title: Risk and benefit of dual antiplatelet treatment among non-revascularized myocardial infarction patients in different age groups.
abstract: BACKGROUND
  Dual anti-platelet treatment with clopidogrel and aspirin is indicated for most patients after myocardial infarction. We examined the risk/benefit relationship of dual anti-platelet treatment according to age in a nationwide cohort of 30,532 myocardial infarction patients without revascularization.
  
  
  METHODS
  Patients admitted with first-time myocardial infarction in 2002-2010, not undergoing revascularization, were identified from nationwide Danish registers. Dual anti-platelet treatment use was assessed by claimed prescriptions. Stratified into age groups, risk of bleeding, all-cause mortality and a combined endpoint of cardiovascular death, recurrent myocardial infarction and ischaemic stroke was analysed by Cox proportional-hazard models and tested in a propensity-score matched population.
  
  
  RESULTS
  A total of 21,302 users and 9230 non-users of dual anti-platelet treatment were included (mean age 67.02 (±13.8) years and 64.7% males). Use of dual anti-platelet treatment decreased with age: 80% (<60 years), 76% (60-69 years), 66% (70-79 years) and 52% (>79 years). We found a reduced risk of cardiovascular death, recurrent myocardial infarction and ischaemic stroke in users <60 years (Hazard ratio (HR) =0.69; 95% confidence interval (CI) 0.59-0.80), 60-69 years (HR=0.64; 95% CI 0.56-0.73), 70-79 years (HR=0.80; 95% CI 0.72-0.89) and >79 years (HR=0.92; 95% CI 0.84-1.01, NS). Risk of bleeding increased with dual anti-platelet treatment use in patients aged <60 years (HR=1.63; 95% CI 1.17-2.26), 60-69 years (HR=1.22; 95% CI 0.97-1.59, NS), 70-79 years (HR=1.42; 95% CI 1.17-1.72) and >79 years (HR=1.46; 95% CI 1.22-1.74). Similar tendencies in all four age groups were found in the propensity-matched population.
  
  
  CONCLUSIONS
  Dual anti-platelet treatment use was less likely among elderly patients although similar effects regarding both risk and benefit were found in all age groups. Increased focus on initiating dual anti-platelet treatment in elderly, non-invasively treated myocardial infarction patients is warranted.
authors.affiliation: 1 Department of Cardiology, Copenhagen University Hospital Gentofte, Denmark.
authors.forename: Nikolai
authors.initials: N
authors.lastname: Juul
authors.affiliation: 1 Department of Cardiology, Copenhagen University Hospital Gentofte, Denmark.|2 Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.|3 National Institute of Public Health, University of Southern Denmark, Denmark.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Gislason
authors.affiliation: 1 Department of Cardiology, Copenhagen University Hospital Gentofte, Denmark.
authors.forename: Jonas Bjerring
authors.initials: JB
authors.lastname: Olesen
authors.affiliation: 1 Department of Cardiology, Copenhagen University Hospital Gentofte, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Lamberts
authors.affiliation: 1 Department of Cardiology, Copenhagen University Hospital Gentofte, Denmark.
authors.forename: Morten Lock
authors.initials: ML
authors.lastname: Hansen
authors.affiliation: 1 Department of Cardiology, Copenhagen University Hospital Gentofte, Denmark.
authors.forename: Deniz
authors.initials: D
authors.lastname: Karasoy
authors.affiliation: 1 Department of Cardiology, Copenhagen University Hospital Gentofte, Denmark.
authors.forename: Christine Benn
authors.initials: CB
authors.lastname: Christiansen
authors.affiliation: 1 Department of Cardiology, Copenhagen University Hospital Gentofte, Denmark.|4 Institute of Health, Science and Technology, Aalborg University, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Torp-Pedersen
authors.affiliation: 1 Department of Cardiology, Copenhagen University Hospital Gentofte, Denmark.|5 Department of Cardiology, Copenhagen University Hospital Bispebjerg, Denmark.
authors.forename: Rikke
authors.initials: R
authors.lastname: Sorensen
mesh_terms: D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D001241:Aspirin / Q000627:therapeutic use*; D002423:Cause of Death / Q000639:trends; D000077144:Clopidogrel; D003718:Denmark / Q000453:epidemiology; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D009204:Myocardial Revascularization; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D057216:Propensity Score; D012042:Registries; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin
keywords: Age groups; Aspirin; cardiovascular; clopidogrel; epidemiology; haemorrhage; myocardial infarction