Elaine Hylek

Boston University, Boston, Massachusetts, United States

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Publications (57)621.53 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Because of its association with death and disability, stroke is a focus of outcomes in atrial fibrillation (AF) research. International Classification of Disease-Ninth Revision (ICD-9) edition codes are commonly used to identify stroke in research, particularly in large administrative data. We sought to assess the validity of ICD-9 codes in stroke case ascertainment and for AF across 3 institutions. Participating centers included Boston Medical Center (safety net hospital), Geisinger Health System (rural Pennsylvania), and the University of Alabama (academic center in the southeastern stroke belt). ICD-9 codes for ischemic stroke (433-434, 436) and intracranial hemorrhage (430-432) identified 1812 stroke cases with an associated code for AF (427.31) from 2006 to 2010. Cases were vetted through chart review with final adjudication by a stroke neurologist. Review considered 94.2% of ICD-9 identified stroke cases valid with decreased accuracy for concurrent AF diagnosis (82.28%) and stroke attributable to AF (72.8%). Among events with "without infarction" modifiers, 7.2% were valid strokes. ICD-9 stroke code accuracy did not differ by stroke type or site. Stroke code 434 displayed higher accuracy than 433 (94.4% versus 85.2%; P<0.01), and primary stroke codes were more accurate than nonprimary codes (97.2% versus 83.7%; P<0.0001). Using ICD-9 stroke and AF codes to identify patients with stroke plus AF resulted in inaccuracies. Given the expanded financial and policy implications of patient-oriented research, conclusions derived solely from administrative data without validation of outcome events should be interpreted with caution. © 2015 American Heart Association, Inc.
    Circulation Cardiovascular Quality and Outcomes 01/2015; 8(1):8-14. DOI:10.1161/CIRCOUTCOMES.113.000371 · 5.66 Impact Factor
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    ABSTRACT: Amiodarone is an effective medication in preventing atrial fibrillation (AF), but it interferes with the metabolism of warfarin.
    Journal of the American College of Cardiology 10/2014; 64(15):1541-50. DOI:10.1016/j.jacc.2014.07.967 · 15.34 Impact Factor
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    ABSTRACT: Thrombosis is a common pathology underlying ischemic heart disease, ischemic stroke, and venous thromboembolism (VTE). The Global Burden of Disease Study 2010 (GBD 2010) documented that ischemic heart disease and stroke collectively caused one in four deaths worldwide. GBD 2010 did not report data for VTE as a cause of death and disability. We performed a systematic review of the literature on the global disease burden due to VTE in low, middle and high income countries. Studies from Western Europe, North America, Australia, and Southern Latin America (Argentina) yielded consistent results with annual incidences ranging from 0.75 to 2.69 per 1,000 individuals in the population. The incidence increased to between 2 and 7 per 1,000 among those 70 years of age or more. Although the incidence is lower in individuals of Chinese and Korean ethnicity, their disease burden is not low because of population aging. VTE associated with hospitalization was the leading cause of disabilityad justed-life-years (DALYs) lost in low and middle income countries, and second in high income countries, responsible for more DALYs lost than nosocomial pneumonia, catheter-related blood stream infections, and adverse drug events. VTE causes a major burden of disease across low, middle, and high income countries. More detailed data on the global burden of VTE should be obtained to inform policy and resource allocation in health systems, and to evaluate if improved utilization of preventive measures will reduce the burden. (C) 2014 The Authors. Published by Elsevier Ltd.
    Arteriosclerosis Thrombosis and Vascular Biology 10/2014; 134(5). DOI:10.1161/ATVBAHA.114.304488 · 5.53 Impact Factor
  • E M Hylek, D Ko, C L Cove
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    ABSTRACT: Worldwide there is a tremendous need for affordable anticoagulants that do not require monitoring. The advent of the non-warfarin oral anticoagulant drugs represents a major advance for stroke prevention in atrial fibrillation (AF). The objectives of this review are to 1) identify gaps in our current knowledge regarding use of these single target anticoagulant drugs; 2) outline the potential implications of these gaps for clinical practice, and thereby, 3) highlight areas of research to further optimise their use for stroke prevention in AF.
    Thrombosis and Haemostasis 02/2014; 111(5). DOI:10.1160/TH13-12-1032 · 5.76 Impact Factor
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    ABSTRACT: Atrial fibrillation (AF) is an independent risk factor for thromboembolism and stroke. Women with AF are at a higher overall risk for thromboembolic stroke when compared to men with AF. Recent evidence suggests that female sex, after adjusting for stroke risk profile and sex differences in utilisation of anticoagulation, is an independent stroke risk factor in AF. The inclusion of female sex has improved the accuracy of the CHADS2 stroke risk stratification schema (Congestive heart failure, Hypertension, Age 75 years or greater, Diabetes mellitus, and prior Stroke or TIA). The newly revised and validated schema, CHA2DS2-VASc, dichotomises age and incorporates female sex and vascular disease history. The pathophysiological mechanisms to explain this increased risk in women are not well understood. According to Virchow's triad, thrombosis that leads to stroke in AF should arise from three co-existing phenomena: structural abnormalities, blood stasis, and a hypercoagulable state. Herein, we explore the sex differences in the biological processes that lead to thrombus formation as applied to Virchow's Triad. The objective of this review is to describe the potential mechanisms behind the increased risk of stroke in AF associated with female sex.
    Thrombosis and Haemostasis 12/2013; 111(3). DOI:10.1160/TH13-04-0347 · 5.76 Impact Factor
  • Elaine M Hylek
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    ABSTRACT: Warfarin is the mainstay of anticoagulation for patients with mechanical heart valves. However, warfarin has well-known limitations, including interactions with food and drugs and the requirement for lifelong monitoring of the international normalized ratio (INR).(1) Variability of the INR is the strongest independent predictor of reduced survival after mechanical valve replacement.(2) Thus, there is a pressing need for alternatives to warfarin, and the advent of the target-specific oral anticoagulants has been highly anticipated. Eikelboom et al.(3) now report in the Journal the results of a study whose primary aim was to validate a new dosing regimen for dabigatran, as compared . . .
    New England Journal of Medicine 08/2013; 369(13). DOI:10.1056/NEJMe1310399 · 54.42 Impact Factor
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    Christina L Cove, Elaine M Hylek
    Journal of the American Heart Association 08/2013; 2(5):e000136. DOI:10.1161/JAHA.113.000136 · 2.88 Impact Factor
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    ABSTRACT: To identify older adults with comorbidities or poor functional status at high risk of postoperative venous thromboembolism (VTE). Retrospective cohort study. Veterans Affairs Medical Center (VAMC). Older adults who underwent total hip and knee replacement (THR and TKR) from 2002 to 2009. Using multivariate logistic regression, the independent effect of cardiopulmonary comorbidities and diabetes on VTE was analyzed. Functional status expressed in a summary physical component score (PCS) was also analyzed in a subset of individuals in whom information on it was available. There were 23,326 THR and TKR surgeries performed at the VAMC during the study period. Individuals with chronic obstructive pulmonary disease (COPD) had a 25% greater risk of VTE (odds ratio (OR) = 1.25, 95% confidence interval (CI) = 1.06-1.48), whereas those with coronary artery disease, congestive heart failure, and cerebrovascular disease did not have a greater risk of VTE. Individuals with diabetes mellitus had a lower risk of VTE (OR = 0.77, 95% CI = 0.64-0.92). Individuals with low PCS, which were available for 3,169 patients, had a 62% greater risk, although the effect did not reach statistical significance (lowest vs highest quartile OR = 1.62, 95% CI = 0.93-2.80). Individuals with COPD had slightly greater risk of VTE, whereas low functional status had a larger effect that did not reach statistical significance. The constraints of administrative data analysis and sample size available for PCS limit conclusions about the role of these comorbidities and functional status.
    Journal of the American Geriatrics Society 04/2013; 61(4):590-601. DOI:10.1111/jgs.12161 · 4.22 Impact Factor
  • Elaine M Hylek
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    ABSTRACT: 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.
    Journal of Thrombosis and Thrombolysis 03/2013; DOI:10.1007/s11239-013-0900-5 · 2.04 Impact Factor
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    ABSTRACT: Dr. Cohen presents a passionate critique of the 9(th) edition of the American College of Chest Physician Guidelines on Antithrombotic Therapy (AT9), and in particular on its methodologist authors. We believe this attack is misguided and appreciate the opportunity to respond to Dr. Cohen. Dr. Cohen objects to the use of the term patient-important. © 2013 International Society on Thrombosis and Haemostasis.
    Journal of Thrombosis and Haemostasis 02/2013; 11(4). DOI:10.1111/jth.12142 · 5.55 Impact Factor
  • Elaine M Hylek
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    ABSTRACT: Atrial fibrillation (AF) is the most common significant cardiac rhythm disorder, and its prevalence is increasing worldwide. Atrial fibrillation confers a fivefold increased risk of stroke, and these strokes are associated with significant mortality and disability. The vitamin K antagonist, warfarin, has been the mainstay of anticoagulant therapy for patients with AF, reducing the risk of stroke by 65%. Despite its efficacy, warfarin remains underused in clinical practice because of its variable dose response, diet and medication interactions, and need for frequent monitoring. Stroke prevention in AF has entered an exciting therapeutic era with new classes of targeted anticoagulants that avoid the many pitfalls of the vitamin K antagonists. Dabigatran, an oral thrombin inhibitor, and the factor Xa inhibitors, rivaroxaban and apixaban, have demonstrated efficacy for stroke prevention and a reduced risk of intracranial hemorrhage relative to warfarin. Translating the efficacy of clinical trials into effective use of these novel agents in clinical practice will require an understanding of their pharmacokinetic profiles, dose selection, and management in select clinical situations.
    Seminars in Thrombosis and Hemostasis 02/2013; 39(2). DOI:10.1055/s-0033-1334812 · 3.69 Impact Factor
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    ABSTRACT: BACKGROUND AND PURPOSE: Current literature provides mixed evidence on disparities by race/ethnicity and socioeconomic status in discharge outcomes after hospitalization for acute ischemic stroke. Using comprehensive data from 8 states, we sought to compare inpatient mortality and length of stay by race/ethnicity and socioeconomic status. METHODS: We examined all 2007 hospitalizations for acute ischemic stroke in all nonfederal acute care hospitals in Arizona, California, Florida, Maine, New Jersey, New York, Pennsylvania, and Texas. Population was stratified by race/ethnicity (non-Hispanic whites, non-Hispanic blacks, and Hispanics) and socioeconomic status, measured by median income of patient zip code. For each stratum, we estimated risk-adjusted rates of inpatient mortality and longer length of stay (greater than median length of stay). We also compared the hospitals where these subpopulations received care. RESULTS: Hispanic and black patients accounted for 14% and 12% of all ischemic stroke admissions (N=147 780), respectively, and had lower crude inpatient mortality rates (Hispanic=4.5%, blacks=4.4%; all P<0.001) compared with white patients (5.8%). Hispanic and black patients were younger and fewer had any form of atrial fibrillation. Adjusted for patient risk, inpatient mortality was similar by race/ethnicity, but was significantly higher for low-income area patients than that for high-income area patients (odds ratio, 1.08; 95% confidence interval, 1.02-1.15). Risk-adjusted rates of longer length of stay were higher among minority and low-income area populations. CONCLUSIONS: Risk-adjusted inpatient mortality was similar among patients by race/ethnicity but higher among patients from lower income areas. However, this pattern was not evident in sensitivity analyses, including the use of mechanical ventilation as a partial surrogate for stroke severity.
    Stroke 01/2013; 44(2). DOI:10.1161/STROKEAHA.112.669341 · 6.02 Impact Factor
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    ABSTRACT: Comparative effectiveness research (CER) aims to provide decision makers with the evidence needed to evaluate the benefits and harms of alternative clinical management strategies. CER has become a national priority, with considerable new research funding allocated. Cardiovascular disease is a priority area for CER. This workshop report provides an overview of CER methods, with an emphasis on practical clinical trials and observational treatment comparisons. The report also details recommendations to the National Heart, Lung, and Blood Institute for a new framework for evidence development to foster cardiovascular CER, and specific studies to address 8 clinical issues identified by the Institute of Medicine as high priorities for cardiovascular CER.
    Journal of the American College of Cardiology 06/2012; 60(7):569-80. DOI:10.1016/j.jacc.2011.12.057 · 15.34 Impact Factor
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    ABSTRACT: Anticoagulation clinics (ACCs) can improve anticoagulation control and prevent adverse events. However, ACCs vary widely in their performance on anticoagulation control. Our objective was to compare the organization and management of top-performing with that of bottom-performing ACCs. Three high outlier and three low outlier ACCs in the Veterans Health Administration (VA). Site visits with qualitative data collection and analysis. We conducted semi-structured interviews with ACC staff regarding work flow, staffing, organization, and quality assurance efforts. We also observed ACC operations and collected documents, such as the clinic protocol. We used grounded thematic analysis to examine site-level factors associated with high and low outlier status. High outlier sites were characterized by (1) adequate (pharmacist) staffing and effective use of (nonpharmacist) support personnel; (2) innovation to standardize clinical practice around evidence-based guidelines; (3) the presence of a quality champion for the ACC; (4) higher staff qualifications; (5) a climate of ongoing group learning; and (6) internal efforts to measure performance. Although high outliers had all of these features, no low outlier had more than two of them. The top-performing ACCs in the VA system shared six relatively recognizable characteristics. Efforts to improve performance should focus on these domains.
    Health Services Research 02/2012; 47(4):1541-60. DOI:10.1111/j.1475-6773.2011.01377.x · 2.49 Impact Factor
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    ABSTRACT: 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). To examine variations among sites in mean INR and the relationship with anticoagulation control in an integrated system of care. 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. 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). 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.
    Journal of Thrombosis and Haemostasis 01/2012; 10(4):590-5. DOI:10.1111/j.1538-7836.2012.04649.x · 5.55 Impact Factor
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    ABSTRACT: There are exciting new developments in several areas of atrial fibrillation (AF) management that carry the hope of improving outcomes in AF patients. This paper is an executive summary that summarises the proceedings from the 3rd AFNET/EHRA consensus conference on atrial fibrillation, held in Sophia Antipolis from November 7th to 9th 2010, shortly after the release of the new ESC guidelines on AF. The conference was jointly organised by the German Atrial Fibrillation competence NETwork (AFNET) and the European Heart Rhythm Association (EHRA). This executive summary report covers four sections: 1. Risk factors and risk markers for AF, 2. Pathophysiological classification of AF, 3. Relevance of monitored AF duration for AF-related outcomes, and 4. Perspectives and needs for implementing better antithrombotic therapy.
    Thrombosis and Haemostasis 11/2011; 106(6):1012-9. DOI:10.1160/TH11-07-0517 · 5.76 Impact Factor
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    ABSTRACT: In this executive summary of a Consensus Document from the European Heart Rhythm Association, endorsed by the European Society of Cardiology Working Group on Thrombosis, we comprehensively review the published evidence and propose a consensus on bleeding risk assessments in atrial fibrillation (AF) patients. The main aim of the document was to summarise 'best practice' in dealing with bleeding risk in AF patients when approaching antithrombotic therapy, by addressing the epidemiology and size of the problem, and review established bleeding risk factors. We also summarise definitions of bleeding in the published literature. Patient values and preferences balancing the risk of bleeding against thromboembolism as well as the prognostic implications of bleeding are reviewed. We also provide an overview of published bleeding risk stratification and bleeding risk schema. Brief discussion of special situations (e.g. periablation, peri-devices such as implantable cardioverter defibrillators [ICD] or pacemakers, presentation with acute coronary syndromes and/or requiring percutanous coronary interventions/stents and bridging therapy) is made, as well as a discussion of the prevention of bleeds and managing bleeding complications. Finally, this document puts forwards consensus statements that may help to define evidence gaps and assist in everyday clinical practice.
    Thrombosis and Haemostasis 11/2011; 106(6):997-1011. DOI:10.1160/TH11-10-0690 · 5.76 Impact Factor
  • Raffaele De Caterina, Elaine M Hylek
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    ABSTRACT: Prevention of atrial fibrillation-related stroke is an important part of atrial fibrillation management. However, stroke risk is not homogeneous and varies with associated morbidities and risk factors. Risk stratification schemes have been developed that categorize patients' stroke risk into classes based on a combination of risk factors. According to the calculated level of risk, guidelines recommend patients with atrial fibrillation receive antithrombotic therapy either as a vitamin K antagonist or aspirin. Despite recommendations, however, many patients with atrial fibrillation do not receive adequate thromboprophylaxis. We will discuss some of the underlying reasons, in part related to the drawbacks associated with vitamin K antagonists. These highlight the need for new anticoagulants in atrial fibrillation. The novel oral anticoagulants in development may overcome some of the limitations of vitamin K antagonists and address their underuse and safety concerns.
    The American journal of medicine 09/2011; 124(9):793-9. DOI:10.1016/j.amjmed.2011.03.013 · 5.30 Impact Factor
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    ABSTRACT: Prothrombin complex concentrates (PCCs) are recommended as the treatment of choice in warfarin-related coagulopathy. However, the risk of thromboembolic complications associated with their use is not well defined. We performed a meta-analysis to estimate the rate of thromboembolic complications in patients receiving vitamin K antagonists (VKAs) treated with PCCs for bleeding or before urgent surgery. Medline and Embase databases were searched. Two reviewers performed study selection and extracted data independently. Studies providing data on incidence of thromboembolic complications in VKA-treated patients were eligible for the study. Weighted mean proportion of the rate of thromboembolic complications and the mortality rate were calculated. Twenty-seven studies (1,032 patients) were included. Seven studies used 3-factor, and 20 4-factor PCCs. Twelve patients had a thromboembolic complication (weighted mean 1.4%; 95% CI 0.8-2.1), of which two were fatal. The incidence of thromboembolic events was 1.8% (95% CI 1.0-3.0) in patients treated with 4-factor PCCs, and 0.7% (95% CI 0.0-2.4) in patients treated with 3-factor PCCs. Total mortality rate was 10.6% (95% CI 5.9-16.6). In conclusion, our results suggest there is a low but quantifiable risk of thromboembolism in VKA-treated patients receiving PCCs for anticoagulation reversal. These findings should be confirmed in randomised, controlled trials.
    Thrombosis and Haemostasis 07/2011; 106(3):429-38. DOI:10.1160/TH11-01-0052 · 5.76 Impact Factor
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    ABSTRACT: While management of atrial fibrillation (AF) patients is improved by guideline-conform application of anticoagulant therapy, rate control, rhythm control, and therapy of accompanying heart disease, the morbidity and mortality associated with AF remain unacceptably high. This paper describes the proceedings of the 3rd Atrial Fibrillation NETwork (AFNET)/European Heart Rhythm Association (EHRA) consensus conference that convened over 60 scientists and representatives from industry to jointly discuss emerging therapeutic and diagnostic improvements to achieve better management of AF patients. The paper covers four chapters: (i) risk factors and risk markers for AF; (ii) pathophysiological classification of AF; (iii) relevance of monitored AF duration for AF-related outcomes; and (iv) perspectives and needs for implementing better antithrombotic therapy. Relevant published literature for each section is covered, and suggestions for the improvement of management in each area are put forward. Combined, the propositions formulate a perspective to implement comprehensive management in AF.
    Europace 07/2011; 14(1):8-27. DOI:10.1093/europace/eur241 · 3.05 Impact Factor

Publication Stats

6k Citations
621.53 Total Impact Points

Institutions

  • 2008–2015
    • Boston University
      Boston, Massachusetts, United States
  • 2008–2013
    • Boston Medical Center
      Boston, Massachusetts, United States
    • Beverly Hospital, Boston MA
      BVY, Massachusetts, United States
  • 2011–2012
    • University of Massachusetts Boston
      Boston, Massachusetts, United States
  • 2001
    • Harvard University
      Cambridge, Massachusetts, United States
  • 1999–2000
    • Kaiser Permanente
      Oakland, California, United States
  • 1996
    • Massachusetts General Hospital
      • Department of Medicine
      Boston, MA, United States