title: Longitudinal treatment patterns with ADP receptor inhibitors after myocardial infarction: Insights from the Canadian Observational AntiPlatelet sTudy.
abstract: BACKGROUND
  After myocardial infarction (MI) treated with percutaneous coronary intervention (PCI), guidelines recommend dual antiplatelet therapy (DAPT) with aspirin and an ADP receptor inhibitor (ADPri) for at least 1year. However, whether real-world Canadian practice patterns reflect this recommendation is unknown.
  
  
  METHODS
  We studied 2175 MI patients treated with PCI and discharged from 26 Canadian hospitals between 12/2011 and 05/2013 in the Canadian Observational Antiplatelet sTudy (COAPT). Hierarchical Cox proportional hazard regression modeling was used to determine baseline demographic and clinical factors associated with duration of ADPri therapy post-discharge.
  
  
  RESULTS
  At index-hospitalization discharge, 1597 (73%) patients were treated with clopidogrel, 220 (10%) with prasugrel, and 358 (17%) with ticagrelor. ADPri was discontinued prior to 1year in 474 (21.8%) patients; discontinuation rates were lowest for patients discharged on prasugrel (17.7%), compared with clopidogrel (22.5%) or ticagrelor (21.0%), (log rank test, p=0.03). In addition to regional variability, factors associated with shorter ADPri duration included older age, low body weight, Killip III/IV heart failure, atrial fibrillation, ticagrelor on discharge, and bare metal stent use, while longer ADPri duration was associated with history of prior MI.
  
  
  CONCLUSIONS
  One in five PCI-treated MI patients did not complete Canadian guideline-recommended 1-year course of ADPri treatment. Premature ADPri discontinuation was most strongly associated with factors that increase the risk of bleeding. Further study is required to assess the clinical implications of premature ADPri discontinuation on patient outcomes.
authors.affiliation: Terrence Donnelly Heart Centre, St Michael's Hospital, University of Toronto, Toronto, ON, Canada. Electronic address: bagaia@smh.ca.
authors.forename: Akshay
authors.initials: A
authors.lastname: Bagai
authors.affiliation: Duke Clinical Research Institute, Durham, NC, USA.
authors.forename: Tracy Y
authors.initials: TY
authors.lastname: Wang
authors.affiliation: Terrence Donnelly Heart Centre, St Michael's Hospital, University of Toronto, Toronto, ON, Canada; Canadian Heart Research Centre, Toronto, ON, Canada.
authors.forename: Shaun G
authors.initials: SG
authors.lastname: Goodman
authors.affiliation: Eli Lilly Canada Inc., Toronto, ON, Canada.
authors.forename: Harold N
authors.initials: HN
authors.lastname: Fisher
authors.affiliation: Mazankowski Alberta Heart Institute, University of Alberta, Canadian VIGOUR Centre, Edmonton, AB, Canada.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Welsh
authors.affiliation: Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Quebec, QC, Canada.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Dery
authors.affiliation: Eli Lilly and Company, Indianapolis, IN, United States.
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Eli Lilly and Company, Indianapolis, IN, United States.
authors.forename: Yajun E
authors.initials: YE
authors.lastname: Zhu
authors.affiliation: Terrence Donnelly Heart Centre, St Michael's Hospital, University of Toronto, Toronto, ON, Canada.
authors.forename: Asim N
authors.initials: AN
authors.lastname: Cheema
authors.affiliation: Prairie Vascular Research Network, Regina Qu'Appelle Health Region, Regina, SK, Canada.
authors.forename: Payam
authors.initials: P
authors.lastname: Dehghani
authors.affiliation: Rouge Valley Health System, Toronto, ON, Canada.
authors.forename: Saleem A
authors.initials: SA
authors.lastname: Kassam
authors.affiliation: Cardiac Sciences Program, St Boniface General Hospital, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Ducas
authors.affiliation: Royal Alexandra Hospital, Edmonton, AB, Canada.
authors.forename: Neil
authors.initials: N
authors.lastname: Brass
authors.affiliation: St. Mary's General Hospital, Kitchener, ON, Canada.
authors.forename: Hahn Hoe
authors.initials: HH
authors.lastname: Kim
authors.affiliation: Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Anthony
authors.initials: A
authors.lastname: Fung
authors.affiliation: Hôpital du Sacré-Coeur de Montréal, Université de Montréal, QC, Canada.
authors.forename: Erick
authors.initials: E
authors.lastname: Schampaert
authors.affiliation: Dalhousie University, Queen Elizabeth II Health Sciences Centre, Halifax, NS, Canada.
authors.forename: Ata Ur Rehman
authors.initials: AU
authors.lastname: Quraishi
authors.affiliation: Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, ON, Canada.
authors.forename: Shamir R
authors.initials: SR
authors.lastname: Mehta
mesh_terms: D000241:Adenosine / Q000008:administration & dosage / Q000031:analogs & derivatives; D000368:Aged; D002170:Canada; D000077144:Clopidogrel; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000601:surgery; D062645:Percutaneous Coronary Intervention; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D000068799:Prasugrel Hydrochloride / Q000008:administration & dosage; D058919:Purinergic P2 Receptor Antagonists / Q000008:administration & dosage*; D012189:Retrospective Studies; D000077486:Ticagrelor; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives; D016896:Treatment Outcome
chemical_list: D010975:Platelet Aggregation Inhibitors; D058919:Purinergic P2 Receptor Antagonists; D000077144:Clopidogrel; D000068799:Prasugrel Hydrochloride; D000077486:Ticagrelor; D000241:Adenosine; D013988:Ticlopidine
keywords: ADP receptor inhibitors; Myocardial infarction; Percutaneous coronary intervention