title: β-blocker therapy and cardiac events among patients with newly diagnosed coronary heart disease.
abstract: BACKGROUND
  The effectiveness of beta-blockers for preventing cardiac events has been questioned for patients who have coronary heart disease (CHD) without a prior myocardial infarction (MI).
  
  
  OBJECTIVE
  The purpose of this study was to assess the association of beta-blockers with outcomes among patients with new-onset CHD.
  
  
  METHODS
  We studied consecutive patients discharged after the first CHD event (acute coronary syndrome or coronary revascularization) between 2000 and 2008 in an integrated healthcare delivery system who did not use beta-blockers in the year before entry. We used time-varying Cox regression models to determine the hazard ratio (HR) associated with beta-blocker treatment and used treatment-by-covariate interaction tests (p(int)) to determine whether the association differed for patients with or without a recent MI.
  
  
  RESULTS
  A total of 26,793 patients were included, 19,843 of whom initiated beta-blocker treatment within 7 days of discharge from their initial CHD event. Over an average of 3.7 years of follow-up, 6,968 patients had an MI or died. Use of beta-blockers was associated with an adjusted HR for mortality of 0.90 (95% confidence limits [CL]: 0.84 to 0.96), and an adjusted HR for death or MI of 0.92 (CL: 0.87 to 0.97). The association between beta-blockers and outcomes differed significantly between patients with and without a recent MI (HR for death: 0.85 vs. 1.02, p(int) = 0.007; and HR for death or MI: 0.87 vs. 1.03, p(int) = 0.005).
  
  
  CONCLUSIONS
  Use of beta-blockers among patients with new-onset CHD was associated with a lower risk of cardiac events only among patients with a recent MI.
authors.affiliation: Department of Cardiology, Gentofte University Hospital, Hellerup, Denmark.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Andersson
authors.affiliation: Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California.
authors.forename: David
authors.initials: D
authors.lastname: Shilane
authors.affiliation: Division of Research, Kaiser Permanente, Oakland, California.
authors.forename: Alan S
authors.initials: AS
authors.lastname: Go
authors.affiliation: Department of Medicine, Stanford University School of Medicine, Stanford, California.
authors.forename: Tara I
authors.initials: TI
authors.lastname: Chang
authors.affiliation: Department of Medicine, University of California, San Francisco, California.
authors.forename: Dhruv
authors.initials: D
authors.lastname: Kazi
authors.affiliation: Division of Research, Kaiser Permanente, Oakland, California.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Solomon
authors.affiliation: Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California.
authors.forename: Derek B
authors.initials: DB
authors.lastname: Boothroyd
authors.affiliation: Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California; Department of Medicine, Stanford University School of Medicine, Stanford, California. Electronic address: hlatky@stanford.edu.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hlatky
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology* / Q000627:therapeutic use*; D000368:Aged; D003327:Coronary Disease / Q000175:diagnosis* / Q000188:drug therapy* / Q000401:mortality; D057286:Electronic Health Records / Q000639:trends; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: D000319:Adrenergic beta-Antagonists
keywords: beta-adrenergic blocking agents; beta-blockers; comparative effectiveness research; outcomes research; treatment effectiveness