Publications by authors named "Nipun Atreja"

Introduction: Use of oral anticoagulants (OACs) for stroke reduction in atrial fibrillation (AF) varies by race and geography within the United States. We seek to better understand the relationship between OAC underutilization, race, and US geography.

Methods: Patients with AF were selected from the US Centers for Medicare & Medicaid Services claims database from January 1, 2013, to December 31, 2016.

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Warfarin and direct-acting oral anticoagulants (DOACs) are widely prescribed to patients with nonvalvular atrial fibrillation (NVAF) to reduce risk of stroke and systemic embolism (SE). This study aimed to assess the cost-effectiveness of apixaban compared with warfarin, dabigatran and rivaroxaban, for patients with NVAF from a US healthcare payer (Medicare) perspective. A cohort-level Markov model was developed based on a previously published model, for the US setting, factoring in anticipated price decreases due to market entry of generic drugs.

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: Patient outcomes after percutaneous coronary intervention (PCI) have improved over the last 30 years due to better techniques, therapies, and care processes. This study evaluated contemporary predictors of post-PCI major adverse cardiovascular events (MACE) and summarized risk in a parsimonious risk prediction model. : The Cardiovascular Patient-Level Analytical Platform (CLiPPeR) is an observational dataset of baseline variables and longitudinal outcomes from the American College of Cardiology's CathPCI Registry and national claims data.

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Article Synopsis
  • This study investigates the real-world risks of stroke/systemic embolism (SE) and major bleeding (MB) among patients with non-valvular atrial fibrillation (NVAF) who switch from warfarin to direct oral anticoagulants (DOACs) like apixaban, dabigatran, and rivaroxaban.
  • Data was collected from U.S. commercial claims databases between 2012 and 2019, focusing on NVAF patients switching from warfarin to DOACs within 90 days, and employing statistical models to assess risks.
  • Findings suggest that apixaban offers a significantly lower risk of stroke/SE and MB compared to dabigatran, while having a similar
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Article Synopsis
  • Real-world research on how direct oral anticoagulants affect patients with Non-Valvular Atrial Fibrillation (NVAF) is limited, prompting a study to compare risks of stroke/systemic embolism (SE) and major bleeding (MB) among patients switching or continuing medications.
  • The study analyzed data from over 230,000 NVAF patients who started on apixaban or rivaroxaban between 2013 and 2021, comparing outcomes for those who switched to the other drug versus those who continued their original therapy.
  • Results indicated that switching from apixaban to rivaroxaban increased risks for both stroke/SE and MB, while switching from rivaroxaban to apixaban presented similar
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Several observational studies have compared apixaban with rivaroxaban in patients with non-valvular atrial fibrillation (NVAF), but these analyses may be confounded by unmeasured characteristics. This study used provider prescribing preference (PPP) as an instrumental variable (IV) to assess the association between prescriber choice of rivaroxaban vs. apixaban and the study outcomes of stroke/systemic embolism (SE), major bleeding, and death in a retrospective cohort of NVAF patients in the US.

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Objectives: To investigate the journey to oral anticoagulant (OAC) access following formulary-related rejection of apixaban (Eliquis) and evaluate characteristics associated with failure to achieve OAC access among patients with atrial fibrillation (AF).

Study Design: Retrospective study using the Optum Market Clarity Data from January 2016 through February 2020.

Methods: Patients had at least 1 claim rejection for apixaban due to prior authorization (PA), formulary exclusion (FE), or quantity limit (QL) and at least 1 AF diagnosis on or before the rejected claim.

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Objective: To assess potential impacts of formulary tier increases of apixaban-an efficacious oral anticoagulant (OAC) for preventing stroke in patients with atrial fibrillation (AF)-on patients' prescription drug plan (PDP) switching and OAC treatment patterns.

Methods: Nationwide claims data for Medicare beneficiaries with Parts A, B, and D (100% sample) were used to assess apixaban-treated AF patients who faced a formulary tier increase for apixaban in 2017 by their Part D PDP. Patients' out-of-pocket (OOP) costs for apixaban were described, along with PDP switching and OAC treatment patterns.

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Background: Nonadherence to oral anticoagulants (OACs) is a challenge to stroke risk reduction in patients with nonvalvular atrial fibrillation (NVAF). Data on primary medication nonadherence (PMN) in NVAF are lacking.

Objectives: Our aim was to assess the rates and predictors of PMN among NVAF patients who were newly prescribed an OAC.

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Introduction: In the USA, there is a steady rise of atrial fibrillation due to the aging population with increased morbidity. This study evaluated the risk of stroke/systemic embolism (S/SE) and major bleeding (MB) among elderly patients with non-valvular atrial fibrillation (NVAF) and multimorbidity prescribed direct oral anticoagulants (DOACs).

Methods: Using the CMS Medicare database, a retrospective observational study of adult patients with NVAF and multimorbidity who initiated apixaban, dabigatran, or rivaroxaban from January 1, 2012 to December 31, 2017 was conducted.

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Article Synopsis
  • Oral anticoagulants (OACs) are used to reduce stroke and systemic embolism risks in patients with non-valvular atrial fibrillation but may increase major bleeding risks; this study examined the time patients remain event-free on different OACs.
  • The analysis included 466,991 patients who began treatment with warfarin, apixaban, dabigatran, or rivaroxaban, measuring the delay to stroke/systemic embolism and major bleeding events over a 12-month period using data from multiple sources.
  • Results showed that apixaban and dabigatran significantly increased event-free time for both strokes/systemic embolisms and major bleeding compared to warfarin, while rivarox
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In recent years, US payers have increased usage of formulary exclusions as a means to help manage costs. Earlier this year, one of the largest pharmacy benefit managers in the country added Eliquis (apixaban), the most widely used anticoagulant, to its list of excluded medicines from its formulary, raising concerns by physicians and patients. In this commentary, we examine the potential impacts of formulary exclusion of a drug like apixaban-a treatment for patients with atrial fibrillation and venous thromboembolism to help prevent stroke and clotting events and which has been demonstrated to have a strong efficacy and safety profile.

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Introduction: There are a paucity of real-world data examining effectiveness and safety of non-vitamin K antagonist oral anticoagulants (NOACs) and warfarin in nonvalvular atrial fibrillation (NVAF) patients with prior bleeding.

Methods: This retrospective analysis included data from 5 insurance claims databases and included NVAF patients prescribed OACs with prior bleeding. One-to-one propensity score matching was conducted between NOACs and warfarin and between NOACs in each database.

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Introduction: Prescribing patterns and suboptimal adherence present methodological challenges for real-world head-to-head comparisons of ticagrelor and clopidogrel in intent-to-treat studies. The aim of this study was to compare ticagrelor and clopidogrel in an on-treatment population.

Methods: This retrospective cohort study used the Optum™ Clinformatics™ database to identify patients with acute coronary syndrome (ACS) discharged on ticagrelor or clopidogrel between January 1, 2012 and September 30, 2019.

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Heart failure (HF) is common in patients presenting with acute myocardial infarction (MI), but incidence and predictors of new onset HF after hospitalization for MI are less well characterized. We evaluated patients hospitalized for acute MI without preceding or concurrent HF in the National Cardiovascular Data Registry (NCDR) CathPCI and Chest Pain-MI registries linked with claims data between April 2010 and March 2017. Cumulative incidence and independent predictors of HF after discharge were determined, and a simplified risk score was developed to predict incident HF following MI.

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Background: Limited real-world data are available on outcomes following non-cardioembolic minor ischemic stroke (IS) or high-risk transient ischemic attack (TIA), particularly in the United States (US). We examined outcomes and Medicare payments following any severity IS or TIA as well as the subgroup with minor IS or high-risk TIA.

Methods: Medicare beneficiaries >65 years were identified using US nationwide Get with the Guidelines (GWTG)-Stroke Registry linked to Medicare claims data.

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Innovative value strategies for reimbursement of medications include value-based agreements (VBAs) between payers and pharmaceutical manufacturers, which have the potential to improve affordability and patient access to therapy, as well as lead to a reduction in downstream health events and associated medical costs. VBAs link payment for a medication to its performance in real-world clinical practice measured against prespecified outcomes that are aligned to existing evidence. Given its high prevalence, economic burden, and impact on mortality, cardiovascular disease (namely, coronary heart disease) represents an opportunity for VBAs to contribute to improved health outcomes and patient experiences while reducing or containing total medical costs.

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Background: Cost is frequently cited as a barrier to optimal medication use, but the extent to which copayment assistance interventions are used when available, and their impact on evidence-based medication persistence and major adverse cardiovascular events is unknown.

Methods And Results: The ARTEMIS trial (Affordability and Real-World Antiplatelet Treatment Effectiveness After Myocardial Infarction Study) randomized 301 hospitals to usual care versus the ability to provide patients with vouchers that offset copayment costs when filling P2Y inhibitors in the 1 year post-myocardial infarction. In the intervention group, we used multivariable logistic regression to identify patient and medication cost characteristics associated with voucher use.

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Objective: Opioid use disorder (OUD) can be managed with medication assisted therapy (MAT) (methadone [MET], buprenorphine [BUP], or extended-release naltrexone [XR-NTX]) or counseling alone (non-pharmacological therapy [NPT]). The objective of this study was to evaluate healthcare resource utilization and costs associated with XR-NTX compared with alternative treatments for opioid dependence.

Methods: Adults with a diagnosis of opioid dependence who initiated treatment with XR-NTX, BUP, MET, or NPT between January 1, 2011 and December 31, 2014 were identified in the Truven Health MarketScan Commercial administrative claims database.

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