title: The impact of switching P2Y12 receptor inhibitor therapy during index hospitalization: a systematic review.
abstract: OBJECTIVE
  With the availability of novel P2Y12 receptor inhibitors, patients presenting with acute coronary syndrome (ACS) may receive more than one type of this drug during index hospitalization. We sought to determine the effect of switching from clopidogrel to a novel P2Y12 receptor inhibitor on the occurrence of major adverse cardiovascular events (MACE) and bleeding.
  
  
  METHODS
  We conducted a literature search on SCOPUS for English language entries until 7 March 2015. Out of 188 citations, seven studies encompassing 16,431 patients were selected for analysis of (i) switching to a novel P2Y12 agent (switching group) versus continued clopidogrel or (ii) switching to a novel P2Y12 agent (switching group) versus upfront novel agent initiation during index hospitalization
  
  
  RESULTS
  MACE was significantly lower in the switching group (odds ratio (OR) 0.77, 95 % confidence interval (CI) 0.63-0.96, p = 0.02), whereas bleeding was higher (OR 1.55, 1.29-1.85, p < 0.01) compared with continued clopidogrel. Conversely, MACE was similar with switching to a novel agent and upfront novel therapy initiation (OR 1.01, 95 % CI 0.8-1.29, p = 0.90), but bleeding was higher in the switching group (OR 1.24, 95 % CI 1.03-1.48, p = 0.02).
  
  
  CONCLUSIONS
  The current study suggests that switching to a novel P2Y12 agent in patients with ACS and/or patients undergoing coronary stenting is more efficacious than continuing clopidogrel. In this cohort, switching to a novel agent did not result in worse ischemic outcomes than upfront initiation of novel therapies. However, switching was associated with greater bleeding compared with both continued clopidogrel as well as upfront use of novel P2Y12 agents.
authors.affiliation: Division of Cardiology, University of Ottawa Heart Institute, CAPITAL Research Group, Ottawa, Ontario, Canada. jayachandrasekhar@hotmail.co.uk.|Icahn School of Medicine at Mount Sinai, PO Box 1030, 1 Gustave L Levy place, New York, NY, 10029, USA. jayachandrasekhar@hotmail.co.uk.
authors.forename: Jaya
authors.initials: J
authors.lastname: Chandrasekhar
authors.affiliation: Division of Cardiology, University of Ottawa Heart Institute, CAPITAL Research Group, Ottawa, Ontario, Canada.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Hibbert
authors.affiliation: Division of Cardiology, University of Ottawa Heart Institute, CAPITAL Research Group, Ottawa, Ontario, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Froeschl
authors.affiliation: Division of Cardiology, University of Ottawa Heart Institute, CAPITAL Research Group, Ottawa, Ontario, Canada.
authors.forename: Derek
authors.initials: D
authors.lastname: So
authors.affiliation: Division of Cardiology, University of Ottawa Heart Institute, CAPITAL Research Group, Ottawa, Ontario, Canada.
authors.forename: Roxana
authors.initials: R
authors.lastname: Mehran
authors.affiliation: Division of Cardiology, University of Ottawa Heart Institute, CAPITAL Research Group, Ottawa, Ontario, Canada.
authors.forename: Michel Le
authors.initials: ML
authors.lastname: May
mesh_terms: D002318:Cardiovascular Diseases / Q000188:drug therapy; D000077144:Clopidogrel; D006470:Hemorrhage / Q000139:chemically induced*; D006760:Hospitalization; D006801:Humans; D058921:Purinergic P2Y Receptor Antagonists / Q000009:adverse effects* / Q000627:therapeutic use; D013988:Ticlopidine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D058921:Purinergic P2Y Receptor Antagonists; D000077144:Clopidogrel; D013988:Ticlopidine
keywords: Acute coronary syndrome; P2Y12 receptor blockers; Percutaneous coronary intervention; Switching