisfaction in Saudi Arabia during the COVID-19 pandemic. This type of consultation was as effective as face-to-face consultations. The study also highlighted that though the reduction in the cost of care was not substantial, there was a significant increase in resource (clinical pharmacist) utilization as a result of this model. The adoption of tele-pharmacy resulted in time savings for the clinical pharmacists who can be utilized in many other improvement projects in adult ambulatory clinics to ensure the delivery of better quality and safe patient care.

Assessment of Anticoagulation Control Association with Warfarin Knowledge and Demographic Features of Iranian Population

Background: Warfarin is the most commonly used oral anticoagulant for patients with atrial fibrillation, prosthetic heart valves, and deep vein thrombosis with a narrow therapeutic index. Due to the importance of patients’ adherence to treatment and also regular measurements of International normalized ratio (INR), this can have a significant impact on the quality of anticoagulation control. Objectives: The primary aim of this study was to assess the association between warfarin knowledge and time in therapeutic range (TTR) in patients on warfarin anticoagulation for at least 6 months who were referred to anticoagulation clinic in Rajaie Heart Center during 2016 - 2017. Methods: In this cross-sectional study, 620 patients who had been referred to the outpatient Rajaie Hospital anticoagulant clinic and had been taking warfarin for over six months were asked to fill two questionnaires named anticoagulation knowledge assessment (AKA) during a 12-week period. After obtaining the necessary permits, TTR (by Rosendal method) was calculated using the INR results of patients. Results: A total of 620 patients completed the questionnaire. The relation between warfarin knowledge and anticoagulation control was not significant. The mean age of the study population was 52.45 SD ± 14.01 years. This study showed a significant relationship between TTR, duration of warfarin usage (PV = 0.03) and the underlying cause of this usage (PV = 0.016). Conclusions: Prevention of chronic diseases is one of the most important priorities of the health care systems. Reduction in complications such as thrombosis and bleeding can be achieved by efforts to promote patient’s knowledge. By recognition of relation between warfarin knowledge and social and demographic indicators, patient’s education gap can be detected and also planned for dissolving. This study showed that although many of the patients visited in anticoagulation clinic have poor anticoagulation control, but a major part of them have good knowledge of warfarin usage.

SAMe-TT₂R₂ Score for Prediction of Anticoagulation Control in Thai Patients with Non-Valvular Atrial Fibrillation

Background: The quality of anticoagulation control is an important determination of thromboembolism and bleeding in patients with non-valvular atrial fibrillation. Previous trials have shown that SAMe-TT₂R₂ score could be used for prediction of anticoagulation control. Objective: To predict labile international normalized ratio (INR) by SAMe-TT₂R₂ score in Thai patients with non-valvular atrial fibrillation. Materials and Methods: The author retrospectively studied patients with non-valvularatrial fibrillation at Pranangklao Hospital between January 2019 and October 2020. Results: One hundred thirty patients were enrolled. The average ages of the patients were 67.5±10.2 years. The average SAMe-TT₂R₂ scores were 3.2±0.8 and the average CHA₂DS₂-VASc score was 3.3±1.4. Most patients had hypertension and dyslipidemia. Most patients were prescribed betablockers. Most patients had time in therapeutic range (TTR) lower than 65. The present study has shown that patients with SAMe-TT₂R₂ score of 3 or more has also had high proportion of labile INR with statical significance. The sensitivity, specificity, positive predictive value, and negative predictive value of different cut-offs of SAMe-TT₂R₂ score greater than 2 and SAMe-TT₂R₂ score when excluding race showed improvement of the sensitivity and specificity for prediction of labile INR. Conclusion: Labile INR was predicted by SAMe-TT₂R₂ score and the sensitivity and specificity increased in SAMe-TT₂R₂ score when excluding race. Keywords: SAMe-TT₂R₂ score; Non-valvular atrial fibrillation; Anticoagulation control