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Dive into the research topics where Keith Friend is active.

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Featured researches published by Keith Friend.


Thrombosis and Haemostasis | 2017

Effectiveness and safety of apixaban versus warfarin in non-valvular atrial fibrillation patients in "real-world" clinical practice: a propensity-matched analysis of 76,940 patients

Xiaoyan Li; Steve Deitelzweig; Allison Keshishian; Melissa Hamilton; Ruslan Horblyuk; Kiran Gupta; Xuemei Luo; Jack Mardekian; Keith Friend; Anagha Nadkarni; Xianying Pan; Gregory Y.H. Lip

Summary The ARISTOTLE trial showed a risk reduction of stroke/systemic embolism (SE) and major bleeding in non-valvular atrial fibrillation (NVAF) patients treated with apixaban compared to warfarin. This retrospective study used four large US claims databases (MarketScan, PharMetrics, Optum, and Humana) of NVAF patients newly initiating apixaban or warfarin from January 1, 2013 to September 30, 2015. After 1:1 warfarin-apixaban propensity score matching (PSM) within each database, the resulting patient records were pooled. Kaplan-Meier curves and Cox proportional hazards models were used to estimate the cumulative incidence and hazard ratios (HRs) of stroke/SE and major bleeding (identified using the first listed diagnosis of inpatient claims) within one year of therapy initiation. The study included a total of 76,940 (38,470 warfarin and 38,470 apixaban) patients. Among the 38,470 matched pairs, 14,563 were from MarketScan, 7,683 were from PharMetrics, 7,894 were from Optum, and 8,330 were from Humana. Baseline characteristics were balanced between the two cohorts with a mean (standard deviation [SD]) age of 71 (12) years and a mean (SD) CHA 2 DS 2 -VASc score of 3.2 (1.7). Apixaban initiators had a significantly lower risk of stroke/SE (HR: 0.67, 95 % CI: 0.59–0.76) and major bleeding (HR: 0.60, 95 % CI: 0.54–0.65) than warfarin initiators. Different types of stroke/SE and major bleeding – including ischaemic stroke, haemorrhagic stroke, SE, intracranial haemorrhage, gastrointestinal bleeding, and other major bleeding – were all significantly lower for apixaban compared to warfarin treatment. Subgroup analyses (apixaban dosage, age strata, CHA 2 DS 2 -VASc or HAS-BLED score strata, or dataset source) all show consistently lower risks of stroke/SE and major bleeding associated with apixaban as compared to warfarin treatment. This is the largest “real-world” study on apixaban effectiveness and safety to date, showing that apixaban initiation was associated with significant risk reductions in stroke/SE and major bleeding compared to warfarin initiation after PSM. These benefits were consistent across various high-risk subgroups and both the standard-and low-dose apixaban dose regimens. Note: The review process for this manuscript was fully handled by Christian Weber, Editor in Chief. Supplementary Material to this article is available online at www.thrombosis-online.com .


Current Medical Research and Opinion | 2018

Outcomes associated with warfarin time in therapeutic range among US veterans with nonvalvular atrial fibrillation.

Shuqian Liu; Xiaoyan Li; Qian Shi; Melissa Hamilton; Keith Friend; Yingnan Zhao; Ruslan Horblyuk; Shalini Hede; Lizheng Shi

Abstract Background: Poor quality of warfarin control (time in therapeutic range [TTR] < 65%) can lead to increased risk of adverse events. The objective of this study was to examine the overall quality of international normalized ratio (INR) control and the association of TTR with clinical outcomes including stroke, major bleeding, and all-cause mortality among US warfarin users. Methods and results: This retrospective observational cohort study utilized the US Veterans Affairs electronic medical records database (VA EMR). Patients with NVAF who newly initiated warfarin from 1 January 2005 to 31 December 2015 were grouped into two cohorts based on TTR <65% or ≥65%. TTR was computed from INR test results. Clinical outcomes assessed were stroke/systemic embolism (SE), hemorrhagic stroke, ischemic stroke, and major bleeding, defined based on hospitalization with those conditions as primary diagnosis, as well as all-cause mortality. Patients were followed from warfarin initiation to the first occurrence of an outcome or censoring. Propensity score weighted time-varying Cox regression was used to evaluate the risk of the clinical events. A total of 127,385 NVAF patients with mean TTR of 51% were included. TTR <65% was observed in 65% of patients. Mean CHA2DS2-VASC score (SD) was 2.9 (1.5) in the low TTR cohort and 2.7 (1.4) in the high TTR cohort. Patients with TTR <65% had a higher risk for any stroke/SE (HR: 1.57; 95% CI: 1.41–1.75), major bleeding (HR: 2.78; 95% CI: 2.55–3.03) and all-cause mortality (HR: 1.73; 95% CI: 1.67–1.79). Conclusions: The observed quality of warfarin control in VA EMR suggests room for improvement given the association with elevated risk of adverse clinical outcomes.


The American Journal of Medicine | 2018

Effectiveness and Safety of Anticoagulants in Adults with Non-valvular Atrial Fibrillation and Concomitant Coronary/Peripheral Artery Disease

Renato D. Lopes; Jan Steffel; Manuela Di Fusco; Allison Keshishian; Xuemei Luo; Xiaoyan Li; Cristina Masseria; Melissa Hamilton; Keith Friend; Kiran Gupta; Jack Mardekian; Xianying Pan; O Baser; W. Schuyler Jones

BACKGROUND Direct oral anticoagulants (DOAC) are at least non-inferior to warfarin in efficacy and safety among patients with nonvalvular atrial fibrillation. Limited evidence is available regarding outcomes for nonvalvular atrial fibrillation patients with coronary/peripheral artery disease. METHODS Non-valvular atrial fibrillation patients aged ≥65 years diagnosed with coronary/peripheral artery disease in the US Medicare population, newly initiating DOACs (apixaban, rivaroxaban, dabigatran) or warfarin were selected from January 1, 2013 to September 30, 2015. Propensity score matching was used to compare DOACs vs warfarin. Cox proportional hazards models were used to estimate the risk of stroke/systemic embolism, major bleeding, and composite of stroke/myocardial infarction/all-cause mortality. RESULTS There were 15,527 apixaban-warfarin, 6,962 dabigatran-warfarin, and 25,903 rivaroxaban-warfarin-matched pairs, with a mean follow-up of 5-6 months. Compared with warfarin, apixaban was associated with lower rates of stroke/systemic embolism (hazard ratio [HR] 0.48; 95% confidence interval [CI], 0.37-0.62), major bleeding (HR 0.66; 95% CI, 0.58-0.75), and stroke/myocardial infarction/all-cause mortality (HR 0.63; 95% CI, 0.58-0.69); dabigatran and rivaroxaban were associated with lower rates of stroke/myocardial infarction/all-cause mortality (HR 0.79; 95% CI, 0.70-0.90 and HR 0.87; 95% CI, 0.81-0.92, respectively). Rivaroxaban was associated with a lower rate of stroke/systemic embolism (HR 0.72; 95% CI, 0.60-0.89) and a higher rate of major bleeding (HR 1.14; 95% CI, 1.05-1.23) vs warfarin. CONCLUSIONS All DOACs were associated with lower stroke/myocardial infarction/all-cause mortality rates compared with warfarin; differences were observed in rates of stroke/systemic embolism and major bleeding. Findings from this observational analysis provide important insights about oral anticoagulation therapy among non-valvular atrial fibrillation patients with coronary/peripheral artery disease and may help physicians in the decision-making process when treating this high-risk group of patients.


PLOS ONE | 2018

Apixaban 5 and 2.5 mg twice-daily versus warfarin for stroke prevention in nonvalvular atrial fibrillation patients: Comparative effectiveness and safety evaluated using a propensity-score-matched approach

Xiaoyan Li; Allison Keshishian; Melissa Hamilton; Ruslan Horblyuk; Kiran Gupta; Xuemei Luo; Jack Mardekian; Keith Friend; Anagha Nadkarni; Xianying Pan; Gregory Y.H. Lip; Steve Deitelzweig

Prior real-world studies have shown that apixaban is associated with a reduced risk of stroke/systemic embolism (stroke/SE) and major bleeding versus warfarin. However, few studies evaluated the effectiveness and safety of apixaban according to its dosage, and most studies contained limited numbers of patients prescribed 2.5 mg twice-daily (BID) apixaban. Using pooled data from 4 American claims database sources, baseline characteristics and outcomes for patients prescribed 5 mg BID and 2.5 mg BID apixaban versus warfarin were compared. After 1:1 propensity-score matching, 31,827 5 mg BID apixaban-matched warfarin patients and 6600 2.5 mg BID apixaban-matched warfarin patients were identified. Patients prescribed 2.5 mg BID apixaban were older, had clinically more severe comorbidities, and were more likely to have a history of stroke and bleeding compared with 5 mg BID apixaban patients. Compared with warfarin, 5 mg BID apixaban was associated with a lower risk of stroke/SE (hazard ratio [HR]: 0.70, 95% confidence interval [CI]: 0.60–0.81) and major bleeding (HR: 0.59, 95% CI: 0.53–0.66). Compared with warfarin, 2.5 mg BID apixaban was also associated with a lower risk of stroke/SE (HR: 0.63, 95% CI: 0.49–0.81) and major bleeding (HR: 0.59, 95% CI: 0.49–0.71). In this real-world study, both apixaban doses were assessed in 2 patient groups differing in age and clinical characteristics. Each apixaban dose was associated with a lower risk of stroke/SE and major bleeding compared with warfarin in the distinct population for which it is being prescribed in United States clinical practice. Trial registration: Clinicaltrials.Gov Identifier: NCT03087487.


Journal of the American College of Cardiology | 2018

COST-EFFECTIVENESS OF EXTENDED AND ONE-TIME SCREENING FOR ATRIAL FIBRILLATION VERSUS NO SCREENING IN THE UNITED STATES

Gail D. Wygant; Mustafa Oguz; Tereza Lanitis; Robert Leipold; Keith Friend; Soeren Mattke; Daniel E. Singer; Andreas Nikolaou; Patrick Hlavacek; Shawn X. Li

Atrial fibrillation (AF) is a common arrhythmia, contributing to ≥15% of strokes in the United States (US). Its often asymptomatic nature makes finding cases challenging, and 24.6% of AF cases remain undiagnosed. Research has focused on screening for AF to prevent stroke via timely intervention.


Journal of the American College of Cardiology | 2018

COMPARISON OF EFFECTIVENESS, SAFETY, AND THE NET CLINICAL OUTCOME BETWEEN DIFFERENT DIRECT ORAL ANTICOAGULANTS IN 162,707 NON-VALVULAR ATRIAL FIBRILLATION PATIENTS TREATED IN US CLINICAL PRACTICE

Steve Deitelzweig; Allison Keshishian; Xiaoyan Li; Melissa Hamilton; Cristina Masseria; Kiran Gupta; Xuemei Luo; Jack Mardekian; Keith Friend; Anagha Nadkarni; Xianying Pan; Onur Baser; Gregory Y.H. Lip


European Heart Journal | 2018

P2568Comparisons of clinical and economic outcomes between non-VKA oral anticoagulants and warfarin among non-valvular atrial fibrillation patients: the ARISTOPHANES study

G. Y. H. Lip; A. Keshishian; Xiaoyan Li; Melissa Hamilton; Cristina Masseria; A Dhamane; Xuemei Luo; Jack Mardekian; Keith Friend; Anagha Nadkarni; Xianying Pan; O Baser; S. Deitelzweig


European Heart Journal | 2018

P2903Comparative effectiveness and safety between non-VKA oral anticoagulants in non-valvular atrial fibrillation patients: a dose subgroup analysis of the ARISTOPHANES study

G. Y. H. Lip; A. Keshishian; Xiaoyan Li; Melissa Hamilton; Cristina Masseria; A Dhamane; Xuemei Luo; Jack Mardekian; Keith Friend; Anagha Nadkarni; Xianying Pan; O Baser; S. Deitelzweig


European Heart Journal | 2018

P979Comparison of effectiveness, safety, and healthcare costs in non-valvular atrial fibrillation patients with heart failure prescribed direct oral anticoagulants

A Amin; A Bassalobre Garcia; Xiaoyan Li; A Dhamane; Xuemei Luo; M Di Fusco; Anagha Nadkarni; Keith Friend; L Rosenblatt; Jack Mardekian; Xianying Pan; O Baser; Allison Keshishian


European Heart Journal | 2018

P4713Evaluation of the risk and determinants of 30-day outcomes following acute heart failure hospitalization using electronic health records

E Nkhoma; P Kessler; Keith Friend; R Wang; L Burns; Maria Borentain; S Singhal; M Desouza

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Allison Keshishian

New York City College of Technology

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