Prevalence and Risk Factors of Inappropriate Drug Dosing among Older Adults with Dementia or Cognitive Impairment and Renal Impairment: A Systematic Review

Background: Potentially inappropriate medication prescribing is prevalent and well studied in older adults. However, limited data are available on inappropriate drug dosing in those with dementia or cognitive impairment and renal impairment. Objectives: We aimed to examine the prevalence of, and factors associated with, inappropriate drug dosing in older patients with dementia or cognitive impairment and renal impairment. Methods: We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline and the Cochrane Handbook for Systematic Reviews of Interventions. We searched Medline, Embase, CINAHL, and PubMed for studies on inappropriate drug dosing in older patients with dementia or cognitive impairment and renal impairment, published from 1 January 2000 to 31 August 2024, with English language restriction following the PICOS search strategy. Two reviewers independently screened all titles and abstracts, extracted data from included studies, and undertook quality assessment using the Joanna Briggs Institute (JBI) tool. Descriptive statistics were used to summarise and present findings. Results: In total, eight retrospective cohort studies were included. Of the total number of patients with dementia who had renal impairment (n = 5250), there were 2695 patients (51.3%; range: 0-60%) who had inappropriate drug dosing. Drugs commonly prescribed in inappropriate doses in patients with dementia who had renal impairment included memantine, baclofen, nonsteroidal anti-inflammatory drugs (NSAIDs), metformin, digoxin, morphine, and allopurinol. The studies did not identify statistically significant risk factors for inappropriate drug dosing. Conclusions: Inappropriate drug dosing among older adults with dementia or cognitive impairment and renal impairment appears to occur frequently. While our findings should be interpreted with caution owing to the small number of studies and substantial heterogeneity, proactive prevention, recognition, and management of inappropriate drug dosing in this population is warranted.

Cutaneous Ulcer Caused by Apixaban Treatment Is Resolved after Replacement with Dabigatran

Nowadays, novel oral anticoagulants (NOACs) have shown improved safety profile and efficacy compared to vitamin K antagonists in the prevention of thromboembolic events occurring during different pathological conditions. However, there are concerns and safety issues, mostly related to adverse events following interactions with other drugs, in real-world practice. We report the case of an 83-year-old woman who developed a non-bleeding leg ulcer not caused by trauma or other evident pathological conditions after 10 days of treatment with apixaban 5 mg/q.d. She was switched from apixaban to dabigatran and the leg ulcer rapidly improved and completely cicatrized in 40 days. The resolution of the ulcer and the toleration of dabigatran therapy suggest an apixaban-specific reaction; however, the pathological mechanism of ulcer onset is currently unclear. Careful evaluation of hospital databases of Molise region (Southern Italy) hospitals identified two similar cases between 2019 and 2021. These cases underline the necessity of careful post-marketing surveillance, considering the rapidly increasing number of patients treated with NOACs and patient’s risk factors such as old age, high polypharmacy rate, co-morbidities, and peculiar genetic background related to NOACs pharmacokinetic features.

Comparative efficacy and safety of warfarin care bundles and novel oral anticoagulants in patients with atrial fibrillation: a systematic review and network meta-analysis

Warfarin care bundles (e.g. genotype-guided warfarin dosing, patient’s self-testing [PST] or patient’s self-management [PSM] and left atrial appendage closure) are based on the concept of combining several interventions to improve anticoagulation care. NOACs are also introduced for stroke prevention in atrial fibrillation (SPAF). However, these interventions have not been compared in head-to-head trials yet. We did a network meta-analysis based on a systematic review of randomized controlled trials comparing anticoagulant interventions for SPAF. Studies comparing these interventions in adults, whether administered alone or as care bundles were included in the analyses. The primary efficacy outcome was stroke and the primary safety outcome was major bleeding. Thirty-seven studies, involving 100,142 patients were assessed. Compared to usual care, PSM significantly reduced the risk of stroke (risk ratio [RR] 0.24, 95% CI 0.08–0.68). For major bleeding, edoxaban 60 mg (0.80, 0.71–0.90), edoxaban 30 mg (0.48, 0.42–0.56), and dabigatran 110 mg (0.81, 0.71–0.94) significantly reduced the risk of major bleeding compared with usual warfarin care. Cluster rank plot incorporating stroke and major bleeding outcomes indicates that some warfarin care bundles perform as well as NOACs. Both interventions are therefore viable options to be considered for SPAF. Additional studies including head-to-head trials and cost-effectiveness evaluation are still warranted.

Management of Hemorrhage Related to Direct Action Oral Anticoagulant Medication

Introduction: Direct Oral Anticoagulant – DOACs) are a new class of anticoagulant that directly inhibit the trombine (dabigatran) or Xa factor (rivaroxabane , edoxabane and apixabane) in the coagulation cascade. These medications are being more frequently used for the treatment and prevention of thrombolytic events, mainly in patients with atrial fibrillation, in substitute to varfrine or other vitamin K antagonists (VKAs). Although the incidence of hemorrhage is higher in AVKs than in DOACs, these events may also occur in this group, even in the form of intracranial hemorrhage (ICH), with risk of death. Nowadays, DOACs indications have progressively enhanced and the availability of their specific reverse agents certainly will enhance the safety of their usage. Idarucizumab, reverse agent of dabigatrane, and alpha andexanet, reverse agent of Xa factor, have been approved by the Food and Drug Administration in the United States and ciraparantag may be approved in a near future. Objective: To review the literature on the manage of hemorrhage related to the use of DOACs. Methods: Review of literature that used articles from 1998 to 2017, from several platforms and journals. Conclusion: DOACs constitute a great advance in prophylaxis and treatment of thrombolytic diseases, which presents elevated morbidymortality, and hemorrhages are the main adverse events related to their usage, being rarely necessary the immediate reverse of the anticoagulation. However, the existence of DOACs specific reverse agents enhance the safety of patients, whose anticoagulation may be rapidly reversed if necessary.

Manejo das Hemorragias Relacionadas aos Anticoagulantes Orais de Ação Direta

Introdução: Os anticoagulantes orais diretos (direct oral anticoagulant – DOACs) são uma nova classe de anticoagulantes que inibem diretamente a trombina (dabigatrana) ou o fator Xa (rivaroxabana, edoxabana e apixabana) na cascata da coagulação. Esses estão sendo cada vez mais utilizados para tratamento e prevenção de eventos tromboembólicos, principalmente em pacientes com fibrilação atrial, em substituição à varfarina ou outros antagonistas de vitamina K (AVKs). Embora a incidência de hemorragias seja maior nos AVKs do que nos DOACs, elas também podem ocorrer nesse grupo, até mesmo na forma de hemorragia intracraniana (HIC) com risco de morte. Atualmente as indicações dos DOACs vêm aumentando progressivamente, e a disponibilização de seus agentes reversores específicos certamente aumentará a segurança e, consequentemente, sua utilização. O idarucizumab, reversor da dabigatrana, e o andexanet alfa, reversor dos inibidores do fator Xa, foram aprovados pelo Food and Drug Administration (FDA) dos Estados Unidos e o ciraparantag poderá ser aprovado em um futuro próximo. Objetivo: Revisar a literatura sobre o manejo da hemorragia relacionada ao uso dos DOACs. Métodos: Revisão da literatura que utilizou artigos de 1998 a 2017, de diversas plataformas e revistas. Conclusão: Os DOACs constituem um grande avanço na profilaxia e tratamento da doença tromboembólica, que cursa com elevada morbimortalidade, e as hemorragias são os principais eventos adversos relacionados ao seu uso, sendo raramente necessária a reversão imediata da anticoagulação. No entanto, a existência dos reversores específicos dos DOAcs aumenta a segurança dos pacientes, que poderão ter sua anticoagulação revertida rapidamente, se necessário.

The evolving role of dabigatran etexilate in clinical practice

INTRODUCTION

Stroke and venous thromboembolism (VTE) affect millions of patients. The vitamin K antagonist, warfarin, has been the main oral anticoagulant used to treat these conditions despite many limitations associated with its use. Recently, multiple novel oral anticoagulants have been approved and are reshaping how patients with atrial fibrillation (AF) at risk of stroke and patients with VTE are treated. The direct thrombin inhibitor, dabigatran etexilate , is among these novel agents that have been developed to overcome limitations with warfarin.

AREAS COVERED

In this article, authors describe the pharmacokinetic and pharmacodynamic properties of dabigatran etexilate and summarize the clinical evidence and controversy surrounding its use in the US, Canada and Europe.

EXPERT OPINION

Dabigatran has demonstrated similar efficacy and safety to enoxaparin for VTE prevention in patients undergoing hip and knee arthroplasty, and to warfarin for the treatment of VTE. Dabigatran (110 mg) is noninferior and dabigatran (150 mg) is superior to warfarin for stroke prevention in patients with nonvalvular AF, with a lower rate of intracranial hemorrhage reported at both doses. Apixaban, rivaroxaban and edoxaban provide alternate anticoagulant options to dabigatran. While there are many similarities, there are also significant differences to consider in agent selection based on patient-specific characteristics.

A proposal for dose-adjustment of dabigatran etexilate in atrial fibrillation guided by thrombin time

Dabigatran is an oral anticoagulant that is increasingly used for atrial fibrillation (AF). Presently, many authorities state that routine laboratory coagulation monitoring is not required. However, data have recently been published demonstrating that higher trough plasma dabigatran concentrations are associated with lower thromboembolic and higher haemorrhagic event rates. Using these data, we simulate a range of AF patients with varying risks for these events and derive a target range of trough plasma dabigatran concentrations (30-130 μg l(-1) ). Finally, we propose that a conventional screening coagulation assay, the thrombin time (TT), can be used to discern whether or not patients are within this range of dabigatran concentrations.

Coagulation assays and plasma fibrinogen concentrations in real-world patients with atrial fibrillation treated with dabigatran

AIMS

In patients with atrial fibrillation prescribed dabigatran, the aim was to examine the correlation between plasma dabigatran concentrations and the three screening coagulation assays [international normalized ratio (INR), activated partial thromboplastin time (aPTT) and thrombin time (TT)] as well as the dilute thrombin time (dTT) and to examine the contribution of plasma fibrinogen concentrations to the variability in TT results.

METHODS

Plasma from patients with atrial fibrillation on dabigatran were analysed for clotting times and concentrations of fibrinogen and dabigatran. Correlation plots (and associated r(2) values) were generated using these data. The variability in TT results explained by fibrinogen concentrations was quantified using linear regression.

RESULTS

Fifty-two patients (38-94 years old) contributed 120 samples, with plasma dabigatran concentrations ranging from 9 to 408 μg l(-1) . The r(2) values of INR, aPTT, TT and dTT against plasma dabigatran concentrations were 0.49, 0.54, 0.70 and 0.95, respectively. Plasma fibrinogen concentrations explained some of the residual variability in TT values after taking plasma dabigatran concentrations into account (r(2) = 0.12, P = 0.02).

CONCLUSIONS

Of the screening coagulation assays, the TT correlated best with plasma dabigatran concentrations. Variability in fibrinogen concentrations accounts for some of the variability in the TT.

Adherence to dabigatran therapy and longitudinal patient outcomes: insights from the veterans health administration

BACKGROUND

Dabigatran is a novel oral anti-coagulant (NOAC) that reduces risk of stroke in patients with non-valvular atrial fibrillation (NVAF). It does not require routine monitoring with laboratory testing which may have an adverse impact on adherence. We aimed to describe adherence to dabigatran in the first year after initiation and assess the association between non-adherence to dabigatran and clinical outcomes in a large integrated healthcare system.

METHODS

We studied a national cohort of 5,376 patients with NVAF, initiated on dabigatran between October-2010 and September-2012 at all Veterans Affairs hospitals. Adherence to dabigatran was calculated as proportion of days covered (PDC) and association between PDC and outcomes was assessed using standard regression techniques.

RESULTS

Mean age of the study cohort was 71.3 ± 9.7 years; 98.3% were men and mean CHADS2 score was 2.4 ± 1.2 (mean CHA2DS2VASc score 3.2 ± 1.4). Median PDC was 94% (IQR 76%-100%; mean PDC 84% ± 22%) over a median follow-up of 244 days (IQR 140-351). A total of 1,494 (27.8%) patients had a PDC <80% and were classified as non-adherent. After multivariable adjustment, lower adherence was associated with increased risk for combined all-cause mortality and stroke (HR 1.13, 95% CI 1.07-1.19 per 10% decrease in PDC). Adherence to dabigatran was not associated with non-fatal bleeding or myocardial infarction.

CONCLUSIONS

In the year after initiation, adherence to dabigatran for a majority of patients is very good. However, 28% of patients in our cohort had poor adherence. Furthermore, lower adherence to dabigatran was associated with increased adverse outcomes. Concerted efforts are needed to optimize adherence to NOACs.

[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.

Evaluation of dabigatran utilization and risk among hospitalized patients

BACKGROUND

Few data exist to evaluate the use of dabigatran among hospitalized patients and this population that may be at increased risk for toxicity or reduced efficacy. As such, the objectives of this study were to describe the characteristics of hospitalized patients prescribed dabigatran and to compare select characteristics with patients included in the Randomized Evaluation of Long-Term Anticoagulation (RE-LY) phase III clinical trial.

METHODS

A cross-sectional study was performed at Upstate University Hospital. Select patient characteristics, including age, renal function, and drug interaction exposure, were compared with those for patients in the RE-LY trial.

RESULTS

The study included 140 patients. Mean age was 69.7 years (SD = 13.8) and 72 (51.4%) were male. The mean CHADS2 score was 2.48 as compared with 2.2 in RE-LY. Significantly more patients in our study had moderate to severe renal dysfunction (creatinine clearance [CrCl] < 50 mL/min) as compared with the RE-LY trial (27.5% vs 19.4%, P = .0207) when analyzing our study patients' worst recorded CrCl. Among the 29 patients prescribed dose-adjusted dabigatran, 3 were correctly dose adjusted, 2 were overdosed, and 26 were underdosed. At least 1 pharmacokinetic drug interaction with dabigatran occurred in 110 study patients (78.6%). Use of proton pump inhibitors was more predominant in our study population when compared with RE-LY (64.3% vs 13.9%, P < .0001).

CONCLUSIONS

Hospitalized patients exhibit multiple characteristics that place them at heightened risk for altered dabigatran drug concentrations and may have a heightened risk for clinical sequelae related to dabigatran use.

Pharmacokinetic and pharmacodynamic drug interactions with new oral anticoagulants: what do they mean for patients with atrial fibrillation?

OBJECTIVE

To review pharmacokinetic and pharmacodynamic drug-drug interactions (DDIs) involving new oral anticoagulants for atrial fibrillation.

DATA SOURCES

A literature search was conducted via PubMed and the Cochrane database to identify DDI studies using the terms drug interactions, dabigatran, rivaroxaban, and apixaban. Prescribing information and Food and Drug Administration briefing documents were used to supplement published data.

STUDY SELECTION AND DATA EXTRACTION

English publications identified on Medline from 2005 up to August 2013 and US prescribing information for approved oral anticoagulants.

DATA SYNTHESIS

Articles reviewed focused on drugs affecting the permeability glycoprotein (P-gp) efflux transporter protein and/or cytochrome P (CYP) 450 3A4 enzymes, and pharmacodynamic DDIs when drugs are administered concomitantly. Phase I DDI studies have reported pharmacokinetic DDIs mediated by P-gp alone (dabigatran etexilate) or in combination with CYP3A4 enzymes (rivaroxaban and apixaban). Dabigatran etexilate should not be administered with any P-gp inhibitor in patients with severe renal impairment. Briefing documents indicate that rivaroxaban and apixaban should not be used with drugs that are strong inhibitors of both P-gp and CYP3A4. DDI studies involving rifampicin suggest that rivaroxaban and apixaban should be avoided when strong inducers of P-gp and CYP3A4 are used concurrently. Concomitant use of apixaban and strong dual inhibitors of P-gp and CYP3A4 should be avoided or the dose reduced. Five randomized clinical trials report additive effects with rivaroxaban, dabigatran, and apixaban when used concomitantly with antiplatelet agents; bleeding rates have been found to be higher, especially with dual antiplatelet therapy.

CONCLUSIONS

Awareness of drugs that alter the function of the P-gp efflux transporter protein and CYP3A4 enzymes and provide additive effects should enable prescribers to anticipate and avoid potential DDIs involving the new oral anticoagulants. To this end, briefing documents and prescribing information have applied cautionary measures for individuals treated with these newer anticoagulants.

Safe Use of Hemodialysis for Dabigatran Removal before Cardiac Surgery

OBJECTIVE:

To describe a case in which hemodialysis was performed before cardiac transplantation in an attempt to reverse the effects of dabigatran and reduce the risk of bleeding associated with surgery.

CASE SUMMARY:

A 59-year-old female with heart failure and atrial fibrillation was admitted for orthotropic heart transplant. She had been stable at home with continuous milrinone therapy 0.25 μg/kg/min, amiodarone 200 mg twice daily, and dabigatran 150 mg twice daily for stroke prevention secondary to atrial fibrillation. Upon notification of organ availability, the patient was admitted to the hospital for transplant surgery, with her last dose of dabigatran taken approximately 36 hours before admission. Coagulation studies indicated normal activated partial thromboplastin time, slightly elevated international normalized ratio of 1.2, and elevated thrombin time (TT) of 90.6 seconds (upper limit of normal 19.9 seconds). A hemodialysis catheter was emergently placed and dialysis was initiated. One hour after initiation, TT decreased to 65.5 seconds. After 2.5 hours of dialysis, TT further decreased to 60.2 seconds; at that time, the patient underwent transplantation with no abnormal bleeding during or following surgery.

DISCUSSION:

Minimal data exist on techniques to reverse the effects of dabigatran in cases of bleeding or emergent surgery. This case examines the efficacy of hemodialysis to decrease dabigatran's effect on clotting assays prior to surgery to reduce the risk of bleeding. In this case, a TT of 60.2 seconds with recent dabigatran administration did not result in abnormal bleeding associated with cardiac surgery.

CONCLUSIONS:

To our knowledge, this case report represents the first published data on the effects of hemodialysis on dabigatran removal and reversal of anticoagulation associated with dabigatran before surgery. The routine use of preoperative hemodialysis in patients on dabigatran is not recommended; however, the potential efficacy in such circumstances is supported by the successful results in this case.

Significant Bleeding in Elderly Patient with Atrial Fibrillation Due to Probable Interaction between Dabigatran and Amiodarone

Objective:

To present the case of an elderly patient who developed significant bleeding while receiving a standard dose of dabigatran with concomitant amiodarone therapy.

Case Summary:

A 77-year-old man was admitted for upper gastrointestinal bleeding that presented as coffee ground emesis. A coronary artery bypass graft had been performed 4 weeks earlier, which was well tolerated, except that his postoperative course was complicated by atrial fibrillation, for which amiodarone was initiated; dabigatran was added subsequently. Upon his admission to the hospital, dabigatran was stopped. The patient's bleeding was stabilized and dabigatran 150 mg twice daily was restarted after amiodarone was discontinued. The laboratory was not equipped to measure thrombin clotting time or ecarin clotting time; therefore, the team relied on the measurement of international normalized ratio (INR) and activated partial thromboplastin time to guide therapy based on pharmacokinetic and pharmacodynamic studies of therapeutic dabigatran concentrations. Based on laboratory values the following morning, the team maintained dabigatran 150 mg once daily. Subsequent INR and partial thromboplastin time values were within the desired range. He remained stable, without further evidence of bleeding even after anticoagulation with dabigatran was restarted for atrial fibrillation.

Discussion:

Dabigatran received FDA approval in October 2010 to reduce the risk of stroke and systemic embolization in patients with nonvalvular atrial fibrillation. It has a favorable monitoring profile compared to warfarin. The manufacturer acknowledges the potential for amiodarone to increase the effective concentration of dabigatran because of its inhibition of P-glycoprotein. An objective causality assessment using the Horn Drug Interaction Probability Scale revealed that the interaction was probable.

Conclusions:

A probable interaction suggests that providers should use caution with the coadministration of amiodarone with dabigatran; dose adjustment in the setting of concomitant administration in elderly patients with atrial fibrillation should be considered.

Age- and weight-adjusted warfarin initiation nomogram for ischaemic stroke patients

OBJECTIVES

Specific guidelines for initial dosing of warfarin in ischaemic stroke patients have not been developed. Therefore, we have developed an age- and weight-adjusted warfarin initiation nomogram (AW-WIN) for ischaemic stroke patients and then evaluated the efficacy and safety of AW-WIN compared with physician-determined warfarin dosing (PDWD).

METHODS

The age- and weight-adjusted warfarin initiation nomogram was administered to 104 acute ischaemic stroke patients between January 2008 and February 2009. A historical control group (PDWD) of 96 patients was selected from comparable patients who were discharged with warfarin during the previous year. Time-to-therapeutic international normalized ratios (INRs) and the incidence of excessive anticoagulation were compared in the AW-WIN and PDWD groups.

RESULTS

The general characteristics, risk factors, and stroke mechanism of the AW-WIN and PDWD groups did not differ significantly. The mean time to INR ≥ 2.0 was significantly shorter in the AW-WIN than in the PDWD group (4.9 ± 0.7 vs. 6.2 ± 0.8 days, P = 0.0008). After adjustment for potential confounding variables, the AW-WIN group reached target INR faster than the PDWD group (hazard ratio, 1.76; 95% confidence interval, 1.26-2.45; P = 0.001). The time-to-therapeutic INR ≥1.7 was shorter (P = 0.0002), the proportion of patients with therapeutic INR (2-3) at 5 days was higher (P = 0.002), and the rate of excessive anticoagulation of ≥3.5 INR during hospitalization was lower (P = 0.024) in the AW-WIN than in the PDWD group.

CONCLUSIONS

AW-WIN reduces the time to target INR and the risk of excessive anticoagulation. AW-WIN may be an efficient and safe method of anticoagulation during the acute phase of ischaemic stroke.

Novel oral anticoagulants and their role in clinical practice

The complexities of oral anticoagulation with warfarin have led to the search for more practical alternative agents. Novel direct factor IIa inhibitors and direct factor Xa inhibitors currently in development can be administered at a fixed dose and do not require routine coagulation monitoring and ongoing dosage adjustment to ensure their effectiveness and safety. A number of phase III trials of these agents for the prevention of venous thromboembolism associated with orthopedic surgery and acute medical illness, for the treatment of venous thromboembolism, and for stroke prevention in patients with atrial fibrillation have been completed, with almost universally positive results. If these novel agents are approved for use in the United States, the future of oral anticoagulant therapy will allow a more nuanced approach to drug selection than has been available in the past. Attention to drug interactions and renal function will be required, as methods to measure the presence of these agents are not precise, cannot quantify the degree of anticoagulant present, and are influenced by the changes in serum drug concentrations during the dosing interval. In the future, patient preferences and the pharmacokinetic and pharmacodynamic characteristics of individual drugs will be able to be matched to optimize therapy. These new agents represent a new paradigm for anticoagulation that promises to improve patient care in the long term.

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

Systematic management models such as anticoagulation clinics have emerged in order to optimize warfarin effectiveness and to minimize related complications. Most of these models are structured so that patients come to a clinic for in-person testing and evaluation, thus making this model of care difficult to access and time consuming for many patients. The emergence of portable instruments for measuring anticoagulant effect in capillary whole blood made it possible for patients receiving warfarin to self-monitor the effect of their anticoagulant therapy. Self-monitoring empowers patients, offers the advantage of more frequent monitoring, and increases patient convenience by allowing testing at home and avoiding the need for frequent laboratory and clinic visits. Self-monitoring can entail patient self-testing (PST) and/or patient self-management (PSM). Several studies have evaluated and shown the benefit of both PST and PSM models of care when compared with either routine medical care or anticoagulation clinic management of anticoagulation therapy. Self-monitoring (PSM and/or PST) of anticoagulation results in lower thromboembolic events, lower mortality, and no increase in major bleeding when compared with standard care. Despite favorable results and enhanced patient convenience, the adoption of self-monitoring into clinical practice in the United States has been limited, especially in higher risk, disadvantaged populations. Although the emergence of a multitude of novel oral anticoagulants will permit clinicians to better individualize anticoagulant therapy options by choosing the optimum regimen based on individual patient characteristics, it is also expected that traditional agents will continue to play a role in a significant subset of patients. For those patients treated with traditional anticoagulants such as warfarin, future models of care will entail patient-centered management such as PST and PSM. The incorporation of technology (i.e., Web-based expert systems) is expected to further improve the outcomes realized by PST and PSM. Further studies are needed to explore factors that influence the adoption of self-monitoring in the United States and to evaluate the feasibility and implementation in real-life clinical settings.