Anticoagulation patient self-monitoring in the United States: considerations for clinical practice adoption

The Relationship Between Signature Time and Functional Health Literacy: Results from a Prospective Study of an Urban Low-Income Population Receiving Long-Term Anticoagulation

INTRODUCTION

Low health literacy (HL) is consistently associated with worse health outcomes. Routine clinical screening with available instruments is impractical because of added time and effort. Prior findings suggested that signature time may be a reliable alternative measure of HL among general medicine patients.

METHODS

Our aim was to assess the screening performance of signature time and explore optimal thresholds for identifying patients with limited HL in a chronically anticoagulated population. English-speaking patients receiving long-term anticoagulation therapy were recruited. HL was assessed using the Short Test of Functional Health Literacy in Adults (STOFHLA). Signature time was measured using a stopwatch. Logistic regression models and receiver-operating characteristic (ROC) curves were used to evaluate the association and accuracy of signature time compared to HL, respectively.

RESULTS

Of 139 enrolled patients, mean age was 60.1 years, 70.5% were African-American, 48.9% reported < $25,000 income, and 27.3% had marginal or inadequate HL. Overall, median time to sign was 6.1 s. Signature time was longest with inadequate HL (median 9.5 s) compared to adequate HL (5.7 s; p < 0.01). Longer signature time was significantly associated with lower HL after adjusting for age and education (aOR 0.77, 95% CI: 0.68-0.88, p < 0.01). Signature time demonstrated high accuracy (area under the curve [AUC] > 0.8) in identifying HL levels. Thresholds of 5.1 s and 9.0 s showed appropriate screening performance in distinguishing patients with adequate vs. marginal and marginal vs. inadequate HL, respectively.

CONCLUSION

Signature time demonstrated strong screening performance and may offer a quick and practical approach to assessing HL among patients receiving long-term anticoagulation management.

[Comparison of Various Regimens of Antithrombotic Therapy in Patients With Valvular Heart Disease and Coronary Artery Disease After Surgical and Interventional Interventions]

AIM

To evaluate the postoperative incidence of bleeding, incidence of thromboembolic complications, and all-cause mortality in patients with valvular heart disease and ischemic heart disease (IHD) associated with various regimens of the antithrombotic treatment during one year after surgery.

MATERIAL AND METHODS

This study included 271 patients with valvular heart disease and IHD after heart valve replacement and myocardial revascularization from 2009 through 2018. However, during the follow-up period (12 months), contact with 12 patients was lost, and therefore these patients were excluded from the study. Further analysis included 259 patients. Coronary artery bypass grafting (CABG) in combination with heart valve intervention was performed in 217 (83.8 %) patients, and percutaneous coronary interventions (PCIs) were performed in 42 (16.2 %) patients. There were 197 (72.7 %) male participants; median age was 64.0 [58.0; 67.5] years. The patients were divided into two groups. Group 1 consisted of 113 patients who received postoperative dual antithrombotic therapy (DAT) with acetylsalicylic acid (ASA)/clopidogrel+vitamin K antagonist (VKA). Group 2 included 146 patients receiving postoperative triple antithrombotic therapy (TAT) with ASA+clopidogrel+VKA. Follow-up duration was 12 months after surgery. Due to significant intergroup differences in major clinical anamnestic data, the data were adjusted using pseudo-randomization (Propensity Score Matching, PSM). In result, 109 patients were selected for each group.

RESULTS

The incidence of adverse hemorrhagic outcomes was significantly higher in the group treated with TAT than with DAT. Minor bleedings were observed in 19 (17.4 %) vs. 8 (7.3 %) cases; moderate, clinically significant bleedings in 16 (14.7 %) vs. 6 (5.5 %) cases; and the total number of bleedings was 35 (32.1 %) vs. 14 (12.8 %; p=0.02, p=0.02, and р=0.001, respectively). Comparing the incidence of major bleedings did not show and significant intergroup differences (p=1.000). The incidence rate of any bleeding during the follow-up period was 32.1 % in patients treated with TAT (n=109) and 12.8 % in patients treated with DAT (n=109; p=0.005). The incidence of no bleeding during one year after surgery was 87 % in the DAT treatment group and 67 % in the TAT treatment group (p=0.005). The incidence of secondary endpoints, including ischemic stroke, myocardial infarction, prosthetic valve thrombosis, and death, was statistically non-significant.

CONCLUSION

Administration of DAT vs. TAT after heart valve replacement and myocardial revascularization significantly decreases the incidence of any bleedings in the absence of significant differences in the incidence of thromboembolic events and mortality.

Barriers to self-monitoring implementation in the oral anticoagulated population: A qualitative study

AIM

This study aimed to explore and understand the barriers perceived by Italian nurses to adopting self-monitoring for managing oral anticoagulation in real-life settings.

BACKGROUND

Barriers to self-monitoring implementation for managing oral anticoagulation have been poorly described.

DESIGN

The study had a qualitative descriptive and exploratory design with a hybrid approach.

METHODS

A literature review was conducted to identify a priori barriers (deductive approach), while a small and semi-structured focus group discussion was performed to explore the contextual barriers experienced by Italian nurses (inductive approach). A classic content analysis technique was adopted. Data were collected in 2019.

FINDINGS

Two main categories were identified. Organizational barriers referred to the lack of inter-professional collaboration and health-care system strategies to provide clinical pathways for self-monitoring. Individual barriers encompassed professional characteristics (e.g. university background, professional knowledge, continuum education and accountability/responsibility) and patient characteristics (e.g. patient health literacy and knowledge, engagement/empowerment and educational programmes). Finally, unwarranted clinical variation in oral anticoagulation management arose as a barrier determined by organizational and individual elements.

CONCLUSIONS

The results of this study pointed out an urgent public health issue in addressing barriers influencing self-monitoring practice and in sustaining care models that might enhance the quality improvement of self-monitoring for managing oral anticoagulation.

Association between transportation barriers and anticoagulation control among an inner-city, low-income population: A prospective observational cohort study

Background

Anticoagulation with warfarin represents a transportation-sensitive treatment state. Transportation barrier is a common reason for not using health care services.

Objective

To assess the association between transportation barriers to anticoagulation clinic and anticoagulation control (AC) among an inner-city, low-income population.

Patients/Methods

Adults expected to be on chronic warfarin therapy were recruited from an ambulatory anticoagulation clinic. Participants completed a validated questionnaire that assessed transportation barriers to clinic, defined as self-reported trouble getting transportation to a clinic and a composite score of the presence of transportation barriers. Suboptimal AC was defined as time in therapeutic range (TTR) <60% over 6 months. Prevalence ratios with 95% confidence intervals (CIs), adjusted for age, sex, and annual household income, described the association of transportation trouble and barriers with AC.

Results

Of 133 participants, 42.9% had suboptimal AC. Mean age was 60.4 (SD, 13.6) years, and the majority of participants were women (62.2%). Participants with transportation trouble were more likely to report being disabled/unable to work (63.6%) and annual household income <$15 000 (45.5%). Mean TTR was significantly lower for participants with transportation trouble compared to those without (53.8% [SD, 24.7%] vs 64.7% [SD, 25.0%]; P = .03). Participants reporting transportation trouble or at least one transportation barrier were 1.60 (95% CI, 1.07-2.39) and 1.68 (95% CI, 1.01-2.80) times more likely, respectively, to have suboptimal AC compared to those without.

Conclusion

Inner-city, low-income individuals with transportation barriers were more likely to have suboptimal AC. Further research is warranted to evaluate the impact of alleviating patient-specific transportation barriers on anticoagulation outcomes.

Characteristics of software used in self-management of vitamin K antagonist therapy: A systematic review

INTRODUCTION AND GOAL

Currently, 1-2% of the population in developed countries are under treatment with oral anticoagulants. An appropriate strategy to deal with this increase in demand of treatment with oral anticoagulants and to manage the costs is the transfer of part or all of the responsibility for managing treatment to the patients. The use of information technology, particularly electronic health software, can be an appropriate method to improve the quality of self-management of treatment with these drugs. Therefore, this systematic review investigated studies that discuss the characteristics of electronic health software in self-management of oral anticoagulation therapy.

METHOD

A systematic review based on PRISMA protocol was conducted. In this study, articles were investigated that were in English. Articles existing in Cochrane, EMBASE and PubMed databases were searched up to 14 May 2017. Then, articles searched through Google Scholar were added to this study.

FINDINGS

The common characteristics used in most software included 'encryption in exchanging information', having an 'instruction module' and 'being Android-based'. In terms of functionality, 'communication between the patient and healthcare team' existed in most of the software.

CONCLUSION

The results of the study showed that the accuracy of administration of the dose of the drug using computer to reach a target international normalized ratio level was not less than those administered with experienced medical staff. In addition, the results indicated that important characteristics of the software include encryption in exchanging information, instruction module and Android-based instruction module. The most important characteristic was the interaction between the patient and the healthcare team.

Individual and monitoring centre influences upon anticoagulation control of AF patients on warfarin: A longitudinal multi-centre UK-based study

OBJECTIVES

Time within therapeutic INR range (TTR) predicts benefits/risk of warfarin therapy. Identification of individual- and centre-related factors that influence TTR, and addressing them to improve anticoagulation control, are important. This study examined the impact of individual and centre-related factors upon long-term anticoagulation control in atrial fibrillation patients in seven UK-based monitoring services.

METHODS

Data between 2000 and 2014 on 25 270 patients (equating to 203 220 patient years) [18 120 (71.7%) in general practice, 2348 (9.3%) in hospital-based clinics and 4802 (19.0%) in domiciliary service] were analysed.

RESULTS

TTR increased with increasing age, peaking around 77% at 70-75 years, and then declined, was lower in females than males, and in dependent home-monitored patients than those attending clinic (P < 0.0001). TTR, number of dose changes and INR monitoring events and the probability of TTR ≤ 65%, differed across the centres (P < 0.0001).

CONCLUSIONS

Although all the participating centres ostensively followed a standard dosing algorithm, our results indicate that variations in practice do occur between different monitoring sites. We suggest feedback on TTR for individual monitoring sites gauged against the average values reported by others would empower the individual centres to improve quality outcomes of anticoagulation therapy by identifying and adjusting contributory factors within their management system.

Bleeding Rate After Tooth Extraction in Patients Under Oral Anticoagulant Therapy

OBJECTIVES

The aim of this single-cohort prospective study was to evaluate the risk of adverse outcomes after tooth extraction in patients suffering from cardiovascular disorders and under oral anticoagulant therapy with an international normalized ratio within the value of 3.0.

METHODS

Two hundred ninety-three patients (mean age of 58.7 years) were enrolled and 560 tooth extractions were performed. Fresh extraction sockets were treated with collagen tablets and sutures. The risk of increased bleeding rate was evaluated for type of drug therapy (acenocoumarol or warfarin), type of cardiovascular diseases, and number of tooth extractions. Level of significance was set at 0.05.

RESULTS

The overall bleeding event rate was 6.8%. Among patients who had bleeding events, 4 suffered from valvular disorders, whereas 11 suffered from arrhythmias (8) or cardiomyopathies (3). The remaining 5 patients had a history of cardiomyopathy and arrhythmia.The bleeding events in patients who had more than 2 tooth extractions were significantly higher than those observed in patients who had only 1 tooth extraction (P <0.05).

CONCLUSION

Patients who received more than 2 tooth extractions, who were under treatment with acenocoumarol, and who suffered from multiple cardiovascular diseases were at high risk for bleeding events.

The patients' perspective of international normalized ratio self-testing, remote communication of test results and confidence to move to self-management

AIMS AND OBJECTIVES

To elicit the perceptions of patients, who self-tested their international normalized ratio and communicated their results via a text or phone messaging system, to determine their satisfaction with the education and support that they received and to establish their confidence to move to self-management.

BACKGROUND

Self-testing of international normalized ratio has been shown to be reliable and is fast becoming common practice. As innovations are introduced to point of care testing, more research is needed to elicit patients' perceptions of the self-testing process.

DESIGN

This three site study used a cross-sectional prospective descriptive survey.

METHODS

Three hundred and thirty patients who were prescribed warfarin and using international normalized ratio self-testing were invited to take part in the study. The anonymous survey examined patient profile, patients' usage, issues, perceptions, confidence and satisfaction with using the self-testing system and their preparedness for self-management of warfarin dosage.

RESULTS

The response rate was 57% (n = 178). Patients' confidence in self-testing was high (90%). Patients expressed a high level of satisfaction with the support received, but expressed the need for more information on support groups, side effects of warfarin, dietary information and how to dispose of needles. When asked if they felt confident to adjust their own warfarin levels 73% agreed. Chi-squared tests for independence revealed that none of the patient profile factors examined influenced this confidence. The patients cited the greatest advantages of the service were reduced burden, more autonomy, convenience and ease of use. The main disadvantages cited were cost and communication issues.

CONCLUSION

Patients were satisfied with self-testing. The majority felt they were ready to move to self-management.

RELEVANCE TO CLINICAL PRACTICE

The introduction of innovations to remote point of care testing, such as warfarin self-testing, needs to have support at least equal to that provided in a hospital setting.

INR Stability, Clinical Importance, and Predictors in Patients With Atrial Fibrillation and Venous Thromboembolism Receiving Vitamin K Antagonists

Objective: Compare and contrast systematic reviews/meta-analyses assessing the time in the therapeutic range (TTR) for vitamin K antagonists (VKAs), clinical impact, and predictors. Data Sources: OVID MEDLINE search (1980-June 1, 2016) using the terms “vitamin K antagonist or warfarin” and “systematic review or meta-analysis” with backwards citation tracking from procured articles. Study Selection and Data Extraction: Search results were limited to systematic reviews assessing TTR with VKAs in patients with atrial fibrillation (AF) or venous thromboembolism (VTE). Data Synthesis: Six systematic reviews assessed TTR (4 in AF, 2 in VTE), and 3 of those assessed control at the time of a thrombotic or bleeding event (2 in AF, 1 in VTE). In patients on VKAs, greater TTR is correlated with fewer thromboembolic events and bleeding complications. VKA naïve patients have a harder time maintaining TTR than those with a previous knowledge of the likely therapeutic dose. Patients in the United States spend less TTR than those in other countries. Randomized clinical trials and anticoagulation clinics achieve greater TTR than those treated outside of these settings. The overall TTR has not improved from the first systematic reviews to the newest ones even though they were conducted 10 years apart and contained many new studies. Also, TTR in AF and VTE is similar. Conclusions: TTR is an important metric of VKA efficacy and safety and needs to be optimized. Many factors such as being VKA naïve can compromise TTR, and the use of anticoagulation clinics to optimize therapy is an important approach.

US Emergency Department Visits for Outpatient Adverse Drug Events, 2013-2014

Importance

The Patient Protection and Affordable Care Act of 2010 brought attention to adverse drug events in national patient safety efforts. Updated, detailed, nationally representative data describing adverse drug events can help focus these efforts.

Objective

To describe the characteristics of emergency department (ED) visits for adverse drug events in the United States in 2013-2014 and describe changes in ED visits for adverse drug events since 2005-2006.

Design, Setting, and Participants

Active, nationally representative, public health surveillance in 58 EDs located in the United States and participating in the National Electronic Injury Surveillance System-Cooperative Adverse Drug Event Surveillance project.

Exposures

Drugs implicated in ED visits.

Main Outcomes and Measures

National weighted estimates of ED visits and subsequent hospitalizations for adverse drug events.

Results

Based on data from 42 585 cases, an estimated 4.0 (95% CI, 3.1-5.0) ED visits for adverse drug events occurred per 1000 individuals annually in 2013 and 2014 and 27.3% (95% CI, 22.2%-32.4%) of ED visits for adverse drug events resulted in hospitalization. An estimated 34.5% (95% CI, 30.3%-38.8%) of ED visits for adverse drug events occurred among adults aged 65 years or older in 2013-2014 compared with an estimated 25.6% (95% CI, 21.1%-30.0%) in 2005-2006; older adults experienced the highest hospitalization rates (43.6%; 95% CI, 36.6%-50.5%). Anticoagulants, antibiotics, and diabetes agents were implicated in an estimated 46.9% (95% CI, 44.2%-49.7%) of ED visits for adverse drug events, which included clinically significant adverse events, such as hemorrhage (anticoagulants), moderate to severe allergic reactions (antibiotics), and hypoglycemia with moderate to severe neurological effects (diabetes agents). Since 2005-2006, the proportions of ED visits for adverse drug events from anticoagulants and diabetes agents have increased, whereas the proportion from antibiotics has decreased. Among children aged 5 years or younger, antibiotics were the most common drug class implicated (56.4%; 95% CI, 51.8%-61.0%). Among children and adolescents aged 6 to 19 years, antibiotics also were the most common drug class implicated (31.8%; 95% CI, 28.7%-34.9%) in ED visits for adverse drug events, followed by antipsychotics (4.5%; 95% CI, 3.3%-5.6%). Among older adults (aged ≥65 years), 3 drug classes (anticoagulants, diabetes agents, and opioid analgesics) were implicated in an estimated 59.9% (95% CI, 56.8%-62.9%) of ED visits for adverse drug events; 4 anticoagulants (warfarin, rivaroxaban, dabigatran, and enoxaparin) and 5 diabetes agents (insulin and 4 oral agents) were among the 15 most common drugs implicated. Medications to always avoid in older adults according to Beers criteria were implicated in 1.8% (95% CI, 1.5%-2.1%) of ED visits for adverse drug events.

Conclusions and Relevance

The prevalence of emergency department visits for adverse drug events in the United States was estimated to be 4 per 1000 individuals in 2013 and 2014. The most common drug classes implicated were anticoagulants, antibiotics, diabetes agents, and opioid analgesics.

Vitamin K antagonist use: evidence of the difficulty of achieving and maintaining target INR range and subsequent consequences

Vitamin K antagonists (VKAs) are effective oral anticoagulants that are titrated to a narrow therapeutic international normalized ratio (INR) range. We reviewed published literature assessing the impact of INR stability - getting into and staying in target INR range - on outcomes including thrombotic events, major bleeding, and treatment costs, as well as key factors that impact INR stability.

A time in therapeutic range (TTR) of ≥65 % is commonly accepted as the definition of INR stability. In the real-world setting, this is seldom achieved with standard-of-care management, thus increasing the patients’ risks of thrombotic or major bleeding events. There are many factors associated with poor INR control. Being treated in community settings, newly initiated on a VKA, younger in age, or nonadherent to therapy, as well as having polymorphisms of CYP2C9 or VKORC1, or multiple physical or mental co-morbid disease states have been associated with lower TTR. Clinical prediction tools are available, though they can only explain <10 % of the variance behind poor INR control.

Clinicians caring for patients who require anticoagulation are encouraged to intensify diligence in INR management when using VKAs and to consider appropriate use of newer anticoagulants as a therapeutic option.

Comparing Patient and Physician Risk Tolerance for Bleeding Events Associated with Anticoagulants in Atrial Fibrillation-evidence from the United States and Japan

OBJECTIVES

Atrial fibrillation (AF) is a factor in the development of thrombi that can lead to ischemic strokes. Anticoagulants are crucial in preventing strokes among patients with AF but are associated with bleeding risks. Recent studies have shown that despite anticoagulants' efficacy in stroke prevention, many patients with AF receive subtherapeutic levels of anticoagulation because of concerns about bleeding. Of particular interest is to quantify the perceived relative importance of treatment-related benefits and risks and how these perceptions vary between patients and physicians in different countries.

METHODS

Patients' and physicians' preferences were elicited using a discrete-choice experiment. We evaluated disagreements in preferences for the benefits and risks of anticoagulants.

RESULTS

A total of 186 patients with AF and 107 physicians in the United States completed the survey. In Japan, 152 patients and 164 physicians completed the same survey. Japanese patients were relatively less averse than US patients to bleeding risks. Physicians in both countries did not distinguish between nondisabling and disabling strokes. US patients were less tolerant than physicians of nonmajor clinically relevant bleeding risk when this risk was a consequence of preventing nondisabling strokes. Japanese patients were generally more tolerant than physicians of bleeding risks when the risks were consequences of preventing both nondisabling and disabling strokes.

CONCLUSIONS

Overall, preferences for anticoagulant benefits and risks were not statistically different between patients and physicians in the United States, nor were there differences in preferences for different stroke risks between physicians in the United States and Japan; however, preferences were different between patients and physicians in Japan.

Quality of vitamin K antagonist control and outcomes in atrial fibrillation patients: a meta-analysis and meta-regression

BACKGROUND

Atrial fibrillation (AF) patients frequently require anticoagulation with vitamin K antagonists (VKAs) to prevent thromboembolic events, but their use increases the risk of hemorrhage. We evaluated time spent in therapeutic range (TTR), proportion of international normalized ratio (INR) measurements in range (PINRR), adverse events in relation to INR, and predictors of INR control in AF patients using VKAs.

METHODS

We searched MEDLINE, CENTRAL and EMBASE (1990-June 2013) for studies of AF patients receiving adjusted-dose VKAs that reported INR control measures (TTR and PINRR) and/or reported an INR measurement coinciding with thromboembolic or hemorrhagic events. Random-effects meta-analyses and meta-regression were performed.

RESULTS

Ninety-five articles were included. Sixty-eight VKA-treated study groups reported measures of INR control, while 43 studies reported an INR around the time of the adverse event. Patients spent 61% (95% CI, 59-62%), 25% (95% CI, 23-27%) and 14% (95% CI, 13-15%) of their time within, below or above the therapeutic range. PINRR assessments were within, below, and above range 56% (95% CI, 53-59%), 26% (95% CI, 23-29%) and 13% (95% CI, 11-17%) of the time. Patients receiving VKA management in the community spent less TTR than those managed by anticoagulation clinics or in randomized trials. Patients newly receiving VKAs spent less TTR than those with prior VKA use. Patients in Europe/United Kingdom spent more TTR than patients in North America. Fifty-seven percent (95% CI, 50-64%) of thromboembolic events and 42% (95% CI, 35 - 51%) of hemorrhagic events occurred at an INR <2.0 and >3.0, respectively; while 56% (95% CI, 48-64%) of ischemic strokes and 45% of intracranial hemorrhages (95% CI, 29-63%) occurred at INRs <2.0 and >3.0, respectively.

CONCLUSIONS

Patients on VKAs for AF frequently have INRs outside the therapeutic range. While, thromboembolic and hemorrhagic events do occur patients with a therapeutic INR; patients with an INR <2.0 make up many of the cases of thromboembolism, while those >3.0 make up many of the cases of hemorrhage. Managing anticoagulation outside of a clinical trial or anticoagulation clinic is associated with poorer INR control, as is, the initiation of therapy in the VKA-naïve. Patients in Europe/UK have better INR control than those in North America.

[Anticoagulation clinics, present situation and future perspectives]

There are several modalities to monitor oral anticoagulant therapy, namely: monitoring by a secondary care specialist in the hospital setting; monitoring by the general practitioner/ family doctor in the primary care setting; monitoring by private laboratories of clinical analysis; self-monitoring with point-of-care devices. In Portugal, the most frequent modality is still the hospital monitoring/anticoagulation clinics, although monitoring in the primary care/routine medical care setting has began to be implemented in some areas of the country since five years ago. Anticoagulation clinics are still actually the organizations that optimize better the clinical and laboratorial follow up of the patients anticoagulated with warfarin. In 2011, anticoagulation control quality was evaluated, in the setting of an anticoagulation clinic (Santo António Hospital, Porto Hospital Center) by determining the proportion of INRs within the therapeutic range. The evaluation focused ambulatory patients, during a period of two months, corresponding to 1067 controls from 687 patients (mean age: 69±13 years; 54%, n=567, female gender). 71% of controls (n=756) were within the therapeutic range. 27% of controls were outside the therapeutic range, after exclusion of patients with programmed surgery or invasive proceedings. 13.8% of controls were below the therapeutic range and 8.6% (n=92) of the latter had INR ≤ 1.5. Above therapeutic range were 13.2% (n=139), from which 4.4% (n=46) had an INR between 5-8 and 0.3% (n=4) an INR ≥ 8. The group of primary care Health Centers (Portuguese acronym ACES) of the Baixo Tâmega region conducted, also in 2011, an evaluation of the anticoagulant control quality, by determining the proportion of INRs within the therapeutic range. The results were similar to those found in the anticoagulation clinic of the Hospital de Santo António which shows that the quality of monitoring in the primary care setting can have the same quality of the anticoagulation clinics monitoring. The introduction of the new oral anticoagulants, that don't require laboratorial monitoring constitutes a challenge. In Portugal, there is no experience yet to respond to the question if, in this new context, the anticoagulation clinics will be fundamental for the registration of patients, the evaluation of the hemorrhagic risk, the clinical follow up or the evaluation of the adherence to therapy.

The association of health literacy with time in therapeutic range for patients on warfarin therapy

Patients on warfarin therapy need to achieve and maintain anticoagulation control in order to experience the benefits of treatment while minimizing bleeding risk. Low health literacy skills may hinder patients' ability to use and adhere to warfarin in a safe and effective manner. The authors conducted this study to evaluate the relationship between health literacy and anticoagulation control among patients on chronic warfarin therapy. Participants were recruited from 2 diverse anticoagulation clinics in North Carolina. Time in therapeutic range (TTR) for warfarin therapy was used as a measure of anticoagulation control. Health literacy was assessed using the short form of the Test of Functional Health Literacy in Adults (S-TOFHLA). Of the 198 study participants, 51% had limited health literacy (S-TOFHLA score of 0-90) and 33% had poor anticoagulation control (TTR<50%). Participants with limited health literacy were less likely to correctly answer warfarin-related knowledge questions. Limited health literacy was significantly associated with TTR<50% (adjusted odds ratio=2.34, 95% CI [1.01, 5.46]). Findings indicate that limited health literacy is associated with poor anticoagulation control for patients on warfarin therapy. Lack of medication understanding may hinder the safe and effective use of this narrow therapeutic index drug.

Pharmacoeconomic implications of thromboprophylaxis with new oral anticoagulants after total hip or knee replacement in the USA

INTRODUCTION

Adequate thromboprophylaxis after total hip or knee replacement (THR or TKR) is essential to reduce the incidence of venous thromboembolism (VTE) and its associated complications. Although effective, traditional anticoagulants are associated with a considerable economic burden, particularly when used outside the hospital setting. This article explores whether newer oral anticoagulants can reduce costs of VTE prophylaxis and therapy.

AREAS COVERED

Cost associated with vitamin K antagonists; indirect costs associated with complicated or inconvenient anticoagulation regimens, non-adherence and associated complications; potential of the newer oral anticoagulants, including direct thrombin inhibitors and direct factor Xa inhibitors, to produce indirect cost savings after THR or TKR through a potential reduction in VTE rates and administration and monitoring costs.

EXPERT OPINION

The use of new anticoagulants for VTE prophylaxis after THR or TKR can result in direct and indirect cost savings through improved efficacy by reducing VTE rates and decreased drug administration and monitoring costs compared with traditional anticoagulants. Future research will need to focus on cost analyses driven by clinical outcomes measured on the performance of these agents in actual clinical practice.

Anticoagulant use in real time

Venous thromboembolism (VTE) encompasses deep vein thrombosis (DVT) and pulmonary embolism (PE). Each year, VTE affects about 300,000 to 600,000 people in the United States, and death is the first manifestation in one-fourth of this population.(1){Beckman, 2010 #79} Moreover, approximately 10% of the US population has genetic factors that increase their risk for developing thrombosis.(1) In addition to inherited disorders, factors that contribute to VTE include prolonged immobilization, trauma, surgery, cancer, and critically ill patients.(2) Routine assessment and prophylaxis are recommended in these groups to avoid DVT-related complications.(2) Anticoagulants are the mainstay of drugs used in DVT/PE prevention and treatment. Despite the availability of evidence-based guidelines for anticoagulant therapy, there is suboptimal implementation of DVT prophylaxis in hospitalized patients.(3) All anticoagulants are "high-alert" drugs, and judicious use is mandatory to prevent bleeding complications.(4) This review discusses treatment guidelines, monitoring, side effects, and reversal agents available for some anticoagulant drugs approved for VTE. Dissemination of the knowledge via pharmacy education programs significantly improves the adherence to VTE prophylaxis.(5) Understanding the clinical aspects of anticoagulant dispensing as presented in this review is hoped to facilitate implementation of the theoretical knowledge as well as evidence-based guidelines in order to maximize patient benefit.