Evaluation of time in therapeutic range in anticoagulated patients: a single-center, retrospective, observational study

Comparison of anticoagulation control and outcomes between usual medical care and pharmacist-led anticoagulation service in ambulatory patients taking warfarin at tertiary hospital in Ethiopia: a quasi-experimental study

BACKGROUND

We aimed to compare anticoagulation control and outcomes between usual medical care (UMC) and pharmacist-led anticoagulation services (PLAS) in patients receiving warfarin at the Tikur Anbessa Specialized Hospital (TASH), Addis Ababa, Ethiopia.

METHODS

A quasi-experimental study was conducted, including 350 (66.7%) and 175 (33.3%) patients from the UMC and PLAS groups, respectively, from 525 patients. The time in therapeutic range (TTR) was determined using the Rosendaal method, with a TTR ≥ 65% set as the cut-off for optimal anticoagulation. The two-sample Wilcoxon rank-sum (Mann-Whitney U) test was used to compare continuous variables between groups. Categorical variables were compared between groups using Pearson's chi-square test or Fisher's exact test. Logistic regression and negative binomial regression analyses were conducted to identify the factors associated with suboptimal TTR and secondary outcomes, respectively, at the p values < 0.05, and 95% confidence interval (CI).

RESULTS

Compared with the UMC group, the patients in the PLAC group showed a significantly higher median (IQR) TTR [60.89% (43.5-74.69%) vs. 53.65% (33.92-69.14%), p < 0.001]. A significantly higher optimal TTR (≥ 65%) was achieved in the PLAC group (41.7% vs. 31.7%) than in the UMC group (p = 0.002). The odds of having a poor TTR were reduced by 43% (AOR = 0.57, 95% CI = 0.36-0.88, p = 0.01) among patients in the PLAC group compared to those in the UMC group. There were no statistically significant differences in the secondary outcomes between the groups, except for all-cause emergency visits (p = 0.003). The incidence of bleeding events decreased by 3% (IRR = 0.97, 95% CI = 0.96-0.99, p < 0.001) for every increase in INR monitoring frequency. The incidence of thromboembolic events increased by a factor of 15.13 (IRR = 15.13, 95% CI = 1.47-155.52, p = 0.02) among patients with a high-risk CHA2DS2-VASc score compared with those with a moderate score.

CONCLUSION

Patients in the PLAC group had a significantly higher median TTR than those in the UMC group did. There were no statistically significant differences in the secondary outcomes between the groups, except for fewer all-cause emergency department visits in the PLAC group.

Safety and Outcomes with Direct Oral Anticoagulants Versus Vitamin-K Antagonists in Chronic Thromboembolic Pulmonary Hypertension: A Systematic Review, Meta-Analysis, and Meta-Regression

Chronic thromboembolic pulmonary hypertension (CTEPH) is a subtype of pulmonary hypertension characterized by organized thrombi inside the pulmonary vasculature, leading to an increase in pulmonary artery pressure. CTEPH is seen in about 3-4% of patients with acute pulmonary embolism and is associated with poor outcomes. Apart from surgical intervention, lifelong anticoagulation is the mainstay of CTEPH management. Traditionally, CTEPH is managed with vitamin-K antagonists (VKA); however, direct oral anticoagulants (DOACs) are recently gaining popularity. However, the current literature comparing DOACs versus VKAs in CTEPH has inconsistent results. An electronic search of the major bibliographic databases was performed to retrieve studies comparing DOACs versus VKAs in CTEPH patients. For dichotomous outcomes, the odds ratio (ORs) with 95% confidence intervals (CI) were pooled using the DerSimonian and Laird random-effects model to generate forest plots. Statistical significance was considered at P < 0.05. Ten studies were included with 3936 patients (1269 in the DOAC group and 2667 in the VKA group). Treatment with DOAC was associated with no statistically significant difference in the risk of all-cause mortality (OR, 0.78; 95% CI, 0.35-1.71; P < 0.53), venous thromboembolism (OR, 1.19; 95% CI, 0.59-2.40; P = 0.63), major bleeding (OR, 0.68; 95% CI, 0.38-1.22; P = 0.20), and clinically relevant nonmajor bleeding (OR, 1.22; 95% CI, 0.80-1.86; P = 0.37). Our analysis demonstrates that DOACs are noninferior to VKAs in terms of their safety and outcomes profile in CTEPH. Further trials are needed to evaluate more robust evidence and to compare additional outcomes.

Decentralization and Virtualization of INR-based Anticoagulation Control During the COVID-19 Pandemic

OBJECTIVE

To investigate the effectiveness of the decentralization and virtualization of anticoagulation clinics just before and during the coronavirus disease 2019 (COVID-19) pandemic.

METHODS

We conducted a cohort study investigation at Prince Sultan Cardiac Clinics PSCC Qassim region, Saudi Arabia. To evaluate the effectiveness of the virtual coagulation clinic, we calculated the time in therapeutic range (TTR), Morisky score for adherence, and satisfaction. Demographics of the patients were analyzed to group patients based on their regions or districts to facilitate the visits. Thirteen different PHCs/Hospitals were allocated for decentralization based on patient density in that region. Intensive courses were provided for all general practitioners (GPs) regarding warfarin anticoagulation and point of care testing (POCT) using iSTAT. All appointments were scheduled by WhatsApp, with no more actual visits to the main center.

RESULTS

Among the included participants (n = 5616), 61.1% were females, 38.9% were males, and the mean age was 60.5 (18-85) years. The total number of clinic visits was 7303 per month, with an average of 1.3 visits per patient. Approximately 95% of the participants had a valvular indication to receive anticoagulation; of them, 55% underwent mitral valve replacement. Moreover, after the virtualization of the INR clinic, keeping INR levels within a therapeutic range was reported in 80% of patients. Regarding patient satisfaction, 90% of the total population was satisfied by the new experience.

CONCLUSION

Decentralization and virtualization of the INR clinic have similar TTR results if conducted properly.

Anticoagulation control, outcomes, and associated factors in long-term-care patients receiving warfarin in Africa: a systematic review

Background

Oral anticoagulation therapy with warfarin requires frequent monitoring level of anticoagulation by the international normalized ratio (INR). In Africa, studies that explore anticoagulation control, treatment outcomes, and associated factors are reported in various ways in long-term patients receiving warfarin therapy to generate concrete scientific evidence.

Methods

The literature search was conducted in PubMed, Cochrane Library, African Journal of Online databases, Google Scholar, and Google. An advanced search strategy was computed to retrieve relevant studies related to anticoagulation control and outcomes. Duplication, title and abstract screening, and full-text assessment were conducted in Covidence software. Study quality was assessed using the Joanna Briggs Institute Critical appraisal quality assessment tool. The systematic review is registered in PROSPERO (CRD42021260772) and performed based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guideline.

Results

Out of 298 identified articles, 18 articles were eligible for the final review and analysis. The mean of 39.4 ± 8.4% time in therapeutic range (TTR) (29.4 to 57.3%), 36.7 ± 11.5% TTR (range 25.2–49.7%) and 46% TTR (43.5–48.5%) was computed from studies that determined TTR by Rosendaal, direct and cross-section-of-the-files methods, respectively. In this review, the lowest percentage of TTR was 13.7%, while the highest was 57.3%. The highest percentage of patients (32.25%) who had TTR ≥ 65% was reported in Tunisia, but the lowest percentages were in Namibia (10%, TTR ≥ 65%) and Kenya (10.4%, TTR ≥ 70%). Most of the included studies (11 out of 18) used Rosendaal’s method while the direct method was employed by three studies. Generally, 10.4–32.3% of study participants achieved desired optimal anticoagulation level. Regarding secondary outcomes, 1.6–7.5% and 0.006–59% of patients experienced thromboembolic complications and bleeding events, respectively. Having chronic comorbidities, taking more than two drugs, and presence of medications that potentially interact with warfarin, and patient-related factors (patients aged < 50 years old, female gender, lower education level, smoking history) were the frequently reported predictors of poor anticoagulation therapy.

Conclusions

Oral anticoagulation control was suboptimal in patients taking warfarin as evidenced by low TTR in Africa. Therefore, there is an urgent need for further improving oral anticoagulation management services.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-022-00416-9.

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.

Anticoagulation Control, Outcomes, and Associated Factors in Patients with Atrial Fibrillation Receiving Warfarin at Tertiary Care Hospital in Ethiopia

Anticoagulation is the cornerstone in the prevention of stroke in atrial fibrillation. This study aimed at assessing the anticoagulation control and outcome and predictive factors in atrial fibrillation patients on warfarin therapy. A retrospective chart review was used to evaluate patients with atrial fibrillation who were on warfarin during two years follow up at the anticoagulation clinic of the hospital. The time in therapeutic range (TTR) was calculated using Rosendaal's method. Data were analyzed using SPSS software version 25. Univariable and multivariable analyses were computed to determine factors affecting TTR and bleeding events. We included 300 patients in this study. The mean percentage TTR was 42.03 ± 18.75. Only 38 (12.67%) patients achieved a TTR of above 65%. The average international normalized ratio (INR) testing frequency was 35 days (16.3-67.2 days). Taking 1 or 2 drugs along with warfarin was found to be better in achieving good TTR as compared to taking more than two drugs (p = .014). Having heart failure was associated with a 2.45 times odds of poor anticoagulation control (TTR< 65%) (p = .047). Male study participants were 2.53 times more likely of developing bleeding events than females (p = .009). Bleeding events were observed in 62 (20.67%) patients. Study participants, who didn't have Diabetic Mellitus and those not receiving aspirin were at lower odds developing bleeding events (AOR = .196; C.I. = .060-.638; p−.007 and AOR = .099; CI. = .024-.416; p−.02), respectively. In summary, the time spent in the therapeutic range was minimal in this population of patients with AF on warfarin managed at a hospital run anticoagulation clinic in Ethiopia. Moreover, the number of co-prescribed medications, and having heart failure were associated with poor TTR. Bleeding events were high and affected by male sex, having DM comorbidity, and using aspirin.

Required warfarin dose and time in therapeutic range in patients with diagnosed Nonalcoholic Fatty Liver Disease (NAFLD) or Nonalcoholic Steatohepatitis (NASH)

Warfarin has been widely used to treat thromboembolism. The effect of nonalcoholic fatty liver disease (NAFLD) or nonalcoholic steatohepatitis (NASH), on warfarin dosing remains unknown. This study aims to examine the effects of NAFLD/NASH on the average daily dose (ADD) of warfarin and the time in therapeutic range (TTR). This is a retrospective study utilizing an administrative data. We included patients with at least 2 months of warfarin dispensing and two subsequent consecutive INR measures. The ADD of warfarin to achieve therapeutic range INR levels, and TTR were compared between patients with and without NAFLD/NASH in four subgroups of patients accounting for the presence of obesity and diabetes. Generalized linear models (GLM) with Propensity score (PS) fine stratification were applied to evaluate the relative differences (RD) of warfarin ADD and TTR (>60%) in four subgroups. A total of 430 NAFLD/NASH patients and 38,887 patients without NAFLD/NASH were included. The ADD and TTR, were not significant in the overall cohort between those with and without NAFLD/NASH. However, GLM results in patients without diabetes or obesity (N = 26,685) showed a significantly lower warfarin ADD (RD: -0.38; 95%CI: -0.74–-0.02) and shorter TTR (OR: 0.71; 95%CI: 0.52–0.97) in patients diagnosed with NAFLD/NASH. The effects of NAFLD/NASH on warfarin dose or TTR were observed in patients without obesity and diabetes. Obesity and diabetes appear to be significant modifiers for the effects of NAFLD/NASH on warfarin dose and TTR.

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 >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 the quality of anticoagulation management with warfarin in a tertiary care center

OBJECTIVES

To evaluate the quality of an anticoagulation clinic in a tertiary hospital and identified factors affecting the time in the therapeutic range (TTR) and its relation to different complications. Methods: This single-center retrospective study conducted between March 2015 and June 2016 included 1914 patients receiving warfarin therapy. They were divided into 4 warfarin indication groups: non-valvular atrial fibrillation (AF) (n=403), valvular AF (n=227), prosthetic valves (n=700), and venous or pulmonary embolism (n=584).

RESULTS

The median age was 56 (25th, 75th percentiles: [45, 67]) years, and 53.2% were female. The median TTR was 0.52 (0.28, 0.76). Low hemoglobin (0.007) and high alkaline phosphatase (0.020) levels negatively affected the TTR. Venous thromboembolism (VTE) was associated with low TTRs. Minor bleeding occurred in 64 (3.35%), gastrointestinal bleeding in 14 (0.7%), and stroke in 41 (2.2%) patients, with no inter-group differences. The TTR was not associated with minor bleeding (odds ratio [OR]=0.49; p=0.09), gastrointestinal bleeding (OR=0.29; p=0.18), or stroke (OR=1.15; p=0.79).

CONCLUSION

Reflecting the real-life experience of anticoagulation control, our patients spend less than half the TTR within the INR. The low target TTR mandates the need to improve service quality and control factors affecting the TTR, including hemoglobin levels and regular visits for patients with VTE.

Evaluation of Warfarin Anticoagulation at University of Gondar Comprehensive Specialized Hospital, North-West Ethiopia

PURPOSE

To assess the quality of warfarin anticoagulation and its clinical outcomes on patients treated with warfarin at the University of Gondar comprehensive specialized hospital, North-west Ethiopia.

METHODS

We reviewed medical records of patients treated with warfarin between June 1, 2016, and May 30, 2018, at the University of Gondar comprehensive specialized hospital. The quality of anticoagulation was evaluated using the percentage of time spent in the therapeutic range. Data were entered into Statistical Product and Service Solutions (SPSS), version 20. Descriptive statistics were used to describe the socio-demographic and clinical characteristics of study participants. Multivariable logistic regression analysis was performed to identify independent predictors of quality of anticoagulation. Statistical significance was declared when the p-value was less than 0.05 at 95% confidence interval (CI).

RESULTS

From a total of 202 patients' charts reviewed, women accounted for 134 (67.3%). The mean participants' age was 44.33 years (±17.05years SD). The median time spent in the therapeutic range was 37.91 with an IQR of (0.00-65.86). More than two-third (143, (70.8%)) of participants had poor anticoagulation quality (time spent in the therapeutic range is less than 65%). Twenty-seven patients (13.4%) experienced adverse medication events of bleeding and thromboembolic events. Logistic regression analysis showed that potential medication interaction [p= 0.003 95% CI Adjusted odds ratio (AOR): 0.32 (0.152-0.689)] and presence of co-morbidity [p= 0.037 95% CI AOR: 0.70 (1.046-4.105)] were significantly associated with quality of anticoagulation.

CONCLUSION

The quality of warfarin anticoagulation at the University of Gondar comprehensive specialized hospital was poor. A strong effort is needed to improve the quality of anticoagulation. Patients who had other co-morbidity conditions and potentially interacting medication need special attention.

Satisfaction of Patients with Nonvitamin K Anticoagulants Compared to Vitamin K Antagonists: a Systematic Review and Meta-analysis

OBJECTIVE

 To undertake a systematic review and meta-analysis to assess the satisfaction of patients receiving nonvitamin K anticoagulants (NOACs), compared with vitamin K antagonists (VKAs).

METHODS

 We searched CENTRAL, MEDLINE, Embase, and Clinicaltrials.gov for randomized controlled trials (RCTs) and observational studies. Two reviewers screened, extracted, and appraised data independently. We pooled data using a random-effects model. Outcome included treatment satisfaction, which was assessed by scores of Duke Anticoagulation Satisfaction Scale (DASS), Anticlot Treatment Scale (ACTS), Perception of Anticoagulant Treatment Questionnaire 2 (PACT-Q2), or Treatment Satisfaction Questionnaire for Medication version II (TSQM-VII) and their domains reported with 95% confidence intervals (95% CIs). We followed MOOSE and PRISMA guidelines.

RESULTS

 We included four RCTs and 16 observational studies, enrolling 18,684 participants overall. Compared with VKAs, treatment with NOACs improved the ACTS Burdens score by 4.21 points (95% CI: 2.99-5.43, I ² = 95%, combined n = 6,180), and ACTS Benefits by 0.49 points (95% CI: 0.18-0.81, I ² = 85%, combined n = 6,171). Switching from VKAs to NOACs improved the ACTS Burdens score by 5.33 points (95% CI: 3.53-7.14, combined n = 3,097). Compared with VKAs, treatment with NOACs improved the TSQM-VII Global Satisfaction score by 6.86 points (95% CI: 3.00-10.73, combined n = 5,535).

CONCLUSION

 In patients with nonvalvular atrial fibrillation or venous thromboembolism, NOAC treatment is associated with greater satisfaction compared with VKAs. The switch from VKAs to NOACs was associated with improved patients' satisfaction. These effects were largely due to a lower degree of treatment burden with NOAC treatment.

Direct oral anticoagulants: a review on the current role and scope of reversal agents

New guideline recommendations prefer direct oral anticoagulants (DOACs) over warfarin in DOAC-eligible patients with atrial fibrillation and patients with venous thromboembolism. As expected with all antithrombotic agents, there is an associated increased risk of bleeding complications in patients receiving DOACs that can be attributed to the DOAC itself, or other issues such as acute trauma, invasive procedures, or underlying comorbidities. For the majority of severe bleeding events, the widespread approach is to withdraw the DOAC, then provide supportive measures and "watchful waiting" with the expectation that the bleeding event will resolve with time. However, urgent reversal of anticoagulation may be advantageous in patients with serious or life-threatening bleeding or in those requiring urgent surgery or procedures. Until recently, the lack of specific reversal agents, has affected the uptake of these agents in clinical practice despite a safer profile compared to warfarin in clinical trials. In cases of life-threatening or uncontrolled bleeding or when patients require emergency surgery or urgent procedures, idarucizumab has been recently approved for reversal of anticoagulation in dabigatran-treated patients and andexanet alfa for factor Xa inhibitor-treated treated patients. The current review summarizes the current clinical evidence and scope of these agents with the potential impact on DOAC use in clinical practice.

Anticoagulation with Warfarin: Roles of Adherence, Social Support and Illness Perception

OBJECTIVES

This study was aimed to determine (1) the associations between adherence to warfarin, social support, perception of illness, and demographic factors on the quality of international normalized ratios (INRs); as well as (2) the relationship between the patients' scores in the Malaysian medication adherence scale (MALMAS) and their current INRs.

METHOD

This cross-sectional survey was conducted from November 2017 to January 2018 at the warfarin clinic of Jerantut Hospital, Malaysia.

RESULTS

Some 58 participants were recruited, of whom 70.7% were diagnosed with atrial fibrillation (AF). Overall, 87.9% of the participants claimed adherence to their warfarin regimens. Patients with good-quality INR therapy were significantly older, had a higher median income and longer appointment durations. In terms of illness perception (IP), participants with good-quality INR therapyhad significantly lower scores in the identity, personal control, and consequence domains. Overall, the total scores for IP were significantly lower in the good-quality INR therapy. Meanwhile, the MALMAS scores were significantly lower in patients with sub-therapeutic current INR. However, there were no associations between warfarin adherence and perceived social support with current TTR.

CONCLUSION

Monitoring of demographic factors and IP's domains is vital since they were associated with quality of INR therapy. Meanwhile, the occurrence of sub-therapeutic current INR should raise suspicion of poor adherence in these patients. Overall, IP and MALMAS are useful tools that should be integrated into the patient care protocols.

Rivaroxaban in atrial fibrillation cardioversion: an update

Currently, atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, with a prevalence of about 2-3% in the general population, representing a powerful risk factor for stroke and systemic thromboembolism and increased mortality and morbidity. Restoration of sinus rhythm is an important treatment option in AF and has a high success rate, but there is the need for an effective anticoagulation strategy to reduce the risk of embolic events. Anticoagulation with vitamin K antagonists is often associated with failure to achieving effective international normalized ratio. In this setting, recent data have led to extended approval for rivaroxaban in clinical practice, because it is effective and safe in patients with AF undergoing cardioversion, avoiding additional health costs and related time loss, while improving patient satisfaction. The present report provides an overview of the main randomized controlled trial and the main real-life studies, documenting the use of rivaroxaban in patients with non-valvular AF who underwent the cardioversion procedure. Considering that novel non-vitamin K antagonist oral anticoagulants in left atrial appendage thrombi resolution is still unknown in the real-world practice, the main findings on the use of rivaroxaban in this setting are also discussed.

Maintenance dose of warfarin beyond time in therapeutic range for preventing vascular events

BACKGROUND

The quality of anticoagulation is closely associated with efficacy and safety in warfarin users. Although genetic polymorphisms have been related to warfarin dosages and vascular events(VE), genetic evaluations have not been recommended for all warfarin users. The aim is to evaluate the significance of the maintenance dose of warfarin (MDW) on VE, considering the time in therapeutic range (TTR).

METHODS

This retrospective study analyzed the data of patients who received warfarin for any reasons. A total of 11,835 patients with warfarin were divided into quartiles by MDW. We assessed TTR using the Rosendaal method and VE.

RESULTS

VE occurred in 9.1% of the warfarin users. The mean TTR level was 34.0 ± 25.7%, and the MDW was 3.38 ± 1.06 mg per day. Patients with VE were more likely to have a lower MDW and lower TTR levels. In moderate- or well-controlled TTR status, a lower MDW was significantly related to under-controlled anticoagulation and associated with higher risks of VE. Lower MDW had a higher risk of stroke or arterial/venous thromboembolism (Q1: OR, 1.57; 95% CI 1.25 to 1.96; Q2: OR, 1.40; 95% CI 1.12 to 1.75; Q3: OR, 1.35; 95% CI 1.08 to 1.68).

CONCLUSIONS

We suggest that patients with very low MDW might be at risk when using warfarin. Therefore, we propose that patients with a very low MDW might be alternatively considered for novel oral anticoagulants rather than warfarin.

The safety of NOACs in atrial fibrillation patient subgroups: A narrative review

AIM

Four non-vitamin K oral anticoagulants (NOACs) have been evaluated in clinical trials for the prevention of stroke in patients with atrial fibrillation (AF). Although each of the NOACs have been shown to be at least non-inferior to warfarin for efficacy and safety outcomes, controversy remains over the relative safety of each NOAC inpatient subgroups. This narrative review provides an overview of phase III data on NOAC trials for the prevention of stroke in AF, with a focus on reporting the safety of each agent in key patient subgroups based on age, gender, accumulated risk factors, and primary or secondary prevention of stroke.

METHODS

A comprehensive literature search was completed and, where data permit, analyses of phase III trials of the NOACs are presented for each patient subgroup.

RESULTS

Analyses of key safety outcomes from NOAC trials were completed using primary trial data, including major bleeding and all-cause mortality. The safety of NOACs was generally consistent and favourable compared with warfarin according to patient age, gender, previous history of stroke, and the presence of risk factors for stroke.

CONCLUSIONS

The safety of the NOACs compared with warfarin was generally favourable across different patient subgroups, including those perceived to be at "high risk" for adverse outcomes. However, certain NOACs may be preferable to warfarin in some subgroups, based on indirect analyses.

Non-vitamin K antagonist oral anticoagulants in elderly patients with atrial fibrillation: A systematic review with meta-analysis and trial sequential analysis

BACKGROUND

Elderly population is known to be associated with polymedication, comorbidities and altered drug pharmacokinetics. However, the most adequate oral anticoagulant, attending to its relative efficacy and safety, remains unclear.

METHODS

We searched for phase III randomized controlled trials (MEDLINE, Cochrane Library, SciELO collection and Web of Science) comparing novel non-vitamin K antagonist oral anticoagulants (NOACs) with Vitamin K antagonists (VKA) in the elderly population (≥75 years-old) in atrial fibrillation (AF). Risk ratios (RR) were calculated using a random effects model. Trial sequential analysis (TSA) was performed in statistically significant results to evaluate whether cumulative sample size was powered.

RESULTS

Four trials rendered data about elderly (≥75 years-old) and younger patients (<75 years-old) with AF. NOACs demonstrated a 30% significant risk reduction (RR 0.70, 95% CI: 0.61 to 0.80) in elderly patients compared to VKA, without heterogeneity across studies (I² = 0%). The TSA showed that cumulative evidence of this subgroup exceeded the minimum information size required for the risk reduction. In younger patients, VKA and NOACs shared a similar risk of stroke and systemic embolism (RR 0.97, 95% CI: 0.79 to 1.18). Regarding major bleeding risk in the elderly, the overall comparative risk of NOACs was not different from VKA (RR 0.91, 95% CI: 0.72 to 1.16; I² = 86%).

CONCLUSIONS

NOACs reduce significantly the risk of stroke and systemic embolism in elderly patients without increasing major bleeding events. The dimension of stroke risk reduction was significantly higher in the elderly than in younger adults.

INR Control of Patients with Mechanical Heart Valve on Long-Term Warfarin Therapy

BACKGROUND

Warfarin is an anticoagulant indicated for patients who had undergone mechanical heart valve(s) replacement (MHVR). In these patients, time in therapeutic range (TTR) is important in predicting the bleeding and thrombotic risks.

OBJECTIVE

This study aimed to describe the anticoagulation control of warfarin using TTR in patients with MHVR in a tertiary health care referral Center.

METHODS

Data were collected retrospectively by reviewing clinical notes of outpatients who attended international normalized ratio (INR) clinics in November 2015. Patients who had MHVR and who took warfarin were included. The data collected were demographics, relevant laboratory investigations, and patients' prior medical history. TTR was calculated using Rosendaal and traditional methods.

RESULTS

A total of 103 patients with MHVR were recruited. The mean age was 51.72 ± 13.97 years and 46.6% were male. A total of 54.4% had mitral valve replacement (MVR), whereas 26.2% had aortic valve replacement (AVR). The mean TTR calculated using the Rosendaal method was 57.1%. There was no significant difference among patients with AVR, MVR, and both valves (AMVR) in terms of TTR (AVR vs. MVR vs. AMVR, 62.94 ± 23.08, 54.12 ± 21.62, 57.63 ± 17.47; p = 0.213). The average dose of warfarin for all groups was approximately 3 mg/day. Moreover, MVR, AVR, and AMVR patients who had TTR (Rosendaal method) ≤60% were 58.9%, 37.0%, and 45.0%, respectively. Only 4.8% had minor bleeding, whereas none had stroke in the period of TTR determination.

CONCLUSIONS

Despite a majority of patients having <60% TTR, there were low incidences of bleeding and stroke events in this center. There were no factors found to be associated with INR control in this study.

A one year audit of patients with venous thromboembolism presenting to a tertiary hospital in Johannesburg, South Africa

Introduction

Given the growing burden of venous thromboembolism (VTE) worldwide and the paucity of data from the developing world, the aim of this study was to audit the characteristics, risk factors and length of hospital stay of patients with VTE presenting to a tertiary hospital emergency centre in Johannesburg, South Africa.

Methods

The study was a retrospective record review of all patients who presented with VTE to a tertiary academic emergency centre in Johannesburg, South Africa from 1 April 2012 to 30 March 2013.

Results

Venous thromboembolism was identified in 74 patients; 56 (75.7%) with isolated deep vein thrombosis, 13 (17.6%) with pulmonary embolism and five (6.8%) who had a concurrent deep vein thrombosis with pulmonary embolism. The median age of the patients was 40 years old (range 19–90). The female to male ratio was 2:1. HIV infection, tuberculosis and history of immobilisation were the most common risk factors. The median duration of hospital stay was 14 days (range 4–36). A therapeutic International Normalised Ratio at discharge was only reached in 36.5% of patients.

Conclusion

Venous thromboembolism presentation to the emergency centre is not common, but the risks associated with the morbidity and mortality related to it makes it important despite its relative scarcity. The prevalence of HIV infection amongst patients with VTE is concerning – not only related to the frequency of the pathology but also due to HIV not being factored into the common VTE risk stratification scores.

Outcomes associated with warfarin time in therapeutic range among US veterans with nonvalvular atrial fibrillation

BACKGROUND

Poor quality of warfarin control (time in therapeutic range [TTR] < 65%) can lead to increased risk of adverse events. The objective of this study was to examine the overall quality of international normalized ratio (INR) control and the association of TTR with clinical outcomes including stroke, major bleeding, and all-cause mortality among US warfarin users.

METHODS AND RESULTS

This retrospective observational cohort study utilized the US Veterans Affairs electronic medical records database (VA EMR). Patients with NVAF who newly initiated warfarin from 1 January 2005 to 31 December 2015 were grouped into two cohorts based on TTR <65% or ≥65%. TTR was computed from INR test results. Clinical outcomes assessed were stroke/systemic embolism (SE), hemorrhagic stroke, ischemic stroke, and major bleeding, defined based on hospitalization with those conditions as primary diagnosis, as well as all-cause mortality. Patients were followed from warfarin initiation to the first occurrence of an outcome or censoring. Propensity score weighted time-varying Cox regression was used to evaluate the risk of the clinical events. A total of 127,385 NVAF patients with mean TTR of 51% were included. TTR <65% was observed in 65% of patients. Mean CHA₂DS₂-VAS_C score (SD) was 2.9 (1.5) in the low TTR cohort and 2.7 (1.4) in the high TTR cohort. Patients with TTR <65% had a higher risk for any stroke/SE (HR: 1.57; 95% CI: 1.41-1.75), major bleeding (HR: 2.78; 95% CI: 2.55-3.03) and all-cause mortality (HR: 1.73; 95% CI: 1.67-1.79).

CONCLUSIONS

The observed quality of warfarin control in VA EMR suggests room for improvement given the association with elevated risk of adverse clinical outcomes.

Age is associated with time in therapeutic range for warfarin therapy in patients with atrial fibrillation

Background

Warfarin is the most prescribed oral anticoagulant used for preventing stroke in patients with atrial fibrillation. Time in the therapeutic range (TTR) has been accepted as the best method to evaluate the quality of warfarin therapy. The main aim of the present study was to evaluate the impact of variables on the time in the therapeutic range for warfarin therapy in patients with atrial fibrillation from a referral cardiovascular hospital.

Methods

This retrospective study included 443 patients were included (190 patients with age < 65 years and 253 patients with age ≥65 years) from 2011 to 2014 and TTR was computed according to Rosendaal's method.

Results

Patients with age ≥65 years had higher TTR value (67±22%) compared with patients with < 65 years (60±24%) (p = 0.004). In a linear regression model, only age ≥65 years emerged as a significant predictor of greater TTR values. In multivariate logistic regression model, the variable age ≥65 years was associated with higher OR for having a TTR higher than the median value (OR = 2.17, p < 0.001).

Conclusion

We suggest that the age influenced TTR through greater drug adherence. Strategies for increasing drug adherence might improve quality of warfarin anticoagulation.

Designing and Implementing an Electronic Patient Registry to Improve Warfarin Monitoring in the Ambulatory Setting

BACKGROUND

Warfarin requires individualized dosing and monitoring in the ambulatory setting for protection against thromboembolic disease. Yet in multiple settings, patients spend upwards of 30% of time outside the therapeutic range, subjecting them to an increased risk of adverse events. At an urban, publicly funded clinic, the electronic health record (EHR) would not support integration with extant warfarin management software, which led to the creation and implementation of an electronic patient registry and a complementary team-based work flow to provide real-time health-system-level data for warfarin patients.

METHODS

Creation of the registry, which began in August 2014, entailed use of an existing platform, which could interface with the outpatient EHR. The registry was designed to help ensure regular testing and monitoring of patients while enabling identification of patients and subpopulations with suboptimal management. The work flow used for the clinic's warfarin patients was also redesigned. An assessment indicated that the registry identified 341 (96%) of 357 patients actively seen in the clinic.

RESULTS

For the cohort of the 357 patients in the registry, the no-show rate decreased from 31% (preimplementation, August 2014-December 2014) to 21% (postimplementation, January 2015-November 2015). The ratio of visits to no-shows increased from 2.3 to 4.0 visits.

CONCLUSION

Design and implementation of an electronic registry in conjunction with a complementary work flow established an active tracking system that improved treatment monitoring for patients on anticoagulation therapy. Registry creation also facilitated assessment of the quality of care and laid the groundwork for ongoing evaluation and quality improvement efforts.

The efficacy and safety of direct oral anticoagulants vs traditional anticoagulants in cirrhosis

INTRODUCTION

The coagulopathy of cirrhosis is complex, placing patients at risk for both bleeding and thrombosis. Direct oral anticoagulants (DOACs) have equivalent or superior efficacy and safety as compared to vitamin K antagonists (VKAs); however, their efficacy and safety in liver cirrhosis has not been studied. To better define this, we evaluated outcomes of patients with cirrhosis prescribed DOACs compared to other anticoagulants at our center.

METHODS

Retrospective cohort study of patients with cirrhosis prescribed therapeutic anticoagulation over a 3-year period for thrombosis or prevention of stroke in patients with atrial fibrillation. The primary outcomes of interest were bleeding events and recurrent thrombosis or stroke.

RESULTS

During the study period, 27 patients with cirrhosis were prescribed a DOAC and 18 were prescribed VKA or low molecular weight heparin (LMWH). Both groups had similar total bleeding events (8 DOAC vs 10 other, P=.12). There were significantly less major bleeding episodes in the DOAC group (1 [4%] vs 5 [28%], P=.03). Recurrent thrombosis occurred in one patient receiving a DOAC (4%) and one patient (6%) receiving other anticoagulation (P=1.0).

CONCLUSIONS

Direct oral anticoagulant use in patients with cirrhosis may be as safe as traditional anticoagulants. Patients with cirrhosis at our center prescribed DOACs had less major bleeding events, while maintaining efficacy at preventing stroke or thrombosis.

Anticoagulation control among patients with nonvalvular atrial fibrillation: A single tertiary cardiac center experience

There is a limited knowledge about the predictors of anticoagulation control in patients with nonvalvular atrial fibrillation (NVAF). Furthermore, few reports addressed the role of time in therapeutic range (TTR) that could reflect the safety and efficacy of anticoagulation therapy. We aimed to assess factors that affect the quality of anticoagulation therapy utilizing TTR in patients with NVAF. A retrospective observational study was conducted for patients with NVAF who were maintained on warfarin >6 months at a tertiary cardiac care hospital. Patients were categorized according to the TTR status (≥65% vs. <65%). A total of 241 eligible patients were identified. A high-quality anticoagulation based on TTR values ≥65% was found in 157 (65.1%) patients; the remaining (34.9%) patients represented the low-quality anticoagulation group (TTR <65%). Demographics and clinical characteristics were comparable in the two TTR groups. Both groups were comparable in terms of warfarin dose and medications use. When compared to patients with high-quality anticoagulation, patients in the low-quality anticoagulation group were more likely to seek outpatient warfarin clinic visits more frequently (22.3 ± 5.5 vs. 18 ± 4.4, P = 0.001) and to have higher rate of polypharmacy (57.1% vs. 42%, P = 0.03). Of note, patients in both groups had similar major bleeding events (P = 0.41). After adjusting for age and sex, polypharmacy use was a predictor of poor coagulation control (odds ratio = 1.89, 95% confidence interval: 1.03–3.33; P = 0.03). In NVAF patients, TTR is generally high in our cohort. Patients with polypharmacy and frequent clinic visits have lower TTR. High-quality oral anticoagulation could be achieved through optimizing TTR without a significant risk of major bleeding.

Evaluation of a pharmacogenetic-based warfarin dosing algorithm in patients with low time in therapeutic range - study protocol for a randomized controlled trial

Background

Time in therapeutic range (TTR) is a measurement of quality of warfarin therapy and lower TTR values (<50%) are associated with greater risk of thromboembolic and bleeding events. Recently, we developed a pharmacogenetic-based warfarin dosing algorithm specifically calibrated for a Brazilian patient sample. The aims of this study are: to evaluate the impact of a genetic-based algorithm, compared to traditional anticoagulation, in the time to achieve the therapeutic target and in TTR percentage; and to assess the cost-effectiveness of genotype-guided warfarin dosing in a specific cohort of patients with low TTR (<50%) from a tertiary cardiovascular hospital.

Methods/design

This study is a randomized controlled trial in patients (n = 300) with atrial fibrillation with TTR < 50%, based on the last three INR values. At the first consultation, patients will be randomized into two groups: TA group (traditional anticoagulation) and PA group (pharmacogenetic anticoagulation). For the first group, the physician will adjust the dose according to current INR value and, for the second group, a pharmacogenetic algorithm will be used. At the second, third, fourth and fifth consultations (with an interval of 7 days each) INR will be measured and, if necessary, the dose will be adjusted based on guidelines. Afterwards, patients who are INR stable will begin measuring their INR in 30 day intervals; if the patient’s INR is not stable, the patient will return in 7 days for a new measurement of the INR. Outcomes measures will include the time to achieve the therapeutic target and the percentage of TTR at 4 and 12 weeks. In addition, as a secondary end-point, pharmacoeconomic analysis will be carried out. Ethical approval was granted by the Ethics Committee for Medical Research on Human Beings of the Clinical Hospital of the University of São Paulo Medical School.

Discussion

This randomized study will include patients with low TTR and it will evaluate whether a population-specific genetic algorithm might be more effective than traditional anticoagulation for a selected group of poorly anticoagulated patients.

Trial registration

ClinicalTrials.gov, NCT02592980. Registered on 29 October 2015.

Is the time in therapeutic range using the ratio of tests equivalent to the Rosendaal method?

The percentage of time in therapeutic range (TTR) is a measure of anticoagulation quality with vitamin K antagonists (VKAs). The method most commonly used in clinical trials is the Rosendaal TTR. However, the application of this method in daily practice for clinical decision lacks appropriate instruments. We aimed to evaluate the percentage of tests within the target international normalized ratio (INR) (tests ratio) as a surrogate of Rosendaal TTR. We performed an observational and retrospective study to evaluate the TTR according to the Rosendaal method and tests ratio. We included all outpatients who attended the cardiology anticoagulation clinic of a Portuguese hospital (2011-2013), whose target INR was 2.0-3.0. Three hundred and seventy-seven VKA-treated patients followed for a mean 1.3 years were evaluated. Rosendaal methold and tests ratio significantly correlated (Rho Spearman 0.88, P < 0.001), but the Bland-Altman plot evaluation showed a clinically relevant data dispersion [95% confidence interval (95% CI) -12.9 to 23.1] around a mean difference in TTR -5.1% using the tests ratio method. The linear regression Passing-Bablok confirmed the existence of significant data dispersion and systematic differences. The tests ratio less than 60% had a sensitivity of 91.6%, specificity of 72.3%, positive predictive value (PPV) of 72.2% and negative predictive value (NPV) of 91.6%, for the diagnosis of patients inadequately anticoagulated (Rosendaal TTR <60%). Tests ratio had a c-statistics of 0.94 (95% CI 0.91-0.96). Number of tests in 6 months had a c-statistics of 0.70 (95% CI 0.65-0.75). Tests ratio underestimated TTR in 5% and was not considered equivalent to Rosendaal TTR due to the high variability between methods. Nevertheless, the use of tests ratio less than 60% may be a reasonable option to detect inadequate anticoagulation, as it is a sensitive method and excluded most of the patients with adequate control.