Trends in utilization of warfarin and direct oral anticoagulants in older adult patients with atrial fibrillation

Efficacy and safety of rivaroxaban in preventing venous thromboembolism in postoperative patients with gynecological malignancies: protocol for a randomised controlled open-label trial (G-alfalfa trial)

INTRODUCTION

Compared with the guideline-recommended use of low-molecular weight heparin (LMWH) for 28 days to prevent venous thromboembolism (VTE) after cytoreductive surgery, oral rivaroxaban avoids the pain and inconvenience of daily injections and reduces medical expenses. The proposed randomised controlled trial (RCT) aims to compare the efficacy and safety of rivaroxaban and enoxaparin in preventing VTE in patients after surgery for gynaecological malignancies and to provide a reference for clinical medication prevention.

METHODS AND ANALYSIS

This is a single-centre, randomised, controlled, open-label and assessor-blind clinical trial. Patients undergoing surgery for gynaecological malignancies will be randomly assigned in a 1:1 ratio to an oral rivaroxaban study group and a subcutaneous injection enoxaparin control group for anticoagulant prophylaxis. The medication administration begins 12-24 hours after surgery and continues for 28 days, with a 30-day follow-up after surgery. Clinical events during the treatment and the follow-up period will be observed. The primary endpoint will be any VTE. Secondary endpoints will be any bleeding event, medication compliance rate, rivaroxaban pharmacokinetics and pharmacogenomics. The sample size required for the G-alfalfa trial is derived based on power calculations of the VTE incidence in the two intervention regimens in previous literature.

ETHICS AND DISSEMINATION

This study was approved by the Ethics Committee of Fujian Maternal and Child Health Hospital on 2 April 2024 (Approval No.:2023KY174-03). The results of the trial will be submitted for publication in a peer-reviewed journal and presented at relevant conferences.

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Registry (ChiCTR) 2300078535.

Mechanism of exacerbation of traumatic brain injury under warfarin anticoagulation in male mice

INTRODUCTION

Traumatic brain injury (TBI) is exacerbated in patients on antithrombotic medications, with warfarin leading to increased bleeding in some cases. However, the extent to which this bleeding increases lethality and its long-term effects remain unclear. This study aimed to investigate the exacerbation of TBI by warfarin treatment and comprehensively evaluate the impact of TBI on the anticoagulant effects of warfarin.

METHODS

We induced TBI in mice after pre-treatment with warfarin and analyzed TBI exacerbation based on the prothrombin time-international normalized ratio (PT-INR) value, brain hemorrhage volume, blood warfarin and 7-hydroxywarfarin levels, and cytochrome P450 2C9 (CYP2C9) protein expression. C57BL/6J mice fed with a vitamin K-deficient diet received oral warfarin (low dose, 0.35 mg/kg/24 h; high dose, 0.70 mg/kg/24 h), and focal brain damage was induced in the cerebral cortices using a brain contusion device. Warfarin-treated injured mice were compared with sham-treated mice (scalp incision alone or scalp incision + bone window formation).

RESULTS

When warfarin was administered, the PT-INR value and brain hemorrhage volume associated with cerebral contusion increased on the first day post-injury. High blood warfarin and 7-hydroxywarfarin levels were observed. However, no significant differences in CYP2C9 expression were observed between the groups.

DISCUSSION

Elevated warfarin levels post-injury can increase cerebral hemorrhage risk, possibly worsening TBI. TBI might also elevate warfarin levels, heightening its anticoagulant effects. Therefore, assessing injury severity levels and PT-INR values in patients with TBI on warfarin is crucial to anticipate delayed bleeding risks.

Pharmacokinetic and Pharmacodynamic Interactions between Food or Herbal Products and Oral Anticoagulants: Evidence Review, Practical Recommendations, and Knowledge Gaps

Interactions between food and oral anticoagulants (OACs), particularly vitamin K antagonists such as warfarin, are widely recognized and may also be clinically relevant for direct OACs. Pharmacokinetic and pharmacodynamic interactions with food or herbs can lead to anticoagulation potentiation, increased risk of bleeding, or reduced drug efficacy, all compromising patient safety. We conducted a systematic search for randomized controlled trials (RCTs) on PubMed for assessments of interactions between OACs and various ingestants. Since the RCT evidence was slim, we also reviewed prospective longitudinal studies, case series, and case reports to identify possible associations between foods and anticoagulation therapy. We referred to basic or translational studies that shared putative explanations for such interactions, but we failed to identify high-quality evidence in most cases. The limited evidence, small sample size of the studies, conflicting results, and possible heterogeneity in the contents of herbal products prevent a conclusive assessment of these interactions. Existing evidence suggests that (1) cranberry juice consumption (up to 240 mL/d and probably even more) with warfarin is safe; (2) use of green leafy vegetables with a high daily content (more than 250 µg) of vitamin K should be cautioned for patients receiving warfarin, because it may decrease warfarin efficacy. It is also advisable for patients to maintain highly constant intake of green leafy vegetables to ensure stable warfarin effectiveness; (3) ginger, even in small quantities (excluding commercial ginger-flavored beverages, which contain only negligible amounts of ginger), and mango (more than one fruit) can both potentiate warfarin effects; (4) patients taking OACs should avoid St. John's wort due to diminished anticoagulant effect; and (5) consumption of less than 240 mL of grapefruit juice daily is unlikely to interact with OACs. Future longitudinal observational cohort studies and RCTs with larger sample sizes are needed to study specific interactions between food or herbal products and OACs.

Trends in Oral Anticoagulant Use and Individual Expenditures Across the United States from 2014 to 2020

BACKGROUND

Landmark clinical trials have expended the indications for the direct oral anticoagulants (DOACs), but contemporary data on usage and expenditure patterns are lacking.

OBJECTIVE

This study aimed to assess annual trends in oral anticoagulant (OAC) utilization and expenditure across the United States (US) from 2014 to 2020.

METHODS

We utilized the Medical Expenditure Panel Survey (MEPS) to study the trends of use and expenditures of warfarin, dabigatran, rivaroxaban, apixaban, and edoxaban between 2014 and 2020 in the US. Survey respondents reported OAC use within the past year, which was verified against pharmacy records. Payment information was obtained from the respondent's pharmacy and was categorized as third-party or self/out-of-pocket. Potential indications and medical conditions of interest for OAC therapy were identified from respondent-reported medical conditions. We estimated the national number of OAC users and total expenditures across age, sex, race, ethnicity, insurance, and medical condition subgroups. Trends of OAC users' characteristics, expenditure, and number of prescriptions were evaluated using the Mann-Kendall test for trends.

RESULTS

Between 2014 and 2020, the number of warfarin users decreased from 3.8 million (70% of all OAC users) to 2.2 million (p = 0.007) [29% of all OAC users], while the number of DOAC users increased from 1.6 million (30% of all OAC users) to 5.4 million (p = 0.003) [70% of all OAC users]. The total expenditure of OACs in the US increased from $3.4 billion in 2014 to $17.8 billion in 2020 (p = 0.003), which was driven by the increase in DOAC expenditures (p = 0.003).

CONCLUSIONS

DOACs have replaced warfarin as the preferred OAC in the US. The increased costs associated with DOAC use may decline when generic formulations are approved.

Direct oral anticoagulants in skin surgery: a systematic review of their complications and recommendations for perioperative management

INTRODUCTION

Many patients undergoing cutaneous surgery are prescribed at least one anticoagulant or antiplatelet agent. With the recent emergence of direct oral anticoagulants (DOACs), there is a deficit of knowledge regarding optimal perioperative management. This review aims to evaluate the evidence and risk surrounding management of DOACs in patients undergoing skin surgeries.

METHODS

Systematic review of EMBASE, Scopus, and PubMed, with inclusion of studies that detailed perioperative management of DOACs in those undergoing skin surgery. Primary outcome measures were perioperative hemorrhagic and thromboembolic complications.

RESULTS

Seven thousand seven hundred and forty-one abstracts were identified, with 13 articles meeting inclusion criteria. Two studies investigated complication risk associated with DOAC continuation in skin surgery and found an average rate of hemorrhagic complications of 1.74%. Two studies evaluated complications associated with DOAC cessation prior to skin surgery, with a pooled thromboembolic complication rate of 0.15%. Articles comparing continuation and cessation discovered no decreased risk of bleeding with DOAC cessation prior to surgery (P = 0.93). Seven of the 13 articles compared complications in a control vs a DOAC group undergoing cutaneous procedures. Evidence was conflicting but may have suggested a small increase in bleeding risk in those on DOAC therapy.

CONCLUSION

Optimal management of anticoagulants perioperatively is difficult because of conflicting information, complicated by advent of novel agents. Risk of hemorrhagic complications with both continuation and interruption of DOAC therapy was low. Perioperative DOAC management can be guided by procedural bleeding and patient clotting risk and can often be continued in minor dermatologic procedures.

Comparative Costs to Medicare and Medicare Beneficiaries of Alternative AF Stroke Risk Reduction Strategies

Background

As healthcare costs are increasingly being shifted from payers to patients, it is important to understand the economic consequences of therapeutic strategies to both payers and patients.

Objective

To determine the relative costs to Medicare and Medicare beneficiaries (patients) of warfarin, non-vitamin K oral anticoagulants (NOACs), and left atrial appendage closure (LAAC) for stroke risk reduction in nonvalvular atrial fibrillation.

Methods

An economic model was developed to assess costs at 5 and 10 years. For warfarin and NOACs, inputs were derived from published meta-analyses; for LAAC with the Watchman device, inputs were derived from pooled 5-year PROTECT AF and PREVAIL trial results. The model captured therapy costs vs clinical event costs, including procedural complications and follow-up clinical outcomes. Costs were based on 2023 Medicare reimbursement and copayment rates.

Results

At 10 years, overall LAAC costs ($48,337) were lower than those of NOACs ($81,198) and warfarin ($52,359). Overall LAAC costs were lower than those of NOACs by year 5 and warfarin by year 9. At 5 years, patient LAAC costs were lowest at $4,764, compared to $7,146 and $6,453 for NOACs and warfarin, respectively. LAAC patient costs were lower than those of NOACs by year 3 and warfarin by year 4. Clinical events comprised 96% of overall warfarin costs vs 48% for LAAC and 40% for NOACs.

Conclusion

LAAC yielded the lowest overall and patient costs. Warfarin costs were largely driven by clinical events, which may represent an unplanned financial burden for patients. These considerations should be incorporated into shared decision-making discussions about stroke prophylaxis strategies.

Effectiveness and safety of direct oral anticoagulants versus warfarin in patients with atrial fibrillation and advanced kidney disease

BACKGROUND

The effectiveness and safety of direct oral anticoagulants (DOACs) in patients with atrial fibrillation (AF) and advanced kidney disease (AKD) has not been fully established.

OBJECTIVES

To determine the effectiveness and safety related to pooled or specific DOACs to that with warfarin in patients with AF and AKD.

METHODS

Patients with AF and AKD (estimated glomerular filtration rate < 30 mL/min) who received DOAC or warfarin from July 2011 to December 2020 were retrospectively identified in a medical center in Taiwan. Primary outcomes were hospitalized for stroke/systemic embolism and major bleeding. Secondary outcomes included any ischemia and any bleeding.

RESULTS

A total of 1,011 patients were recruited, of whom 809 (80.0%) were in the DOACs group (15.3% dabigatran, 25.4% rivaroxaban, 25.2% apixaban, and 14.1% edoxaban), and 202 (20.0%) in the warfarin group. DOACs had considerably lower risks of stroke/systemic embolism (adjusted hazard ratio [aHR] 0.29; 95% CI, 0.09-0.97) and any ischemia (aHR, 0.42; 95% CI, 0.22-0.79), but had comparable risks of major bleeding (aHR, 0.99; 95% CI, 0.34-2.92) and any bleeding (aHR, 0.74; 95% CI, 0.50-1.09) than warfarin. Apixaban was linked to considerably lower risks of any ischemia (aHR, 0.13; 95% CI, 0.04-0.48) and any bleeding (aHR, 0.53; 95% CI, 0.28-0.99) than warfarin.

CONCLUSION

Among patients with AF and AKD, DOACs were linked to a lower risk of ischemic events, and apixaban was linked to a lower risk of any ischemia and any bleeding than warfarin.

Definition of factor Xa inhibitor-related, life-threatening gastrointestinal bleeding and guidance on when to use reversal therapy: A Delphi panel

Objective

To define and contextualize life-threatening gastrointestinal (GI) bleeding in the setting of factor Xa (FXa) inhibitor therapy and to derive a consensus-based, clinically oriented approach to the administration of FXa inhibitor reversal therapy.

Methods

We convened an expert panel of clinicians representing specialties in emergency medicine, gastroenterology, vascular medicine, and trauma surgery. Consensus was reached among the clinician panelists using the Delphi technique, which consisted of 2 survey questionnaires followed by virtual, real-time consensus-building exercises.

Results

Hypovolemia and hemodynamic instability were considered the most important clinical signs of FXa inhibitor-related, life-threatening GI bleeds. Clinician panelists agreed that potentially life-threatening GI bleeding should be determined on the basis of hemodynamic instability, signs of shock, individual patient characteristics, and clinical judgment. Last, the panel agreed that all patients with life-threatening, FXa inhibitor-associated GI bleeding should be considered for FXa inhibitor reversal therapy; the decision to reverse FXa inhibition should be individualized, weighing the risks and benefits of reversal; and when reversal is elected, therapy should be administered within 1 h after initial emergency department evaluation, when possible.

Conclusions

Consensus-based definitions of life-threatening GI bleeding and approaches to FXa inhibitor reversal centered on hemodynamic instability, signs of shock, individual patient characteristics, and clinical judgment. The results from this Delphi panel may inform clinical decision-making for the treatment of patients experiencing GI bleeding associated with FXa inhibitor use in the emergency department setting.

The impact of ABCB1, CYP3A4/5 and ABCG2 gene polymorphisms on rivaroxaban trough concentrations and bleeding events in patients with non-valvular atrial fibrillation

BACKGROUND

The influence of genetic factors on the pharmacokinetics and clinical outcomes of rivaroxaban in patients with non-valvular atrial fibrillation (NVAF) is poorly understood. This study aimed to explore the effects of CYP3A4/5, ABCB1, and ABCG2 gene polymorphisms on the trough concentrations and the bleeding risk of rivaroxaban in NVAF patients.

PATIENTS AND METHODS

This study is a prospective multicenter study. The patient's blood samples were collected to detect the steady-state trough concentrations of rivaroxaban and gene polymorphisms. We visited the patients regularly at month 1, 3, 6, and 12 to record bleeding events and medications.

RESULTS

A total of 95 patients were enrolled in this study, and 9 gene loci were detected. For the dose-adjusted trough concentration ratio (Ctrough/D) of rivaroxaban, the homozygous mutant type was significantly lower than wild type at ABCB1 rs4148738 locus (TT vs. CC, P = 0.033), and the mutant type was significantly lower than the wild type at ABCB1 rs4728709 locus (AA + GA vs. GG, P = 0.008). ABCB1 (rs1045642, rs1128503), CYP3A4 (rs2242480, rs4646437), CYP3A5 (rs776746), and ABCG2 (rs2231137, rs2231142) gene polymorphisms had no significant effect on the Ctrough/D of rivaroxaban. For the bleeding events, we found that there were no significant differences among genotypes of all gene loci.

CONCLUSION

This study found for the first time that ABCB1 rs4148738 and rs4728709 gene polymorphisms had a significant impact on the Ctrough/D of rivaroxaban in NVAF patients. CYP3A4/5, ABCB1, and ABCG2 gene polymorphisms were not associated with the bleeding risk of rivaroxaban.

Periprocedural Anticoagulation

Management of patients taking anticoagulants around the time of a procedure is a common and complex clinical scenario. Providing evidence-based care requires estimation of risk for thrombosis and bleeding, knowledge of commonly used medications, multidisciplinary communication and collaboration, and patient engagement and education. This review provides a standardized, evidence-based approach to periprocedural management of anticoagulation, based on current evidence and expert clinical guidelines.

Incidence and Predictors of Switching and Dose Change of Direct Oral Anticoagulants among Elderly Patients with Nonvalvular Atrial Fibrillation: A 5-Year Analysis of a Large Administrative Database

In the last decade, novel oral anticoagulants (NOACs) have emerged as prominent therapeutic options in non-valvular atrial fibrillation (NVAF). We analysed the clinical burden and the switching rate between all available NOACs, and their dosage change over a period of 5 years in a representative population of patients with NVAF aged between 70 and 75 years. Methods and Results: This is a retrospective observational study on administrative databases, covering approximately 6.2 million health-assisted individuals by the Italian National Health System (around 11% of the entire Italian residents). Out of 4640 NVAF patients treated with NOACs and aged 70-75 years in 2017, 3772 (81.3%) patients were still in treatment with NOAC up to 2021 and among them, 3389 (73.0%) patients remained in treatment with the same NOAC during 2017-2021. In fact, 10.2% of patients switched NOAC type and 10.3% changed the dose of the same NOAC. Overall, after switching, the dabigatran and rivaroxaban groups lost, respectively, 13.5% and 2.8% of patients, while apixaban and edoxaban resulted in a relative percentage increase of 6.8% and 44.6% of patients, respectively. By a logistic regression analysis, the treatment with rivaroxaban, apixaban, and edoxaban (respect to dabigatran) was associated with a significant risk reduction of switch of 57%, 68%, and 44%, respectively. On the other hand, several features of high risk were associated with dose reduction. Conclusions. In our 5-year analysis of a large administrative database, a switching among NOACs or a change in NOAC dosages occurred in around 20% of elderly patients with NVAF. The type of NOAC was associated with a high switching rate, while several characteristics of high risk resulted as predictors of dose reduction of NOACs. Moreover, a worsening trend of clinical conditions occurred in patients maintaining the same NOAC treatment across 2017-2021.

Trends in the Use of Oral Anticoagulants for Adults With Venous Thromboembolism in the US, 2010-2020

Importance

The introduction of direct oral anticoagulants (DOACs) has transformed the treatment of venous thromboembolism (VTE). Large health care databases offer valuable insight into how oral anticoagulants (OACs) are used in clinical practice and may aid in understanding reasons for changes in therapy.

Objectives

To evaluate prescribing patterns of OACs for patients with VTE and identify clinical events that precede treatment changes.

Design, Setting, and Participants

This retrospective cohort study used data from a public (Medicare fee-for-service) and a commercial (IBM MarketScan) health insurance database on 298 609 patients initiating OACs within 90 days of index VTE hospitalization from January 1, 2009, to December 31, 2020. Statistical analysis was conducted from April to August 2022.

Exposures

Warfarin and the DOACs rivaroxaban, apixaban, dabigatran, and edoxaban.

Main Outcomes and Measures

Characteristics of patients initiating different OACs, along with trends over time of patients initiating OACs, were compared. Time receiving continuous anticoagulant therapy, patterns of anticoagulant discontinuation (treatment gap of ≥30 days), and treatment switches were assessed. Clinical events in the 30 days preceding treatment modifications were identified.

Results

A total of 203 378 individuals with Medicare (mean [SD] age, 76.9 [7.6] years; 122 554 women [60.3%]) and 95 231 with commercial insurance (mean [SD] age, 57.6 [15.8] years; 47 139 women [49.5%]) were included (N = 298 609). Warfarin was the most frequent OAC prescribed (163 044 [54.6%]), followed by rivaroxaban (66 882 [22.3%]) and apixaban (65 997 [22.1%]). The proportion of patients initiating DOACs increased from 0% in 2010 to 86.8% (22 420 of 25 817) in 2019 for patients with Medicare and 92.1% (4012 of 4357) in 2020 for commercially insured patients. Patients with chronic kidney disease were more likely to initiate warfarin (35 561 [11.9%]) or apixaban (16 294 [5.5%]) than rivaroxaban (10 136 [3.4%]), and those with a history of bleeding were more likely to initiate apixaban (5424 [1.8%]) than rivaroxaban (3007 [1.0%]). Overall, patients received persistent OAC treatment for approximately 6 months (Medicare: median, 175 days [IQR, 76-327 days]; commercial insurance: median, 168 days [IQR, 83-279 days]). A total of 33 011 patients (11.1%) switched anticoagulant therapy within a year. Switching to another anticoagulant was preceded most frequently by codes for a VTE diagnostic procedure (27.2% of all switchers [8983 of 33 011]).

Conclusions and Relevance

This cohort study using data from 2 US health insurance databases suggests that most patients with VTE continued oral anticoagulant treatment for approximately 6 months. Clinical reasons for modifying anticoagulant therapy were identified in one-third of patients. Identifying reasons for treatment modification is crucial for generating valid evidence on drug safety and effectiveness.

Trend of anticoagulant therapy in elderly patients with atrial fibrillation considering risks of cerebral infarction and bleeding

The introduction of direct oral anticoagulants (DOACs) has greatly changed the use of anticoagulant therapy in patients with non-valvular atrial fibrillation (Af). Therefore, this study aimed to examine changes in the proportions of oral anticoagulant prescriptions in patients with non-valvular Af aged ≥ 65 years, taking into consideration the risk of cerebral infarction and bleeding. Anticoagulant prescriptions in outpatients aged ≥ 65 years with Af were temporally analyzed using the nationwide claims database in Japan. Trends in anticoagulant prescriptions were examined according to cerebral infarction and bleeding risk. The proportion of anticoagulant prescriptions for 12,076 Af patients increased from 41% in 2011 to 56% in 2015. An increase in DOAC prescriptions was accompanied by an increase in the proportion of anticoagulant prescriptions in each group according to the CHA2DS2-VASc and HAS-BLED scores. The proportion of anticoagulant prescriptions for patients with a high risk of developing cerebral infarction and bleeding showed a marked increase. Trends in anticoagulant prescriptions in Af patient with a CHA₂DS₂-VASc score ≥ 2 and HAS-BLED scores ≥ 3 showed a marked increase in DOAC prescriptions. The widespread use of DOACs greatly changes the profile the prescription of anticoagulant therapy in patients with Af.

Evidence-based Management of Major Bleeding in Patients Receiving Direct Oral Anticoagulants: An Updated Narrative Review on the Role of Specific Reversal Agents

The indications of direct oral anticoagulants (DOACs) have expanded over the past 15 years. DOACs are effective and safe oral anticoagulants associated with lower bleeding risks and mortality than vitamin K antagonists. However, DOAC users are prone to a considerable bleeding risk, which can occur at critical sites or lead to severe life-threatening conditions. Recent statistics indicated that major bleeding occurs in up to 6.62 DOAC users per 100 treatment years. With the increased use of DOACs in clinical practice, DOAC-associated major bleeding is expected to be encountered more frequently in the emergency department. The current international guidelines recommend specific reversal agents for the management of DOAC users with severe bleeding to reverse the anticoagulant effect and restore normal hemostasis. An individualized assessment was incorporated in specific clinical situations to guide the decision pathway of major bleeding management. However, specific reversal agents are unavailable or have limited availability in many countries, which is expected to negatively impact the clinical outcomes of DOAC-associated major bleeding. Limited real-world evidence is available from these countries regarding the clinical outcomes of patients with DOAC-associated major bleeding. This narrative review provided an updated assessment of the evidence-based approaches for the management of major bleeding in DOAC users. We also explored the clinical outcomes of patients with major bleeding from clinical settings where specific reversal agents are unavailable.

Trough Concentration Deficiency of Rivaroxaban in Patients With Nonvalvular Atrial Fibrillation Leading to Thromboembolism Events

ABSTRACT

This retrospective study investigated factors influencing the steady-state trough concentrations (C trough ) of rivaroxaban in patients with nonvalvular atrial fibrillation (NVAF). We retrieved data from patients with NAVF who first started rivaroxaban anticoagulation at the Fujian Provincial Hospital from October 2017 to October 2020 through the electronic medical record system. Patients were followed for 1 year after the first dose of rivaroxaban, and the primary efficacy and safety end points were recorded. All follow-up visits were completed by October 2021. A C trough of <12 ng/mL was defined as C trough deficiency. Factors that influenced rivaroxaban C trough deficiency were investigated using multivariate binary logistic regression analysis. Kaplan-Meier survival curve analysis was used to determine differences between C trough deficiency and event-free survival. A total of 167 patients with NVAF were enrolled in the study, including 113 men and 54 women, with an average (± SD) age of 70.40 ± 12.46 years. High albumin levels were an independent protective factor against C trough deficiency (odds ratio, 0.932; P = 0.031). C trough deficiency was associated with the probability of freedom from thrombotic events ( P = 0.004); however, there were no significant differences in the probability of freedom from bleeding events ( P > 0.05). In conclusion, among the variables studied, a low albumin level was the main contributor to C trough deficiency. Rivaroxaban C trough deficiency also increased thrombotic events, but this was not associated with hemorrhagic events in Chinese patients with NVAF.

Prescribing Trends of Oral Anticoagulants from 2010 to 2020 in Shanghai, China: A Retrospective Study

Aim

Non-vitamin K antagonist oral anticoagulants (NOACs) were developed as an alternative to warfarin to prevent thromboembolism in patients with atrial fibrillation (AF), prosthetic heart valves, venous thromboembolism (VTE), or other thrombotic disorders. The aim of this study is to explore the trends in prescribing OACs, including warfarin and NOACs, in Shanghai, China.

Methods

Prescription data of OACs were retrospectively collected from Rx Analysis System from 2010 to 2020 in Shanghai, China. Comparisons were made on the trends of each OACs according to different indications, age groups, and hospital grades. The costs and the contribution of individual OACs were also explored.

Results

Growing trends in overall prescriptions for OACs were observed. The prescriptions of NOACs were significantly increased since 2016, while the prescriptions of warfarin kept decreasing since 2017. A highly statistically significant increase in prescriptions of Rivaroxaban was observed from 2016 to 2020 (P < .001). Despite the price reduction of rivaroxaban in 2018, the total cost of rivaroxaban continued to rise (P < .001). Rivaroxaban emerged as a preferred NOAC in both indications of AF and VTE, and accounted for more than three-quarters of the total costs for OACs since 2019. Compared with rivaroxaban, the prescription numbers of dabigatran and apixaban were much smaller, and the growth of prescriptions were much slower. Differences in prescribing patterns in different indications, age groups, and grades of hospitals were also founded.

Conclusion

There has been a rapid increase in the use of OAC over the last 11 years in Shanghai, China. NOACs have been adopted rapidly, and have been gradually replacing warfarin. Warfarin remains the top choice for certain patients with valvular heart disease. Future studies are warranted considering changes in the OAC use in a larger scale, as well as the rationality and its influence factors on OAC use.

The Influence of ABCB1 (rs1045642 and rs4148738) Gene Polymorphisms on Rivaroxaban Pharmacokinetics in Patients Aged 80 Years and Older with Nonvalvular Atrial Fibrillation

INTRODUCTION

ABCB1 gene polymorphisms are associated with rivaroxaban distribution changes and adverse reactions but the data are controversial.

AIM

To evaluate the influence of ABCB1 (rs1045642 and rs4148738) gene polymorphisms on rivaroxaban pharmacokinetics in patients aged 80 years and older with nonvalvular atrial fibrillation (NAF).

METHODS

128 patients aged 80 years and older (median [Me] age 87.5 [83.0-90.0] years) with NAF were included. We performed ABCB1 (rs1045642 and rs4148738) genotyping, measured the trough steady-state plasma concentration (C_min,ss) of rivaroxaban and prothrombin time (PT) and analyzed prior medical records for clinically relevant non-major bleeding (CRNMB).

RESULTS

CC genotype carriers had no differences in C_min,ss (p > 0.05) compared with the CT and TT rs1045642 and rs4148738 genotypes carriers. CC genotype carriers had no differences in PT (p > 0.05) compared with the CT rs1045642 and rs4148738 and TT rs4148738 genotypes carriers. In the TT genotype PT levels were higher than in the CC rs1045642 genotype: Me 14.2 [13.0-16.1] sec vs 13.3 [12.4-14.5] sec (p = 0.049). Incidence of CRNMB was higher in patients with the TT genotype compared with the CC rs1045642 (29.3% vs 4.5%, p = 0.021) and rs4148738 (39.3% vs 8.1%, p = 0.008) and the CT genotype rs4148738 (39.3% vs 14.3%, p = 0.002).

CONCLUSION

ABCB1 (rs1045642 and rs4148738) polymorphisms didn't influence rivaroxaban pharmacokinetics in patients aged 80 years and older with NAF. TT carriers developed CRNMB more frequently compared with the CC rs1045642 and the CC and CT rs4148738 genotypes. The haplotype TT-TT haplotype was associated with a higher frequency of CRNMB.

Population Pharmacokinetics of Rivaroxaban in Chinese Patients with Non-Valvular Atrial Fibrillation: A Prospective Multicenter Study

BACKGROUND AND OBJECTIVE

Rivaroxaban is a novel oral anticoagulant widely used for thromboprophylaxis in patients with non-valvular atrial fibrillation (NVAF). The present study aimed to develop a population pharmacokinetic (PPK) model for rivaroxaban in Chinese patients with NVAF.

METHODS

We performed a prospective multicenter study. The plasma concentration of rivaroxaban was directly detected by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and indirectly by rivaroxaban-calibrated chromogenic anti-Xa assay (STA^®). Gene polymorphisms were detected by MassARRAY single nucleotide polymorphism genotyping technology. Nonlinear mixed-effects modeling was used to develop the PPK model for rivaroxaban in patients with NVAF, and we simulated the steady-state rivaroxaban exposures under different dosing strategies in different covariate levels.

RESULTS

A total of 150 patients from five centers were recruited, including 263 plasma concentrations detected by HPLC-MS/MS, 2626 gene polymorphisms, and 131 plasma concentrations detected by anti-Xa assay. In our study, an oral one-compartment model was used to describe the pharmacokinetics of rivaroxaban in patients with NVAF. In the final model, the estimated apparent clearance (CL/F) and volume of distribution (V/F) were 5.79 L/h (relative standard error [RSE] 4.4%) and 51.5 L (RSE 5.0%), respectively. Covariates in the final model included creatinine clearance, total bilirubin, rs4728709, and body weight. The simulation results showed that in the 15 mg once-daily dosing regimen, in most instances the maximum plasma concentration at steady state (C_max,ss) and trough plasma concentration at steady state (C_min,ss) were in the target range for different covariate levels. When patients were administered rivaroxaban 15 or 20 mg once daily, the C_max,ss and C_min,ss in the different bodyweight levels were also in the target range. For patients with the ABCB1 rs4728709 mutation, the C_min,ss in the 10, 15, and 20 mg once-daily dosing regimens were lower than the target range. The anti-Xa assay was highly linearly correlated with the HPLC-MS/MS method [y = 1.014x - 2.4648 (R² = 0.97)].

CONCLUSIONS

Our study was the first multicenter PPK model for rivaroxaban in Chinese patients with NVAF (Alfalfa-RIVAAF-PPK). The study found that 15 mg once daily may be suitable as the principal rivaroxaban dose for Chinese patients with NVAF. For patients with the rs4728709 mutation, it may be necessary to examine insufficient anticoagulation. We found that the rivaroxaban-calibrated chromogenic anti-Xa assay and HPLC-MS/MS method were highly linearly correlated. Prospective studies with larger sample sizes and real-world studies are needed for further verification.

Prevalence of Frailty and Associations with Oral Anticoagulant Prescribing in Atrial Fibrillation

BACKGROUND

Frailty is often cited as a factor influencing oral anticoagulation (OAC) prescription in patients with non-valvular atrial fibrillation (NVAF). We sought to determine the prevalence of frailty and its association with OAC prescription in older veterans with NVAF.

METHODS

We used ICD-9 codes in Veterans Affairs (VA) records and Medicare claims data to identify patients with NVAF and CHA2DS2VASC ≥2 receiving care between February 2010 and September 2015. We examined rates of OAC prescription, further stratified by direct oral anticoagulant (DOAC) or vitamin K antagonist (VKA). Participants were characterized into 3 categories: non-frail, pre-frail, and frail based on a validated 30-item EHR-derived frailty index. We examined relations between frailty and OAC receipt; and frailty and type of OAC prescribed in regression models adjusted for factors related to OAC prescription.

RESULTS

Of 308,664 veterans with NVAF and a CHA2DS2VASC score ≥2, 121,839 (39%) were prescribed OAC (73% VKA). The mean age was 77.7 (9.6) years; CHA2DS2VASC and ATRIA scores were 4.6 (1.6) and 5.0 (2.9) respectively. Approximately a third (38%) were frail, another third (32%) were pre-frail, and the remainder were not frail. Veterans prescribed OAC were younger, had higher bleeding risk, and were less likely to be frail than participants not receiving OAC (all p's<0.001). After adjustment for factors associated with OAC use, pre-frail (OR: 0.89, 95% CI: 0.87-0.91) and frail (OR: 0.66, 95% CI: 0.64-0.68) veterans were significantly less likely to be prescribed OAC than non-frail veterans. Of those prescribed OAC, pre-frail (OR:1.27, 95% CI: 1.22-1.31) and frail (OR: 1.75, 95% CI: 1.67-1.83) veterans were significantly more likely than non-frail veterans to be prescribed a DOAC than a VKA.

CONCLUSIONS

There are high rates of frailty among older veterans with NVAF. Frailty using an EHR-derived index is associated with decreased OAC prescription.

Impact of Drug Interactions on Major Bleed Rates in Patients Taking Direct Oral Anticoagulants

Background: While direct oral anticoagulants (DOACs) have less stringent monitoring, favorable pharmacokinetics, and fewer drug interactions compared to warfarin, there is still a potential for drug–drug interactions. There is limited evidence showing total impact of DOAC drug interactions on major bleeding events. Methods: This was an IRB-approved retrospective, case control, single center study. Patients were included if they had received a DOAC from January 2012 to September 2019 and were identified for major bleeding events and matched to a control group. The primary objective was to compare the presence of major drug interactions between patients on DOACs who did and did not have a major bleeding event. The secondary objectives were to compare the impact of specific interacting drug classes and their additive effects on major bleeding events. Results: There were 122 patients included in the study. While the number of patients on at least one interacting medication within duration of DOAC use was numerically higher in the bleed group (85% vs 72%), this was not significant (P = .077). There were significantly more patients on at least three interacting medications within the last 3 months of the study period in the bleed group (n = 9 vs 1), with significantly higher use of aspirin (n = 38 vs 17) and rate control agents (n = 24 vs 11). Conclusion: There may be a cumulative effect on risk of bleeding if patients are on three or more interacting medications concomitantly with a DOAC. This risk of bleeding may be higher with aspirin and rate control agents.

Management of Atrial Fibrillation in Patients 75 Years and Older: JACC State-of-the-Art Review

The prevalence of atrial fibrillation (AF) is increasing as the population ages. AF treatment-related complications also increase markedly in older adults (defined as ≥75 years of age for this review). The older AF population has a high risk of stroke, bleeding, and death. Syncope and fall-related injuries are the most common reasons for nonprescription of oral anticoagulation (OAC), and are more common in older adults when OACs are used with antiarrhythmic drugs. Digoxin may be useful for rate control, but associations with increased mortality limit its use. Beyond rate and rhythm control considerations, stroke prophylaxis is critical to AF management, and the benefits of direct OACs, compared with warfarin, extend to older adults. Invasive procedures such as AF catheter ablation, pacemaker implantation/atrioventricular junction ablation, and left atrial appendage occlusion may be useful in appropriately selected cases. However, older adults have generally been under-represented in clinical trials.

Time Trends and Treatment Pathways in Prescribing Individual Oral Anticoagulants in Patients with Nonvalvular Atrial Fibrillation: An Observational Study of More than Three Million Patients from Europe and the United States

BACKGROUND

Data directly comparing trends in the use of different oral anticoagulants (OACs) among patients with atrial fibrillation (AF) from different countries are limited. We addressed this using a large-scale network cohort study in the United States (US), Belgium, France, Germany, and the United Kingdom (UK).

METHODS

We used nine databases (claims or electronic health records) that had been converted into the Observational Medical Outcomes Partnership Common Data Model with analysis performed using open-source analytical tools. We identified adults with AF and a first OAC prescription, either vitamin K antagonist (VKA) or direct oral anticoagulant (DOAC), from 2010 to 2017. We described time trends in use, continuation, and switching.

RESULTS

In 2010, 87.5%-99.8% of patients started on a VKA. By 2017, the majority started on a DOAC: 87.0% (US), 88.3% (Belgium), 93.1% (France), 88.4% (Germany), and 86.1%-86.7% (UK). In the UK, DOACs became the most common starting OAC in 2015, 2-3 years later than elsewhere. Apixaban was the most common starting OAC by 2017, 50.2%-57.8% (US), 31.4% (Belgium), 45.9% (France), 39.5% (Germany), and 49.8%-50.5% (UK), followed by rivaroxaban, 24.8%-32.5% (US), 25.7% (Belgium), 38.4% (France), 24.9% (Germany), and 30.2%-31.2% (UK). Long-term treatment was less common in the US than in Europe, especially the UK. A minority of patients switched from their index OAC in the short and long term.

CONCLUSIONS

From 2010 to 2017, VKA use had significantly declined and DOAC use had significantly increased in the US and Europe. Apixaban was the most prescribed OAC in 2017, followed by rivaroxaban.

Meta-analysis comparing inappropriately low dose versus standard dose of direct oral anticoagulants in patients with atrial fibrillation

BACKGROUND

The appropriateness of direct oral anticoagulant (DOAC) dosing has been the issue in the real-world setting, and inappropriately lower DOAC dose may not be as effective or safe as the standard dose in patients with atrial fibrillation (AF). Multiple real-world studies compared the inappropriately lower DOAC dose versus the standard dose, but their main findings were contradictory.

METHODS

A meta-analysis was performed to compare the efficacy and safety of the inappropriately lower DOAC dose with the standard DOAC dose in patients with AF. Database searches through May 30, 2021, were performed using Medline and Google Scholar. The primary efficacy outcome was stroke or systemic embolism, and the primary safety outcome was major bleeding. The secondary outcome was all-cause mortality.

RESULTS

A total of 16 studies were included in this meta-analysis. It revealed that the inappropriately lower DOAC dose was significantly associated with a higher event rate of stroke or systemic embolism compared with the DOAC standard dose (odds ratio 1.21 [95% CI 1.02-1.43], P = 0.03, I² = 66%). There was no significant difference in the major bleeding event rate between these groups (1.03, [0.92-1.15], P = 0.62; I² = 27%).

CONCLUSION

The inappropriately lower DOAC dose should be avoided to optimize DOAC effectiveness in patients with AF.

Underutilization of Peptic Ulcer Disease Prophylaxis Among Elderly Users of Antiplatelets and Anticoagulants

INTRODUCTION

Peptic ulcer disease (PUD) develops in approximately 25% of chronic users of non-steroidal anti-inflammatory drugs (NSAIDs). The incidence of uncomplicated PUD has been declining over the past 3 decades unlike that of complicated PUD in the elderly. An expert consensus document published jointly in 2008 by the American College of Gastroenterology (ACG), the American College of Cardiology Foundation (ACCF), and the American Heart Association (AHA) provided recommendations on prevention of PUD among users of antiplatelets and anticoagulants. This work aimed to evaluate physicians' compliance with these guidelines in a tertiary academic setting.

METHODS

We examined our medical record database for the 9 month period extending from April 2018 until December 2018. Using this database, we identified elderly patients (> 64 years old) who were chronic (> 3 months) users of low dose aspirin (81 mg once daily) and had an indication for PUD prophylaxis as per the ACG-ACCF-AHA guideline document. We performed a retrospective chart review of patients included in this study. Descriptive statistics were compared using χ² and independent sample t tests.

RESULTS

A total of 852 patients were included in this study. The mean age was 75 years old, and 43% of patients were females. In addition to aspirin, patients were prescribed P2Y12 inhibitors (45.5%), direct oral anticoagulants (DOACs) (23%), warfarin (12%), steroids (9%) or enoxaparin (1%). Users of DOACs were most commonly prescribed apixaban (16%), followed by rivaroxaban (6%) and dabigatran (1%). Overall, only 40% of patients with an indication for PUD prophylaxis received a proton pump inhibitor.

CONCLUSION

PUD prophylaxis may be underutilized in elderly patients. This finding, along with increasing rates of NSAID use and an aging population, may help explain the increased incidence of complicated PUD in the elderly. Efforts are needed to raise physician awareness of PUD prophylaxis guidelines.

Barriers and facilitators for optimizing oral anticoagulant management: Perspectives of patients, caregivers, and providers

BACKGROUND

Oral anticoagulants (OACs) are very commonly prescribed for prevention of serious vascular events, but are also associated with serious medication-related bleeding. Mitigation of harm is believed to require high-quality OAC management. This study aimed to identify barriers and facilitators for optimal OAC management from the perspective of patients, caregivers and healthcare providers.

METHODS

Using a qualitative descriptive study design, we conducted five focus groups, three with patients and caregivers and two with health care providers, in two health regions in Southwestern Ontario. An expert facilitator led the discussions using a semi-structured interview guide. Each session was digitally recorded, transcribed verbatim and anonymized. Transcripts were analyzed in duplicate using conventional content analysis.

RESULTS

Forty-two (19 patients, 7 caregivers, and 16 providers including physicians, nurses and pharmacists) participated. More than half of the patients received OAC for the treatment of venous thromboembolism (57.9%) and the majority (94.7%) were on chronic therapy (defined as >3 years). Data analysis organized codes describing barriers and facilitators into 4 main themes-medication-related, patient-related, provider-related, and system-related. Barriers highlighted were problems with medication access due to cost, patient difficulties with adherence, knowledge and adjusting their lifestyles to OAC therapy, provider expertise, time for adequate communication amongst providers and their patients, and health care system inadequacies in supporting communications and monitoring. Facilitators identified generally addressed these barriers.

CONCLUSIONS

Many barriers to optimal OAC management exist even in the era of DOACs, many of which are amenable to facilitators of improved care coordination, patient education, and adherence monitoring.

Switching of oral anticoagulants in patients with non-valvular atrial fibrillation: A narrative review

Approval of direct-acting oral anticoagulants (DOACs) for stroke prevention in atrial fibrillation (AF) was an important milestone, providing a wider range of treatment options and creating the possibility for drug switching after initiation. In addition to improved utilisation of oral anticoagulants (OACs) for stroke prevention, reports of switching among OACs are growing in the literature; switching may influence clinical outcomes, healthcare costs and patient satisfaction. This review aimed to summarise the current literature on the pattern of OAC switching in patients with AF, including reasons for switching and clinical consequences following switching. A literature search was conducted in PubMed, Scopus, and Embase on Jun 27, 2020. We included 39 articles published after 2013, following the introduction of apixaban. The review found that switching among OACs was common in clinical practice, significantly varying with the type of OAC. Studies reporting the reason for switching and clinical outcomes were comparatively limited. The decision to switch was often related to safety issues (usually bleeding), poor anticoagulation control and ease-of-use. Patient characteristics, clinical conditions and drug interactions were found to be associated with switching from OACs. Findings regarding bleeding outcomes following switching were inconsistent, possibly confounded by the rationale for switching and the switching protocol. Noting the limited number of studies included and their relatively short follow-up periods, switching did not have a significant impact on the risk of stroke and other thrombotic outcomes. Further prospective studies are needed to understand better potential rationales for switching and the clinical outcomes.

Changes in anticoagulant prescription patterns over time for patients with atrial fibrillation around the world

BACKGROUND

Prescribing patterns for stroke prevention in atrial fibrillation (AF) patients evolved with approval of non-Vitamin K antagonist oral anticoagulants (NOACs) over time.

OBJECTIVES

To assess changes in anticoagulant prescription patterns in various geographical regions upon first approval of a NOAC and to analyze the evolution of oral anticoagulants (OACs) use over time in relation to CHA2DS2-VASc and HAS-BLED risk profiles.

METHODS

Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF) Phases II and III reported data on antithrombotic therapy for patients with newly diagnosed AF and ≥1 stroke risk factor. We focused on sites enrolling patients in both phases and reported treatment patterns for the first 4 years after initial NOAC approval.

RESULTS

From GLORIA-AF Phases II and III, 27 432 patients were eligible for this analysis. When contrasting the first year with the fourth year of enrolment, the proportion of NOAC prescriptions increased in Asia from 29.2% to 60.8%, in Europe from 53.4% to 75.8%, in North America from 49.0% to 73.9% and in Latin America from 55.7% to 71.1%. The proportion of Vitamin K antagonists (VKAs) use decreased across all regions over time, in Asia from 26.0% to 9.8%, in Europe from 35.5% to 16.8%, in North America from 28.9% to 12.1%, and in Latin America from 32.4% to 17.8%. In the multivariable analysis, factors associated with NOAC prescription were as follows: enrolment year, type of site, region, stroke and bleeding risk scores, and type and categorization of AF.

CONCLUSIONS

During 4 years after the approval of the first NOAC, NOAC use increased, while VKA use decreased, across all regions.

Effectiveness and Safety of Direct Oral Anticoagulants Versus Warfarin in Patients With Valvular Atrial Fibrillation : A Population-Based Cohort Study

BACKGROUND

Direct oral anticoagulants (DOACs) are increasingly used in place of warfarin, but evidence about their effectiveness and safety in patients with valvular atrial fibrillation (AF) remains limited.

OBJECTIVE

To assess the effectiveness and safety of DOACs compared with warfarin in patients with valvular AF.

DESIGN

New-user retrospective propensity score-matched cohort study.

SETTING

U.S.-based commercial health care database from 1 January 2010 to 30 June 2019.

PARTICIPANTS

Adults with valvular AF who were newly prescribed DOACs or warfarin.

MEASUREMENTS

The primary effectiveness outcome was a composite of ischemic stroke or systemic embolism. The primary safety outcome was a composite of intracranial or gastrointestinal bleeding.

RESULTS

Among a total of 56 336 patients with valvular AF matched on propensity score, use of DOACs (vs. warfarin) was associated with lower risk for ischemic stroke or systemic embolism (hazard ratio [HR], 0.64 [95% CI, 0.59 to 0.70]) and major bleeding events (HR, 0.67 [CI, 0.63 to 0.72]). The results for the effectiveness and safety outcomes remained consistent for apixaban (HRs, 0.54 [CI, 0.47 to 0.61] and 0.52 [CI, 0.47 to 0.57], respectively) and rivaroxaban (HRs, 0.74 [CI, 0.64 to 0.86] and 0.87 [CI, 0.79 to 0.96], respectively); with dabigatran, results were consistent for the major bleeding outcome (HR, 0.81 [CI, 0.68 to 0.97]) but not for effectiveness (HR, 1.03 [CI, 0.81 to 1.31]).

LIMITATION

Relatively short follow-up; inability to ascertain disease severity.

CONCLUSION

In this comparative effectiveness study using practice-based claims data, patients with valvular AF who were new users of DOACs had lower risks for ischemic stroke or systemic embolism and major bleeding than new users of warfarin. These data may be used to guide risk-benefit discussions regarding anticoagulant choices for patients with valvular AF.

PRIMARY FUNDING SOURCE

None.

Drug-drug Interactions with Warfarin: A Systematic Review and Meta-analysis

AIM

The objective of this paper is to systematically review the literature on drug-drug interactions with warfarin, with a focus on patient-important clinical outcomes.

METHODS

MEDLINE, EMBASE, and the International Pharmaceutical Abstract (IPA) databases were searched from January 2004 to August 2019. We included studies describing drug-drug interactions between warfarin and other drugs. Screening and data extraction were conducted independently and in duplicate. We synthesized pooled odds ratios (OR) with 95% confidence intervals (CIs), comparing warfarin plus another medication to warfarin alone. We assessed the risk of bias at the study level and evaluated the overall certainty of evidence using GRADE.

RESULTS

Of 42,013 citations identified, a total of 72 studies reporting on 3,735,775 patients were considered eligible, including 11 randomized clinical trials and 61 observational studies. Increased risk of clinically relevant bleeding when added to warfarin therapy was observed for antiplatelet (AP) regimens (OR=1.74; 95% CI 1.56, 1.94), many antimicrobials (OR=1.63; 95% CI 1.45, 1.83), NSAIDs including COX-2 NSAIDs (OR=1.83; 95% CI 1.29, 2.59), SSRIs (OR=1.62; 95% CI 1.42, 1.85), mirtazapine (OR=1.75; 95% CI 1.30, 2.36), loop diuretics (OR=1.92; 95% CI 1.29, 2.86), and others. We found a protective effect of proton pump inhibitors (PPIs) against warfarin-related gastrointestinal (GI) bleedings (OR=0.69; 95% CI 0.64, 0.73). No significant effect on thromboembolic events or mortality of any drug group used with warfarin was found, including single or dual AP regimens.

CONCLUSIONS

This review found low to moderate certainty evidence supporting the interaction between warfarin and a small group of medications, which result in increased bleeding risk. PPIs are associated with reduced hospitalization for upper GI bleeding for patients taking warfarin. Further studies are required to better understand drug-drug interactions leading to thromboembolic outcomes or death.

Geographic Variation in Anticoagulant Use and Resident, Nursing Home, and County Characteristics Associated With Treatment Among US Nursing Home Residents

OBJECTIVES

To quantify geographic variation in anticoagulant use and explore what resident, nursing home, and county characteristics were associated with anticoagulant use in a clinically complex population.

DESIGN

A repeated cross-sectional design was used to estimate current oral anticoagulant use on December 31, 2014, 2015, and 2016.

SETTING AND PARTICIPANTS

Secondary data for United States nursing home residents during the period 2014-2016 were drawn from the Minimum Data Set 3.0 and Medicare Parts A and D. Nursing home residents (≥65 years) with a diagnosis of atrial fibrillation and ≥6 months of Medicare fee-for-service enrollment were eligible for inclusion. Residents in a coma or on hospice were excluded.

METHODS

Multilevel logistic models evaluated the extent to which variation in anticoagulant use between counties could be explained by resident, nursing home, and county characteristics and state of residence. Proportional changes in cluster variation (PCVs), intraclass correlation coefficients (ICCs), and adjusted odds ratios (aORs) were estimated.

RESULTS

Among 86,736 nursing home residents from 11,860 nursing homes and 1694 counties, 45% used oral anticoagulants. The odds of oral anticoagulant use were 18% higher in 2016 than 2014 (aOR: 1.18; 95% confidence interval: 1.14-1.22). Most states had counties in the highest (51.3-58.9%) and lowest (31.1%-41.4%) deciles of anticoagulant use. Compared with the null model, adjustment for resident characteristics explained one-third of the variation between counties (PCV: 34.8%). The full model explained 65.5% of between-county variation. Within-county correlation was a small proportion (ICC < 2.2%) of total variation.

CONCLUSIONS AND IMPLICATIONS

In this older adult population at high risk for ischemic stroke, less than half of the residents received treatment with anticoagulants. Variation in treatment across counties was partially attributable to the characteristics of residents, nursing homes, and counties. Comparative evidence and refinement of predictive algorithms specific to the nursing home setting may be warranted.

Healthcare resource utilization following ECG sensor patch screening for atrial fibrillation

BACKGROUND

Screening for asymptomatic, undiagnosed atrial fibrillation (AF) has the potential to allow earlier treatment, possibly resulting in prevention of strokes, but also to increase medical resource utilization.

OBJECTIVE

To compare healthcare utilization rates during the year following initiation of screening among participants screened for AF by electrocardiogram (ECG) sensor patch compared with a matched observational control group.

METHODS

A total of 1718 participants recruited from a health care plan based on age and comorbidities who were screened with an ECG patch (actively monitored group) as part of a prospective, pragmatic research trial were matched by age, sex, and CHA2DS2-VASc score with 3371 members from the same health plan (observational control group). Healthcare utilization, including visits, prescriptions, procedures, and diagnoses, during the 1 year following screening was compared between the groups using health plan claims data.

RESULTS

Overall, the actively monitored group had significantly higher rates of cardiology visits (adjusted incidence rate ratio [aIRR] [95% confidence interval (CI)]: 1.43 [1.27, 1.60]), no difference in primary care provider visits (aIRR [95% CI]: 1.0 [0.95, 1.05]), but lower rates of emergency department (ED) visits and hospitalizations (aIRR [95% CI]: 0.80 [0.69, 0.92]) compared with controls. Among those with newly diagnosed AF, the reduction in ED visits and hospitalizations was even greater (aIRR [95% CI]: 0.27 [0.17, 0.43]).

CONCLUSION

AF screening in an asymptomatic, moderate-risk population with an ECG patch was associated with an increase in cardiology outpatient visits but also significantly lower rates of ED visits and hospitalizations over the 1 year following screening.

New Pharmacogenetic Markers to Predict the Risk of Bleeding During Taking of Direct Oral Anticoagulants

Aim. To search for new pharmacogenetic biomarkers of bleeding risk in patients taking rivaroxaban and dabigatran for different indications: atrial fibrillation, endoprosthesis of large joints of lower limbs.

Material and methods. The study enrolled 29 patients (17 patients received dabigatran and 12 –rivaroxaban), who had hemorrhagic complications during taking direct oral anticoagulants. To find new pharmacogenetic biomarkers of bleeding risk, a next generation sequencing (NGS) was performed for selected candidate genes.

Results. Among the patients with bleeding who received dabigatran, 13 variants of the nucleotide sequence showed statistically significant deviation from the population values: 11 in the CES1 gene and 2 in the ABCB1 gene. Among the patients with bleeding who received rivaroxaban, 7 variants of nucleotide sequence showed significant deviation: 4 in the ABCG2 gene, 2 in the CYP3A4 gene, and 1 in the ABCB1 gene.

Conclusion. The identified in this study polymorphisms of candidate genes ABCB1, ABCG2, CES1, CYP3A4 were associated with the risk of bleeding in patients taking rivaroxaban and dabigatran. It makes an important contribution to the pharmacogenetics of direct oral anticoagulants and require additional assessment of clinical significance in further studies.

Use of non-vitamin K antagonist oral anticoagulants in Colombia: A descriptive study using a national administrative healthcare database

PURPOSE

We aimed to describe time-trends in the use of NOACs among a group of ambulatory patients with nonvalvular atrial fibrillation (NVAF) in Colombia and to describe treatment patterns and user characteristics.

METHODS

Using the Audifarma S.A administrative healthcare database in Colombia, we identified 10 528 patients with NVAF aged at least 18 years between July 2009 and June 2017 with a first prescription (index date) for apixaban, dabigatran or rivaroxaban (index NOAC) and followed them for at least year (max, 8.0 years, mean 2.2 years). We described patient characteristics, NOAC use over time, and the dose of the first NOAC prescription.

RESULTS

A total of 2153 (20.5%) patients started on apixaban, 3089 (29.3%) on dabigatran and 5286 (50.2%) on rivaroxaban. The incidence of new users of apixaban and rivaroxaban increased over study years while for dabigatran it decreased. Mean age at the index date was: 78.5 years (apixaban), 76.5 years (dabigatran), 76.0 years (rivaroxaban). The percentage of patients started NOAC therapy on the standard dose was: apixaban 38.0%, dabigatran 30.9%, rivaroxaban 56.9%. The percentage still prescribed their index NOAC at 6 months was apixaban 44.6%, dabigatran 51.4%, rivaroxaban 52.7%. Hypertension was the most common comorbidity (>80% in each NOAC cohort).

CONCLUSION

During the last decade, the incidence of NOAC use in patients with NVAF affiliated with a private healthcare regime in Colombia has markedly increased. Future studies should evaluate whether the large number of patients with NVAF starting NOAC treatment on a reduced dose are done so appropriately.

Bleeding risk after percutaneous breast needle biopsy in patients on anticoagulation therapy

Image-guided core needle biopsy (CNB) is the standard of care procedure for tissue diagnosis of suspicious breast lesions. While complications are exceedingly rare, the most common complications include bleeding and hematoma formation. With an increasing number of patients on anticoagulation therapy (AT), it is important to determine whether continuation of these medications during CNB increases bleeding risk. While previous studies have demonstrated the safety in continuation of AT during CNB, American College of Radiology (ACR) guidelines recommend practitioners decide whether cessation is necessary on a case-by-case basis as this may put patients at risk for thromboembolic events. The purpose of this review is to analyze the literature on anticoagulation and bleeding risk during CNB to guide clinical practice.

Barriers and facilitators to optimal oral anticoagulant management: a scoping review

Oral anticoagulants (OACs) are high alert medications and require high-quality management to optimize health outcomes. The objective of this scoping review was to identify barriers and facilitators (B&Fs) associated with the quality of OAC management. We searched MEDLINE, EMBASE, and CINAHL databases until July 12, 2018, and cross-referenced the bibliographies of the retrieved studies. We included quantitative and qualitative studies that assessed B&Fs to OAC management. The study selection and data extraction processes were performed in duplicate. Analyses included measuring the prevalence of reported B&Fs from studies reporting quantitative data, identifying B&Fs in narrative analyses, and identifying their impact on important outcomes of OAC management. B&Fs were coded and aggregated to higher-level themes using a consensus approach. Factors were described as "key" if they were statistically associated with important outcomes in a randomized trial or observational study. We included 62 studies-three randomized clinical trials (RCTs), 46 observational studies (cross-sectional studies, cohort studies, and case-control studies), 11 qualitative studies, and two mixed-methods studies. Factors identified could be grouped into four themes-therapy-related, patient-related, healthcare provider-related, and health system-related. Key barriers to optimal OAC management were mostly patient-related, whereas interventions focused on education or implementing protocols were shown through RCTs to be effective at improving knowledge scores of OAC patients. While multiple barriers and some facilitators were identified in this review, none was proven to be associated with clinical outcomes. With this in mind, individual physicians may wish to address the key barriers in their practice as a quality improvement initiative but system-wide or policy changes should await high-quality evidence. Future trials should address these factors.Systematic review registration: PROSPERO CRD42017069043.

Impact of gene polymorphisms in drug-metabolizing enzymes and transporters on trough concentrations of rivaroxaban in patients with atrial fibrillation

Rivaroxaban is excreted from the body via multiple pathways involving glomerular filtration, drug-metabolizing enzymes and transporters. In this study, we aimed to examine the impact of single nucleotide polymorphisms in P-glycoprotein, breast cancer resistance protein, cytochrome P450 (CYP) 3A5 and CYP2J2 on the pharmacokinetics of rivaroxaban. Eighty-six patients with non-valvular atrial fibrillation (NVAF) undergoing AF catheter ablation were enrolled in this study. In these analyses, the dose-adjusted plasma trough concentration ratio (C_0h /D) of rivaroxaban was used as the pharmacokinetic index. The median (quartile range) rivaroxaban C_0h /D was 3.39 (2.08-5.21) ng/mL/mg (coefficient of variation: 80.5%). The C_0h /D did not differ significantly among ABCB1 c.3435C>T, c.2677G>A/T, c.1236C>T, ABCG2 c.421C>A, CYP3A5*3 and CYP2J2*7 genotypes. Stepwise selection multiple linear regression analysis showed that the estimated glomerular filtration rate was the only independent factor influencing the C_0h /D of rivaroxaban (R²  = 0.152, P < 0.001). There was a significant correlation between the C_0h of rivaroxaban and prothrombin time (PT) (rho = 0.357, P = 0.001). In patients with NVAF, pharmacokinetic genotype tests are unlikely to be useful for prediction of the C_0h of rivaroxaban.

Changes in Anticoagulant Utilization Among United States Nursing Home Residents With Atrial Fibrillation From 2011 to 2016

Background

Nursing home residents with atrial fibrillation are at high risk for ischemic stroke and bleeding events. The most recent national estimate (2004) indicated less than one third of this high‐risk population was anticoagulated. Whether direct‐acting oral anticoagulant (DOAC) use has disseminated into nursing homes and increased anticoagulant use is unknown.

Methods and Results

A repeated cross‐sectional design was used to estimate the point prevalence of oral anticoagulant use on July 1 and December 31 of calendar years 2011 to 2016 among Medicare fee‐for‐service beneficiaries with atrial fibrillation residing in long‐stay nursing homes. Nursing home residence was determined using Minimum Data Set 3.0 records. Medicare Part D claims for apixaban, dabigatran, edoxaban, rivaroxaban, and warfarin were identified and point prevalence was estimated by determining if the supply from the most recent dispensing covered each point prevalence date. A Cochran‐Armitage test was performed for linear trend in prevalence. On December 31, 2011, 42.3% of 33 959 residents (median age: 85; Q1 79, Q3 90) were treated with an oral anticoagulant, of whom 8.6% used DOACs. The proportion receiving treatment increased to 47.8% of 37 787 residents as of December 31, 2016 (P<0.01); 48.2% of 18 054 treated residents received DOACs. Demographic and clinical characteristics of residents using DOACs and warfarin were similar in 2016. Half of the 8734 DOAC users received standard dosages and most were treated with apixaban (54.4%) or rivaroxaban (35.8%) in 2016.

Conclusions

Increases in anticoagulant use among US nursing home residents with atrial fibrillation coincided with declining warfarin use and increasing DOAC use.

Comparative effects of telemedicine and face-to-face warfarin management: A systematic review and network meta-analysis

OBJECTIVE

To determine the comparative effects of different types of telemedicine on anticoagulation control and adverse outcomes in patients taking warfarin.

DATA SOURCES

A systematic search was conducted in PubMed, the Cochrane library, EMBASE, CINAHL, OpenGrey, and DART-Europe from inception to September 2019.

STUDY SELECTION

Randomized controlled trials, quasi-experimental and cohort studies were included if they evaluated the effect of telemedicine in patients using warfarin for 3 months or more.

METHODS

Two reviewers extracted and assessed the quality of studies by means of the Cochrane Effective Practice and Organization of Care Group. Network meta-analyses were performed using a random-effects model. Surface under the cumulative ranking curve (SUCRA) methods were used to rank different telemedicine types.

RESULTS

Of the 14,673 articles retrieved, 12 studies involving 11,478 patients met the inclusion criteria. The 5 types of telemedicine categorized were 1) laboratory draw with individual telephonic follow-up by health care (HC) providers (Lab/Tel/HC); 2) laboratory draw with individual telephonic follow-up with periodic, routine routine face-to-face (F2F) visit (Lab/Tel+F2F/HC); 3) laboratory draw with individual and group follow-up via online access (Lab/Online/HC); 4) patient self-test (PST) with telephonic or Web-based follow-up by automated management system (PST/Tel-Online/Auto); and 5) PST with telephonic follow-up by HC provider (PST/Tel/HC). PST/Tel-Online/Auto appears to be superior to F2F for TTR (mean difference 8.78%; 95% CI 0.06%-17.50%) and Lab/Online/HC for in-range INR (odds ratio 2.59; 95% CI 1.04-6.46). The SUCRAs suggested that PST/Tel-Online/Auto was preferred for both TTR and INR, at 84.2% and 93.9%, respectively, whereas Lab/Tel/HC was preferred to prevent major bleeding (74.1%) or thromboembolic event (70.7%).

CONCLUSION

According to the current evidence of uncertain quality, the best effects on anticoagulation control and adverse outcomes were achieved from different types of telemedicine. Variations in the effects of telemedicine on diverse outcomes should be considered before implementing telemedicine interventions in patients taking warfarin.

Reversal strategies and outcomes in patients with atrial fibrillation and warfarin-associated intracranial hemorrhage

PURPOSE

Evaluate reversal strategies in atrial fibrillation (AF) patients with warfarin-associated intracranial hemorrhage (ICH) in clinical care.

MATERIALS AND METHODS

Observational cohort of AF patients with warfarin-associated ICH at two referral hospitals (2007-2010), with patient features, reversal agents, and outcomes collected from medical records.

RESULTS

Among 498 ICH patients 403 received fresh frozen plasma (FFP) without 3-factor prothrombin complex concentrates (PCCs) or recombinant factor VIIa (rFVIIa), 65 received PCCs or rFVIIa, mostly with FFP, and 30 received no acute reversal agents. Median time from presentation to reversal agent administration was 3.4 h (IQR 2.3-5.3). INR was reversed to ≤1.4 by 6 h post-presentation in 46% of patients receiving PCCs/rFVIIa versus 15% receiving FFP alone (p<0.0001). Among PCCs/rFVIIa recipients, 31% died in-hospital vs. 24% receiving FFP alone (p=0.27). Adjusted OR for death accounting for age and Glasgow Coma Score was 0.78 (0.36-1.69) for PCCs/rFVIIa vs FFP only and 1.16 (0.59-2.27) comparing those reaching vs. not reaching INR ≤ 1.4 at 6 h.

CONCLUSIONS

Treatment with PCCs/rFVIIa led to faster INR reversal than treatment with FFP alone. Neither treatment with PCCs/rFVIIa nor rapid INR reversal was associated with improved survival. Delays receiving PCCs may largely eliminate the benefit of treatment.

Improved outcomes after radiotherapy for prostate cancer: Anticoagulation, antiplatelet therapy, and platelet count as key factors in disease progression

BACKGROUND

Several studies have suggested that antiplatelet (AP) or anticoagulant (AC) therapy may improve outcome in men with prostate cancer. We evaluated the effects of AP/AC therapy and tested the hypothesis that platelet count may also be associated with outcomes.

METHODS

A total of 482 patients received primary radiotherapy (median dose 72 Gy) for nonmetastatic prostate cancer; 49% received androgen deprivation therapy. NCCN risk was low/intermediate/high risk in 39%/39%/22%. AP/AC therapy and platelet counts were analyzed with respect to freedom from biochemical failure (FFBF, nadir+2), distant metastasis (FFDM), and cause specific survival (CSS).

RESULTS

After a median follow-up of 103 months, 10-year FFBF, FFDM, and CSS were 77%, 92%, and 96%, respectively. The 10-year cumulative incidence of BF and DM (with death as a competing event) was 19% and 7.0%, respectively. The 32% of men on AP/AC therapy had a lower incidence of 10-year BF (P = .016) and a trend toward a lower incidence of DM (P = .084) and CSS (P = .091). In the entire cohort, lowest platelet quartile (platelet count <187) was associated with higher 10-year BF (31% vs 16%, P = .0042) but not DM (9.4% vs 5.2%, P = .22) nor CSS (P = .76) compared with those patients with platelet count ≥187. AP/AC therapy was associated with a larger absolute reduction in BF for men with lowest platelet quartile (10-year BF of 21% vs 38%, P = .092) vs platelet ≥187 (10-year BF of 10% vs 18%, P = .053). Lowest platelet quartile remained associated with higher BF and DM on multivariable analysis controlling for risk category, WBC, and Hg.

CONCLUSION

AP/AC was associated with improved FFBF. Low platelet count was associated with inferior FFBF and FFDM after prostate radiotherapy. This association was tempered when antiplatelet and anticoagulant therapy was administered.

Evaluating the quality of systematic reviews and meta-analyses published on direct oral anticoagulants in the past 5 years

Systematic reviews (SRs) have been reported with increasing frequency as a means of collating studies which may have been performed over different period of times, in different geographical areas and by different groups of investigators. As SRs have become more common, quality metrics such as Assessing the Methodological Quality of Systematic Reviews (AMSTAR) have become available for these reviews. AMSTAR is an 11-point checklist that assesses the methodological and reporting quality of a SR. In clinical practice, direct oral anticoagulants (DOACs) have been increasingly used for the treatment and prevention of both venous and arterial thromboembolism. We sought to evaluate the quality of SRs published on DOACs using the AMSTAR criteria. A comprehensive search of Medline, EMBASE and the Cochrane Database of Systematic Reviews from January 2013 to February 2019 was performed. Two reviewers independently screened titles and abstracts and subsequently full texts for eligibility. Data extraction was also completed in duplicate. Categories of extracted data included AMSTAR rating, journal of publication, year of publication, number of studies included in the SR, reporting adherence to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, number of times the paper was cited and journal impact factor. A total of 3729 articles were identified, of which 250 were eligible for analysis. SR quality was highly variable with mean (SD) AMSTAR score of 5.68/11 (2.21). Reporting adherence to PRISMA guideline correlated with a moderate (5-8) or high quality (9-11) (OR=4.19, p<0.01) AMSTAR score. The methodological quality of DOACs was generally rated to be low-moderate, and improved adherence to AMSTAR methodological practices are strongly recommended.

Trends in oral anticoagulant prescribing in individuals with type 2 diabetes mellitus: a population-based study in the UK

OBJECTIVE

To evaluate oral anticoagulant (OAC) prescribing trends in type 2 diabetes mellitus (T2DM) in the UK from 2001 to 2015.

DESIGN

A cross-sectional drug utilisation study.

SETTING

Electronic health records from The Health Improvement Network primary care database in the UK.

PARTICIPANTS

Individuals with T2DM who received a record of OAC prescription.

OUTCOME MEASURES

The prescribing trends of OAC medications in individuals with T2DM were examined from 2001 to 2015, stratified by age, gender and therapeutic classifications.

RESULTS

A total of 361 635 individuals with T2DM were identified, of whom 36 570 were prescribed OAC from 2001 to 2015. The prevalence of OAC prescribing increased by 50.0%, from 1781 individuals receiving OAC prescriptions (IROACP) (4.4 (95% CI 4.2 to 4.6) per 100 persons) in 2001, to 17 070 IROACP (6.6 (95% CI 6.5 to 6.7) per 100 persons) in 2015. The prevalence of warfarin prescribing decreased by 14.0%, from 1761 individuals receiving warfarin prescriptions (IRWP) (98.9 (95% CI 98.4 to 99.4) per 100 persons) in 2001, to 14 533 IRWP (85.1 (95% CI 84.6 to 85.7) per 100 persons) in 2015. This corresponded with increased prescribing of direct oral anticoagulants (DOACs), from 18 individuals receiving DOAC prescriptions (IRDOACP) (0.1 (95% CI 0.08 to 0.23) per 100 persons) in 2010, to 3016 IRDOACP (17.6 (95% CI 17.1 to 18.2) per 100 persons) in 2015, during the same period.

CONCLUSIONS

Prescribing of OACs in individuals with T2DM increased from 2001 to 2015. Since the introduction of DOACs, there has been a clear shift in prescribing towards these agents. Future studies are needed to assess the safety of coadministration of OAC medications and antidiabetic therapy with T2DM.

Sulfonylureas and Metformin Were Not Associated With an Increased Rate of Serious Bleeding in Warfarin Users: A Self-Controlled Case Series Study

Drug interactions between warfarin and sulfonylureas are suggested by pharmacokinetic information and prior studies. However, clinical evidence on the association of such interactions and the risk of bleeding is lacking. Using healthcare claims data from 5 US Medicaid programs from 1999-2011 and a self-controlled case series design with warfarin as an object drug, we calculated confounder-adjusted rate ratios (RRs) for concomitant use of sulfonylureas and metformin for 3 outcomes separately: (i) serious bleeding as a composite outcome of gastrointestinal bleeding (GIB) and nontraumatic intracranial hemorrhage (ICH); (ii) GIB; and (iii) ICH. In 6,463 warfarin users experiencing serious bleeding, an increased rate of serious bleeding was not associated with concomitant use of glimepiride (RR: 0.93; 95% confidence interval (CI) 0.75-1.15), glipizide (RR: 0.97; 95% CI 0.84-1.13), glyburide (RR: 0.89; 95% CI 0.76-1.06), or metformin (RR: 0.85; 95% CI 0.76-0.96), nor was the occurrence of the component outcomes of GIB or ICH. These results suggest that use of sulfonylureas or metformin was not associated with an increased rate of serious bleeding in warfarin users.

Stroke prevention in atrial fibrillation changes after dabigatran availability in China: The GLORIA-AF registry

Background

Until the approval of dabigatran etexilate, treatment choices for stroke prevention in patients with atrial fibrillation (AF) were vitamin K antagonists (VKAs) or antiplatelet drugs. This analysis explored whether availability of non-vitamin K antagonist oral anticoagulants post-dabigatran approval was associated with changing treatment patterns in China.

Methods

Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF) collected data on antithrombotic therapy choices for patients with newly diagnosed nonvalvular AF at risk for stroke. In China, enrollment in phase 1 (before dabigatran approval) and phase 2 (after dabigatran approval) occurred from 2011 to 2013 and 2013 to 2014, respectively. Analyses were restricted to sites within China that contributed patients to both phases. The weighted average of the site-specific results was estimated for standardization. Sensitivity analyses used multiple regression.

Results

Thirteen sites participated in both phase 1 (419 patients) and phase 2 (276 patients), 76.1% and 16.0% were known to be at high risk for stroke (CHA₂DS₂-VASc ≥2) and bleeding (HAS-BLED ≥3); 55.5% were male. In phase 1, 16.7%, 61.6%, and 21.7% of patients were prescribed oral anticoagulants (OACs), antiplatelet agents, and no treatment, respectively. Respective proportions were 26.4%, 40.6%, and 33.0% in phase 2. The absolute increase in the site-standardized proportion of patients prescribed OACs after dabigatran availability was 9.9% (95% confidence interval [CI]: 3.7%-16.0%). There was a standardized 17.3% (95% CI: -24.3% to -10.4%) absolute decrease in antiplatelet agent use.

Conclusions

There was an increase in OAC and decrease in antiplatelet agent prescription since dabigatran availability in China. However, a large proportion of AF patients at risk for stroke remained untreated.

DRIMC: an improved drug repositioning approach using Bayesian inductive matrix completion

Motivation

One of the most important problems in drug discovery research is to precisely predict a new indication for an existing drug, i.e. drug repositioning. Recent recommendation system-based methods have tackled this problem using matrix completion models. The models identify latent factors contributing to known drug-disease associations, and then infer novel drug-disease associations by the correlations between latent factors. However, these models have not fully considered the various drug data sources and the sparsity of the drug-disease association matrix. In addition, using the global structure of the drug-disease association data may introduce noise, and consequently limit the prediction power.

Results

In this work, we propose a novel drug repositioning approach by using Bayesian inductive matrix completion (DRIMC). First, we embed four drug data sources into a drug similarity matrix and two disease data sources in a disease similarity matrix. Then, for each drug or disease, its feature is described by similarity values between it and its nearest neighbors, and these features for drugs and diseases are mapped onto a shared latent space. We model the association probability for each drug-disease pair by inductive matrix completion, where the properties of drugs and diseases are represented by projections of drugs and diseases, respectively. As the known drug-disease associations have been manually verified, they are more trustworthy and important than the unknown pairs. We assign higher confidence levels to known association pairs compared with unknown pairs. We perform comprehensive experiments on three benchmark datasets, and DRIMC improves prediction accuracy compared with six stat-of-the-art approaches.

Availability and implementation

Source code and datasets are available at https://github.com/linwang1982/DRIMC.

Supplementary information

Supplementary data are available at Bioinformatics online.

Standardized warfarin monitoring decreases adverse drug reactions

Background

While warfarin is the most commonly prescribed medication to prevent thromboembolic disorders, the risk of adverse drug reactions (ADR) poses a serious concern. This prospective study evaluated how primary care providers (PCP) and cardiologists at our Institution managed patients treated with warfarin with the goal of decreasing the number of warfarin ADRs.

Methods

A multidisciplinary anticoagulation task force was established at our Institution in 2014 to standardize warfarin monitoring and management. Between 2013 and 2017, we analyzed patients who were prescribed warfarin by their PCP or cardiologist upon hospital discharge and in the ambulatory setting to determine the international normalized ratio (INR) within 5, 10, and 30 days after discharge, time in therapeutic range (TTR), number of severe warfarin ADRs, and total and average cost reduction of all severe warfarin ADRs to determine whether there was an organizational cost savings following the implementation of standardized warfarin care.

Results

The warfarin ADR rate significantly decreased over the 5-year period, from 3.8 to 0.98% (p < 0.0001). The proportion of warfarin prescriptions out of all anticoagulants significantly decreased, from 72.2 to 42.1% (p < 0.001). The proportion of individuals who received an INR at 5, 10, and 30 days after hospital discharge compared to the total number of patients prescribed warfarin significantly increased (p < 0.001). The total cost of severe warfarin ADRs decreased by 57.6% between 2013 and 2017.

Conclusions

This study serves as a model to reduce the number of severe warfarin ADRs by the following tactics: (1) educating PCPs and cardiologists about evidence-based guidelines for warfarin management, (2) increasing the use of our Institution’s electronic warfarin module, and (3) enhancing patient compliance with obtaining INR.