title: Duration of dual antiplatelet treatment with clopidogrel and aspirin in patients with acute coronary syndrome.
abstract: OBJECTIVE
  Dual antiplatelet treatment (DAPT) is a cornerstone in the treatment of acute coronary syndrome (ACS) but the optimal treatment duration is unclear. We aimed to evaluate the effect of DAPT duration with clopidogrel and aspirin on the recurrence of ischaemic events and bleeding in a large, unselected ACS population.
  
  
  RESULTS
  We performed a prospective, observational cohort study of patients in Sweden (n = 56 440) admitted for ACS, with prescribed DAPT and hospitalized between January 2006 and July 2010. Patients were obtained from the SWEDEHEART register and data were merged with registers from the National Board of Health and Welfare. Depending on dispensed clopidogrel tablets, patients were divided into groups based on DAPT duration with clopidogrel and aspirin (3 months: 84-100 clopidogrel tablets (t); >3 months: >100 t; 6 months: 168-200 t; >6 months: >200 t). For the combined primary endpoint, defined as all-cause death, stroke, or re-infarction, only patients with an uneventful first 3-month period (no death, stroke, re-infarction, bleeding, stent thrombosis, or revascularization) were included. The incidence of the primary endpoint was 45 events per 1000 person-years in the >3 months DAPT group compared with 65 events per 1000 person-years in the 3 months DAPT group [adjusted HR 0.84, 95% CI (0.75; 0.95)]. Bleeding was more common in the >3 months treatment group (adjusted HR 1.56, 95% CI (1.18; 2.07), but the number of events was small. For >6 vs. 6 months DAPT, the adjusted HR for the combined endpoint was 0.75 with 95% CI (0.59; 0.95).
  
  
  CONCLUSIONS
  In this contemporary, large real-life ACS population, DAPT for more than 3 months compared with a shorter duration was associated with a lower risk of death, stroke, or re-infarction.
  
  
  BACKGROUND
  Clinicaltrials.gov (NCT01623700).
authors.affiliation: Department of Medical Sciences, Cardiology and Uppsala Clinical Research Center, Uppsala University, Uppsala, Sweden.
authors.forename: Christoph
authors.initials: C
authors.lastname: Varenhorst
authors.forename: Karin
authors.initials: K
authors.lastname: Jensevik
authors.forename: Tomas
authors.initials: T
authors.lastname: Jernberg
authors.forename: Anders
authors.initials: A
authors.lastname: Sundström
authors.forename: Pål
authors.initials: P
authors.lastname: Hasvold
authors.forename: Claes
authors.initials: C
authors.lastname: Held
authors.forename: Bo
authors.initials: B
authors.lastname: Lagerqvist
authors.forename: Stefan
authors.initials: S
authors.lastname: James
mesh_terms: D054058:Acute Coronary Syndrome / Q000188:drug therapy*; D000368:Aged; D001241:Aspirin / Q000627:therapeutic use*; D000077144:Clopidogrel; D004359:Drug Therapy, Combination; D054855:Drug-Eluting Stents; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced; D006760:Hospitalization; D006801:Humans; D008297:Male; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D015607:Stents; D020521:Stroke / Q000209:etiology; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin
keywords: Acute coronary syndrome; Antiplatelet treatment; Aspirin; Clopidogrel; Myocardial infarction