Prompt repeat testing after out-of-range INR values: a quality indicator for anticoagulation care

Optimizing warfarin dosing for patients with atrial fibrillation using machine learning

While novel oral anticoagulants are increasingly used to reduce risk of stroke in patients with atrial fibrillation, vitamin K antagonists such as warfarin continue to be used extensively for stroke prevention across the world. While effective in reducing the risk of strokes, the complex pharmacodynamics of warfarin make it difficult to use clinically, with many patients experiencing under- and/or over- anticoagulation. In this study we employed a novel implementation of deep reinforcement learning to provide clinical decision support to optimize time in therapeutic International Normalized Ratio (INR) range. We used a novel semi-Markov decision process formulation of the Batch-Constrained deep Q-learning algorithm to develop a reinforcement learning model to dynamically recommend optimal warfarin dosing to achieve INR of 2.0-3.0 for patients with atrial fibrillation. The model was developed using data from 22,502 patients in the warfarin treated groups of the pivotal randomized clinical trials of edoxaban (ENGAGE AF-TIMI 48), apixaban (ARISTOTLE) and rivaroxaban (ROCKET AF). The model was externally validated on data from 5730 warfarin-treated patients in a fourth trial of dabigatran (RE-LY) using multilevel regression models to estimate the relationship between center-level algorithm consistent dosing, time in therapeutic INR range (TTR), and a composite clinical outcome of stroke, systemic embolism or major hemorrhage. External validation showed a positive association between center-level algorithm-consistent dosing and TTR (R2 = 0.56). Each 10% increase in algorithm-consistent dosing at the center level independently predicted a 6.78% improvement in TTR (95% CI 6.29, 7.28; p < 0.001) and a 11% decrease in the composite clinical outcome (HR 0.89; 95% CI 0.81, 1.00; p = 0.015). These results were comparable to those of a rules-based clinical algorithm used for benchmarking, for which each 10% increase in algorithm-consistent dosing independently predicted a 6.10% increase in TTR (95% CI 5.67, 6.54, p < 0.001) and a 10% decrease in the composite outcome (HR 0.90; 95% CI 0.83, 0.98, p = 0.018). Our findings suggest that a deep reinforcement learning algorithm can optimize time in therapeutic range for patients taking warfarin. A digital clinical decision support system to promote algorithm-consistent warfarin dosing could optimize time in therapeutic range and improve clinical outcomes in atrial fibrillation globally.

The effect of reinforcing an educational programme using telephone follow-up on health-related quality of life of individuals using warfarin: A randomised controlled trial

OBJECTIVES

To evaluate the effect of reinforcing an educational programme through telephone follow-up on health-related quality of life and anxiety and depression symptoms in individuals starting warfarin therapy.

BACKGROUND

Educational interventions have improved quality of life in individuals using warfarin. Few studies have examined the addition of telephone follow-up to enhance educational interventions.

DESIGN

Randomised controlled trial in outpatient setting.

METHODS

Hospitalised adults starting warfarin therapy who agreed to participate received an educational programme about the warfarin treatment. At discharge, they were randomised to receive either five telephone follow-up calls (intervention) or no telephone calls (controls). Both groups were evaluated for health-related quality of life (using Duke Anticoagulation Satisfaction Scale) and symptoms of anxiety and depression (using Hospital Anxiety and Depression Scale) at three and six months post-discharge. Groups were compared at each time by independent-samples t test, and over time by repeated-measures analysis of variance, with time (three and six months), groups (intervention and control) and an interaction between time and group as factors. Level of significance was set at 0.05. The Consolidated Standards of Reporting Trials was used for reporting.

RESULTS

Fifty-two individuals (26 per group) completed the study. There were no statistical differences between groups in health-related quality of life, anxiety and depression symptoms, at both times post-discharge. Participants who received follow-up telephone calls reported better positive psychological impact (a subscale of quality of life) than controls.

CONCLUSIONS

Reinforcing an educational programme with telephone follow-ups did not have an overall effect on health-related quality of life of individuals using warfarin but promoted positive psychological impact.

RELEVANCE TO CLINICAL PRACTICE

The low cost of reinforcing educational programmes with telephone calls and the improvement in positive psychological aspects indicate that this type of intervention is still a promising intervention that could be further investigated and improved.

American Society of Hematology 2018 guidelines for management of venous thromboembolism: optimal management of anticoagulation therapy

BACKGROUND

Clinicians confront numerous practical issues in optimizing the use of anticoagulants to treat venous thromboembolism (VTE).

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians and other health care professionals in their decisions about the use of anticoagulants in the management of VTE. These guidelines assume the choice of anticoagulant has already been made.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 25 recommendations and 2 good practice statements to optimize management of patients receiving anticoagulants.

CONCLUSIONS

Strong recommendations included using patient self-management of international normalized ratio (INR) with home point-of-care INR monitoring for vitamin K antagonist therapy and against using periprocedural low-molecular-weight heparin (LMWH) bridging therapy. Conditional recommendations included basing treatment dosing of LMWH on actual body weight, not using anti-factor Xa monitoring to guide LMWH dosing, using specialized anticoagulation management services, and resuming anticoagulation after episodes of life-threatening bleeding.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Evidence-Based Best Practices for Outpatient Management of Warfarin

Many best practices have been described for organizing a clinic to manage warfarin. Although these practices may have face validity, they may not be based on empirical analysis. Here, we describe our decade-long effort to apply the Structure-Process-Outcome model of quality measurement as a basis for measuring and improving outpatient warfarin management in the Veterans Health Administration. The purpose of the article is to raise awareness of this body of work with pharmacists who could potentially incorporate the findings of this work into their own practice settings. We conclude with concrete suggestions for immediate implementation in clinical settings.

Development of Quality Indicators to Assess Oral Anticoagulant Management in Community Pharmacies for Patients with Atrial Fibrillation

BACKGROUND

Few studies have evaluated the quality of oral anticoagulant management by community pharmacists. There is no complete set of quality indicators available for this purpose.

OBJECTIVE

To develop a set of specific quality indicators to assess oral anticoagulant management by community pharmacists for patients with atrial fibrillation (AF).

METHODS

Quality indicators were developed in 3 phases. In phase 1, potential quality indicators were generated based on clinical guidelines and a literature review. In phase 2, a modified RAND appropriateness method involving 2 rounds was implemented with 9 experts, who judged the appropriateness of quality indicators generated in phase 1 based on the extent to which they were accurate, based on evidence, relevant, representative of best practices, and measurable in community pharmacies. Phase 3 consisted of a feasibility assessment in 5 community pharmacies on 2 patients each.

RESULTS

The final set included 38 quality indicators grouped into 6 categories: documentation (n = 29), risk assessment (n = 3), clinical control (n = 1), clinical follow-up (n = 15), choice of therapy (n = 11), and interaction management (n = 8). The quality indicators referred to process of care (n = 34), clinical outcomes (n = 2), or structure of care (n = 2). There were 24 quality indicators related to vitamin K antagonists (VKAs), and 17 were related to direct oral anticoagulants (DOACs). To assess quality indicators, a questionnaire was developed for completion by community pharmacists for each patient, which included 17 questions about VKA patients and 12 questions about DOAC patients.

CONCLUSIONS

A first set of quality indicators is now available to assess the quality of oral anticoagulant management by community pharmacists for patients with AF.

DISCLOSURES

This research was supported by the Réseau Québécois de recherche sur le médicament (RQRM); the Blueprint for Pharmacy in collaboration with Pfizer Canada; and the Cercle du Doyen of the Faculty of Pharmacy, University of Montreal. The study sponsors were not involved in the study design, data collection, data interpretation, the writing of the article, or the decision to submit the report for publication. Chartrand received a scholarship from the Fonds de Recherche du Québec en Santé (FRQ-S), the Réseau Québécois de recherche sur l'usage des médicaments with Pfizer, and the Faculty of Pharmacy, University of Montreal. Guénette holds a Junior-1 Clinician Researcher Award from the FRQ-S in partnership with the Société québécoise d'hypertension artérielle. Williamson holds a Junior-1 Career Award from the FRQ-S. Côté reported being a medical speaker for Bayer, Boehringer Ingelheim Canada, and Pfizer Canada. The other authors reported no conflicts of interest. Study concept and design were contributed by Lalonde, Chartrand, and Martin. Chartrand, Martin, and Lalonde collected the data, along with Brouillette, Côté, Huot, Landry, Martineau, Perreault, Williamson, and White-Guay. Data interpretation was performed by Chartrand, Gagnon, and Lalonde, along with Guénette and Martin. The manuscript was primarily written by Chartrand, along with Guénette and Lalonde, and revised by Chartrand, Guénette, and Lalonde, along with the other authors. A portion of this study's results was presented at the 4th RQRM Annual Meeting on September 22-23, 2014, in Orford, Quebec, Canada, in the form of an abstract, which was published in the Journal of Population Therapeutics and Clinical Pharmacology, 2014;21(2):e312.

Dedicated warfarin care programme results in superior warfarin control in Queensland, Australia

BACKGROUND

Warfarin is used to prevent stroke in patients with atrial fibrillation (AF). Ongoing monitoring of International normalised ratio (INR) and time in therapeutic range (TTR) commonly used to assess the quality of warfarin management are required. Anticoagulant clinics have demonstrated improved TTRs, particularly in countries with poorer control in primary care settings. Reported TTR in Australia has been relatively high; so, it is unknown if benefit would be seen from dedicated warfarin clinics in Australia. The aim of this study was to compare the level of warfarin control in patients managed by their general practitioner (GP) and a warfarin care programme (WCP) by Sullivan Nicolaides Pathology.

METHOD

Retrospective data were collected for AF patients enrolled in the warfarin care programme at WCP, and included patients with INR tests available while managed by their GP. INR tests were used to calculate TTR and frequency of testing for the time managed by GP and WCP, with mean data used for analysis and comparison.

RESULTS

The eligible 200 warfarin patients had a TTR of 69% with GP management and 82% with WCP management (<.0001). Significant differences were also found between GP and WCP management in the percentage of tests in range, total number of tests and frequency of testing. WCP had a reduced time to repeat test at extremes of INR results.

CONCLUSION

Australian warfarin control was good when managed by either GP or WCP, but WCP management increased TTR by 13%. Dedicated warfarin programmes can improve warfarin control and optimise therapy for patients.

Effect of increased time in the therapeutic range on atrial fibrillation outcomes within a centralized anticoagulation service

BACKGROUND

Clinical pharmacy anticoagulation services have improved the quality of anticoagulant therapy and are associated with lower rates of bleeding and thromboembolism compared to usual care. Several studies have found that higher time-in-therapeutic range (TTR) during warfarin therapy is associated with better warfarin outcomes. However, whether increasing TTR over time within an established anticoagulation service is associated with further reduction in bleeding and thromboembolic outcomes is unknown.

METHODS

This was a retrospective cohort study of patients with atrial fibrillation conducted at an integrated healthcare delivery system with a centralized, pharmacist-managed anticoagulation service. Clinical outcomes (clinically-relevant bleeding, ischemic stroke or systemic embolism, and all-cause mortality) and TTR were compared between two distinct time periods: 1/1/2006 through 12/31/2007 (control group) and 1/1/2012 through 12/31/2013 (observation group) with regression modeling to adjustment for potential confounders.

RESULTS

There were 3641 and 4764 patients in the control and observation groups, respectively. The mean age was 74.3 years and 54.4% of the cohort was female. Mean TTR was higher in the observation group (70.5% vs. 63.4%, p < 0.001). The composite outcome of clinically-relevant bleeding, thromboembolism and all-cause mortality occurred in 4.6% and 3.6% of the control and observation groups, respectively (adjusted odds ratio = 0.69; 95% confidence interval 0.54-0.87). Individual rates of stroke/systemic embolism and all-cause mortality were each lower in the observation group (both p < 0.05) while clinically-relevant bleeding was not significantly different (p = 0.256).

CONCLUSION

Increased TTR within a clinical pharmacy anticoagulation management service was associated with a lower risk of the composite outcomes of bleeding, thromboembolism and death in a large atrial fibrillation population receiving warfarin.

Warfarin monitoring in nursing homes assessed by case histories. Do recommendations and electronic alerts affect judgements?

PURPOSE

Older adults treated with warfarin are prone to complications, and high-quality monitoring is essential. The aim of this case history based study was to assess the quality of warfarin monitoring in a routine situation, and in a situation with an antibiotic-warfarin interaction, before and after receiving an electronic alert.

MATERIALS AND METHODS

In April 2014, a national web-based survey with two case histories was distributed among Norwegian nursing home physicians and general practitioners working part-time in nursing homes. Case A represented a patient on stable warfarin treatment, but with a substantial INR increase within the therapeutic interval. Case B represented a more challenging patient with trimethoprim sulfamethoxazole (TMS) treatment due to pyelonephritis. In both cases, the physicians were asked to state the next warfarin dose and the INR recall interval. In case B, the physicians could change their suggestions after receiving an electronic alert on the TMS-warfarin interaction.

RESULTS

Three hundred and ninety eight physicians in 292 nursing homes responded. Suggested INR recall intervals and warfarin doses varied substantially in both cases. In case A, 61% gave acceptable answers according to published recommendations, while only 9% did so for case B. Regarding the TMS-warfarin interaction in case history B, the electronic alert increased the percentage of respondents correctly suggesting a dose reduction from 29% to 53%. Having an INR instrument in the nursing home was associated with shortened INR recall times.

CONCLUSIONS

Practical advice on handling of warfarin treatment and drug interactions is needed. Electronic alerts as presented in electronic medical records seem insufficient to change practice. Availability of INR instruments may be important regarding recall time.

Forming and activating an internal facilitation group for successful implementation: A qualitative study

BACKGROUND

This study focuses on an implementation facilitation strategy to improve the delivery of anticoagulation care within pharmacy-run clinics across 8 Veterans Health Administration (VA) medical centers. Other studies have explored various models of implementation facilitation, including external facilitation (EF), internal facilitation (IF), and blended facilitation (BF) combining both approaches. This study focuses on the use of an internal facilitation team of anticoagulation coordinators representing 8 VA anticoagulation clinics to enhance the implementation process. This study examines how the team became instrumental in the successful implementation of evidence-based practice change.

METHODS

Semi-structured interviews were conducted annually over 4 years with representatives from each site, the internal facilitators (site champions), at 8 VA hospitals (47 interviews). Additionally, five external facilitators, experts in quality improvement and anticoagulation care who guided the implementation, were interviewed. Analysis drew on a deductive approach based on the Promoting Action on Research Implementation in Health Services (PARIHS) model and emergent thematic analysis to identify factors related to effectiveness of the internal facilitation team.

RESULTS

Key findings are that the following factors enhanced successful uptake of the anticoagulation initiative: 1) Regular participation by the site champion in the internal facilitation team; 2) Champion strongly committed to being an agent of change; and 3) Champion received greater support from their supervisors. The first and second factors are interrelated, as internal facilitators who actively and regularly participated in the internal facilitation team often became truly committed to the improvement project. Both factors relate to the third, as supervisor support not only facilitated changes in practice, but also facilitated regular team attendance and stronger participation.

CONCLUSIONS

Our study adds to implementation science by detailing how internal facilitators learn their skills over time, and how a group of internal facilitators can help each other succeed. These findings can guide those who wish to incorporate internal facilitation teams as an implementation strategy, and demonstrate how sites can build capacity for implementation efforts.

SYNOPSIS

This study focuses on an implementation facilitation strategy to improve the delivery of anticoagulation care within pharmacy-run clinics across 8 Veterans Health Administration medical centers. Internal facilitators (IFs) guided by and supported by an external facilitators (EF), successfully implemented the clinical innovation. This study examines how the IF group became instrumental in the successful implementation of evidence-based practice change.

Results of a Regional Effort to Improve Warfarin Management

BACKGROUND

Improved anticoagulation control with warfarin reduces adverse events and represents a target for quality improvement. No previous study has described an effort to improve anticoagulation control across a health system.

OBJECTIVE

To describe the results of an effort to improve anticoagulation control in the New England region of the Veterans Health Administration (VA).

METHODS

Our intervention encompassed 8 VA sites managing warfarin for more than 5000 patients in New England (Veterans Integrated Service Network 1 [VISN 1]). We provided sites with a system to measure processes of care, along with targeted audit and feedback. We focused on processes of care associated with site-level anticoagulation control, including prompt follow-up after out-of-range international normalized ratio (INR) values, minimizing loss to follow-up, and use of guideline-concordant INR target ranges. We used a difference-in-differences (DID) model to examine changes in anticoagulation control, measured as percentage time in therapeutic range (TTR), as well as process measures and compared VISN 1 sites with 116 VA sites located outside VISN 1.

RESULTS

VISN 1 sites improved on TTR, our main indicator of quality, from 66.4% to 69.2%, whereas sites outside VISN 1 improved from 65.9% to 66.4% (DID 2.3%, P < 0.001). Improvement in TTR correlated strongly with the extent of improvement on process-of-care measures, which varied widely across VISN 1 sites.

CONCLUSIONS

A regional quality improvement initiative, using performance measurement with audit and feedback, improved TTR by 2.3% more than control sites, which is a clinically important difference. Improving relevant processes of care can improve outcomes for patients receiving warfarin.

Guidance for the practical management of warfarin therapy in the treatment of venous thromboembolism

Venous thromboembolism (VTE) is a serious and often fatal medical condition with an increasing incidence. The treatment of VTE is undergoing tremendous changes with the introduction of the new direct oral anticoagulants and clinicians need to understand new treatment paradigms. This article, initiated by the Anticoagulation Forum, provides clinical guidance based on existing guidelines and consensus expert opinion where guidelines are lacking. Well-managed warfarin therapy remains an important anticoagulant option and it is hoped that anticoagulation providers will find the guidance contained in this article increases their ability to achieve optimal outcomes for their patients with VTE Pivotal practical questions pertaining to this topic were developed by consensus of the authors and were derived from evidence-based consensus statements whenever possible. The medical literature was reviewed and summarized using guidance statements that reflect the consensus opinion(s) of all authors and the endorsement of the Anticoagulation Forum’s Board of Directors. In an effort to provide practical and implementable information about VTE and its treatment, guidance statements pertaining to choosing good candidates for warfarin therapy, warfarin initiation, optimizing warfarin control, invasive procedure management, excessive anticoagulation, subtherapeutic anticoagulation, drug interactions, switching between anticoagulants, and care transitions are provided.

A Practical Guide to Using the Positive Deviance Method in Health Services Research

OBJECTIVE

To provide practical tips for health services researchers considering the use of positive deviance (PD) methods to help explain variations in quality of care or other meaningful parameters.

DATA SOURCES

Published literature and personal experience.

STUDY DESIGN

Narrative review.

PRINCIPAL FINDINGS

This review includes a discussion of possible applications of PD to health services research, some methodological choices applicable to PD, and some brief tips regarding publishing the results and incorporating them into future interventions.

CONCLUSIONS

It is hoped that this article will help health services researchers to use this valuable research method more effectively, especially those who have not done so before.

The impact of frequency of patient self-testing of prothrombin time on time in target range within VA Cooperative Study #481: The Home INR Study (THINRS), a randomized, controlled trial

Anticoagulation (AC) is effective in reducing thromboembolic events for individuals with atrial fibrillation (AF) or mechanical heart valve (MHV), but maintaining patients in target range for international normalized ratio (INR) can be difficult. Evidence suggests increasing INR testing frequency can improve time in target range (TTR), but this can be impractical with in-clinic testing. The objective of this study was to test the hypothesis that more frequent patient-self testing (PST) via home monitoring increases TTR. This planned substudy was conducted as part of The Home INR Study, a randomized controlled trial of in-clinic INR testing every 4 weeks versus PST at three different intervals. The setting for this study was 6 VA centers across the United States. 1,029 candidates with AF or MHV were trained and tested for competency using ProTime INR meters; 787 patients were deemed competent and, after second consent, randomized across four arms: high quality AC management (HQACM) in a dedicated clinic, with venous INR testing once every 4 weeks; and telephone monitored PST once every 4 weeks; weekly; and twice weekly. The primary endpoint was TTR at 1-year follow-up. The secondary endpoints were: major bleed, stroke and death, and quality of life. Results showed that TTR increased as testing frequency increased (59.9 ± 16.7 %, 63.3 ± 14.3 %, and 66.8 ± 13.2 % [mean ± SD] for the groups that underwent PST every 4 weeks, weekly and twice weekly, respectively). The proportion of poorly managed patients (i.e., TTR <50 %) was significantly lower for groups that underwent PST versus HQACM, and the proportion decreased as testing frequency increased. Patients and their care providers were unblinded given the nature of PST and HQACM. In conclusion, more frequent PST improved TTR and reduced the proportion of poorly managed patients.

Percent Time in Range with Warfarin as a Performance Measure: How Long a Sampling Frame Is Needed?

BACKGROUND

Warfarin is received by millions of patients in the United States and elsewhere and will remain the most commonly used anticoagulant for the foreseeable future. Percent time in therapeutic range (TTR) with warfarin is increasingly used as a performance measure. However, stakeholders have expressed concern that TTR lags behind changes in performance. Work in a larger study focused on the impact of shortening the conventional measurement period for TTR.

METHODS

Some 124 sites within the Department of Veterans Affairs (VA) were examined during a seven-year period (fiscal years [FYs] 2008-2014 (April 1, 2007-September 30, 2014). The duration of time segments (2, 3, 4, 6 months) used to calculate TTR were varied, and these four durations were compared in terms of the number of patients retained per site, mean and median site TTR, and site performance rankings.

RESULTS

Data were obtained on 295,237 unique patients who received anticoagulation. As the calculation window shortened, patients with better control (that is, higher TTR) were selectively excluded from the measurement because their laboratory values were more widely spaced. Site mean TTR was highest when the most patients were included (6 months: 950 patients; TTR 65.2%) and lowest when the fewest patients were included (2 months: 567 patients; TTR 60.0%). However, the 3-, 4-, and 6-month segments achieved similar results, each of which included more than 800 patients per site, with mean TTR across a narrow range (64.9%-65.2%). Site rankings were less highly correlated between the 2-month period and longer periods (r = 0.7- 0.8) but were otherwise 0.95 or higher, with a nearly perfect correlation (0.985) between the 4- and 6-month periods.

CONCLUSIONS

When TTR is used to measure site-level performance, comparable results can be achieved using a 4- or a 6-month measurement period. On the basis of these results, the use of a 4-month period for future measurement efforts is recommended.

Center-Related Determinants of VKA Anticoagulation Quality: A Prospective, Multicenter Evaluation

Background

Center-specific TTR (c-TTR) is a measure reporting the mean patient TTR within an anticoagulation clinic describing the quality of anticoagulant monitoring offered by that clinic. c-TTR has a considerable between-center variation, but its determinants are poorly understood.

Objectives

We aimed at evaluating which clinical, procedural or laboratory factors could be associated with c-TTR variability in a multicenter, observational cross-sectional study over a five-year period.

Patients/Methods

Data from 832,204 individual patients followed for VKA therapy in 292 Centers affiliated with the Italian Federation of Anticoagulation Clinics (FCSA) were analyzed. c-TTR was computed based on the TTR of patients followed at each Center, and a mixed linear regression model was used for a predefined set of explanatory variables.

Results

The Center next-visit interval ratio (the mean number of days after a visit with an INR outside the therapeutic range, divided by the days after a visit with an INR within the therapeutic range), the Center mean patient INR and the Center laboratory performance at EQA proficiency testing were the only variables that were independently associated with c-TTR (β-coefficients -17.32, 9.67, and -0.11, respectively; r² = 0.635).

Conclusions

These findings suggest that c-TTR associates with proactive strategies aimed at keeping patients very close to their target INR with a prompt re-evaluation of those patients with under- or over-therapeutic INR.

The interplay of contextual elements in implementation: an ethnographic case study

Background

Contextual elements have significant impact on uptake of health care innovations. While existing conceptual frameworks in implementation science suggest contextual elements interact with each other, little research has described how this might look in practice. To bridge this gap, this study identifies the interconnected patterns among contextual elements that influence uptake of an anticoagulation clinic improvement initiative.

Methods

We completed 51 semi-structured interviews and ethnographic observations across five case study sites involved in an evidence-based practice (EBP) quality improvement initiative. We analyzed data in NVivo 10 using an a priori approach based on the Promoting Action on Research Implementation in Health Services (PARIHS) model and an emergent thematic analysis.

Results

Key contextual elements, such as leadership, teamwork, and communication, interacted with each other in contributing to site-level uptake of the EBP, often yielding results that could not be predicted by looking at just one of these elements alone. Sites with context conducive to change in these areas predictably had high uptake, while sites with uniformly weak contextual elements had low uptake. Most sites presented a mixed picture, with contextual elements being strongly supportive of change in some areas and weak or moderate in others. In some cases, we found that sites with strong context in at least one area only needed to have adequate context in other areas to yield high uptake. At other sites, weak context in just one area had the potential to contribute to low uptake, despite countervailing strengths. Even a site with positive views of EBPs could not succeed when context was weak.

Conclusion

Interrelationships among different contextual elements can act as barriers to uptake at some sites and as facilitators at others. Accounting for interconnections among elements enables PARIHS to more fully describe the determinants of successful implementation as they operate in real-world settings.

Venous thromboembolism among HIV-positive patients and anticoagulation clinic outcomes integrated within the HIV primary care setting

The purpose of this study was to explore factors associated with venous thromboembolism (VTE) among a cohort of HIV-infected patients and to describe early outcomes of warfarin anticoagulation therapy treated in a pharmacist-based anticoagulation clinic (ACC). A nested case-control study was conducted using the University of Alabama at Birmingham 1917 HIV Clinic Cohort. Conditional logistic regression was used to estimate factors associated with VTE. Among HIV-infected VTE cases, ACC-managed patients were compared to primary care provider (PCP)-managed patients to determine Time within Therapeutic INR Range (TTR). CD4 < 200 cells/µl (OR = 4.50; 95% CI = 1.52, 13.37; p = 0.007) and prior surgical procedures (13.20; 1.56; 111.4; p = 0.018) demonstrated positive associations with VTE, whereas longer HIV duration demonstrated a negative association (0.87; 0.78, 0.98; p = 0.019). TTR was 56.2% among ACC-managed patients compared to 30.5% of PCP-managed patients (p = 0.174). Overall, prior surgical procedures and low CD4 count were associated with an increased risk of VTE among HIV-infected patients. Despite small sample size, patients managed in ACC tend to achieve greater proportion of TTR compared to those managed by PCPs, suggesting that this model of therapy may provide additional benefits to HIV-infected patients.

Introduction of point-of-care testing in Japanese outpatient clinics is associated with improvement in time in therapeutic range in anticoagulant-treated patients

BACKGROUND

Warfarin reduces the risk of stroke in patients with atrial fibrillation, but requires a moderate-to-high time in therapeutic range (TTR). We hypothesized that point-of-care (POC) testing for prothrombin time-internationalized normalized ratio (PT-INR) could improve the TTR in patients receiving warfarin.

METHODS AND RESULTS

Eight outpatient clinics that introduced POC testing for PT-INR participated in this study. We identified 148 consecutive patients who received warfarin for at least 12 months before and after the introduction of POC testing. We compared the TTR before and after the introduction of POC testing for each patient. TTR after the introduction of POC testing was significantly higher than that beforehand (51.9%±33.0% vs. 69.3%±26.3%; P<0.0001). The improvement in TTR was statistically significant in patients who had low TTR (<70%) before the introduction of POC testing. After the introduction of POC, the time spent above the target INR showed no significant change (3.7%±10.6% vs. 3.3%±6.3%, P=0.7322), while that spent below the target INR improved significantly (44.4%±34.4% vs. 27.4%±27.6%, P<0.0001).

CONCLUSIONS

The introduction of POC testing was associated with an improvement in TTR, mainly through a reduction in the time spent below the target INR.

Vitamin K antagonists and time in the therapeutic range: implications, challenges, and strategies for improvement

Oral vitamin K antagonists are highly efficacious in the prevention and treatment of thromboembolic disease. Optimal use of these agents in clinical practice is challenged by their narrow therapeutic window. The proportion of time spent in the International Normalized Ratio (INR) range of 2.0-3.0 [time in the therapeutic range (TTR)] has been closely associated with adverse outcomes, i.e., stroke, hemorrhage, mortality. Although TTR is a validated marker, it has several limitations. TTR does not capture short-term risks associated with highly variable periods or periods characterized by extreme deviations in INR. Because TTR measurement is limited to consecutive periods of warfarin exposure, it does not inform the risks associated with gap periods of 56 days or greater as these time intervals are excluded from end-point rate calculations. Because individuals with gaps in monitoring represent a different patient population than those without gaps, e.g., less adherent, more acutely ill, more frequent transitions in health status, TTR analyses are likely most valid and informative for individuals with uninterrupted monitoring of the INR. Duration of warfarin therapy and patient-specific factors have also been shown to influence TTR. Younger age, female sex, lower income, black race, frequent hospitalizations, polypharmacy, active cancer, decompensated heart failure, substance abuse, psychiatric disorders, dementia, and chronic liver disease have all been associated with lower TTR. Targeted strategies to improve TTR are urgently needed.

Impact of global geographic region on time in therapeutic range on warfarin anticoagulant therapy: data from the ROCKET AF clinical trial

Background

Vitamin K antagonist (VKA) therapy remains the most common method of stroke prevention in patients with atrial fibrillation. Time in therapeutic range (TTR) is a widely cited measure of the quality of VKA therapy. We sought to identify factors associated with TTR in a large, international clinical trial.

Methods and Results

TTR (international normalized ratio [INR] 2.0 to 3.0) was determined using standard linear interpolation in patients randomized to warfarin in the ROCKET AF trial. Factors associated with TTR at the individual patient level (i‐TTR) were determined via multivariable linear regression. Among 6983 patients taking warfarin, recruited from 45 countries grouped into 7 regions, the mean i‐TTR was 55.2% (SD 21.3%) and the median i‐TTR was 57.9% (interquartile range 43.0% to 70.6%). The mean time with INR <2 was 29.1% and the mean time with an INR >3 was 15.7%. While multiple clinical features were associated with i‐TTR, dominant determinants were previous warfarin use (mean i‐TTR of 61.1% for warfarin‐experienced versus 47.4% in VKA‐naïve patients) and geographic region where patients were managed (mean i‐TTR varied from 64.1% to 35.9%). These effects persisted in multivariable analysis. Regions with the lowest i‐TTRs had INR distributions shifted toward lower INR values and had longer inter‐INR test intervals.

Conclusions

Independent of patient clinical features, the regional location of medical care is a dominant determinant of variation in i‐TTR in global studies of warfarin. Regional differences in mean i‐TTR are heavily influenced by subtherapeutic INR values and are associated with reduced frequency of INR testing.

Clinical Trial Registration

URL: ClinicalTrials.gov. Unique identifier: NCT00403767.

Most Important Outcomes Research Papers on Anticoagulation for Cardiovascular Disease

The following are highlights from the new series, Circulation: Cardiovascular Quality and Outcomes Topic Review. This series will summarize the most important manuscripts, as selected by the Editor, that have been published in the Circulation portfolio. The objective of this new series is to provide our readership with a timely, comprehensive selection of important papers that are relevant to the quality and outcomes, and general cardiology audience. The studies included in this article represent the most significant research in the area of anticoagulation for cardiovascular disease.

Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

High-quality anticoagulation management is required to keep these narrow therapeutic index medications as effective and safe as possible. This article focuses on the common important management questions for which, at a minimum, low-quality published evidence is available to guide best practices.

METHODS

The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

Most practical clinical questions regarding the management of anticoagulation, both oral and parenteral, have not been adequately addressed by randomized trials. We found sufficient evidence for summaries of recommendations for 23 questions, of which only two are strong rather than weak recommendations. Strong recommendations include targeting an international normalized ratio of 2.0 to 3.0 for patients on vitamin K antagonist therapy (Grade 1B) and not routinely using pharmacogenetic testing for guiding doses of vitamin K antagonist (Grade 1B). Weak recommendations deal with such issues as loading doses, initiation overlap, monitoring frequency, vitamin K supplementation, patient self-management, weight and renal function adjustment of doses, dosing decision support, drug interactions to avoid, and prevention and management of bleeding complications. We also address anticoagulation management services and intensive patient education.

CONCLUSIONS

We offer guidance for many common anticoagulation-related management problems. Most anticoagulation management questions have not been adequately studied.

INR targets and site-level anticoagulation control: results from the Veterans AffaiRs Study to Improve Anticoagulation (VARIA)

BACKGROUND

Not all clinicians target the same International Normalized Ratio (INR) for patients with a guideline-recommended target range of 2-3. A patient's mean INR value suggests the INR that was actually targeted. We hypothesized that sites would vary by mean INR, and that sites of care with mean values nearest to 2.5 would achieve better anticoagulation control, as measured by per cent time in therapeutic range (TTR).

OBJECTIVES

To examine variations among sites in mean INR and the relationship with anticoagulation control in an integrated system of care.

PATIENTS/METHODS

We studied 103,897 patients receiving oral anticoagulation with an expected INR target between 2 and 3 at 100 Veterans Health Administration (VA) sites from 1 October 2006 to 30 September 2008. Key site-level variables were: proportion near 2.5 (that is, percentage of patients with mean INR between 2.3 and 2.7) and mean risk-adjusted TTR.

RESULTS

Site mean INR ranged from 2.22 to 2.89; proportion near 2.5, from 30 to 64%. Sites' proportions of patients near 2.5, below 2.3 and above 2.7 were consistent from year to year. A 10 percentage point increase in the proportion near 2.5 predicted a 3.8 percentage point increase in risk-adjusted TTR (P < 0.001).

CONCLUSIONS

Proportion of patients with mean INR near 2.5 is a site-level 'signature' of care and an implicit measure of targeted INR. This proportion varies by site and is strongly associated with site-level TTR. Our study suggests that sites wishing to improve TTR, and thereby improve patient outcomes, should avoid the explicit or implicit pursuit of non-standard INR targets.

Quality improvement in an anticoagulation clinic: development of a new treatment protocol

We sought to improve patient outcomes and efficiency in our anticoagulation clinic through development of a new protocol for managing heart valve patients with subtherapeutic international normalized ratio (INR) tests. The new protocol standardized use of 1 anticoagulation agent while warfarin was retitrated, timelines for INR retesting, and target INR levels depending on the type of valve implanted. The new protocol provided significant improvements in patient care; however, outcomes for clinic operating efficiency were mixed.

[Stereophotography of the ocular fundus. 2. Observation method]

Traditional anticoagulant agents such as vitamin K antagonists (VKAs), unfractionated heparin (UFH), low molecular weight heparins (LMWHs) and fondaparinux have been widely used in the prevention and treatment of thromboembolic diseases. However, these agents are associated with limitations, such as the need for regular coagulation monitoring (VKAs and UFH) or a parenteral route of administration (UFH, LMWHs and fondaparinux).

Several non-VKA oral anticoagulants (NOACs) are now widely used in the prevention and treatment of thromboembolic diseases and in stroke prevention in non-valvular atrial fibrillation. Unlike VKAs, NOACs exhibit predictable pharmacokinetics and pharmacodynamics. They are therefore usually given at fixed doses without routine coagulation monitoring. However, in certain patient populations or special clinical circumstances, measurement of drug exposure may be useful, such as in suspected overdose, in patients experiencing a hemorrhagic or thromboembolic event during the treatment’s period, in those with acute renal failure, in patients who require urgent surgery or in case of an invasive procedure. This article aims at providing guidance on laboratory testing of classic anticoagulants and NOACs.