title: Prognosis and treatment in patients admitted with acute myocardial infarction on weekends and weekdays from 1997 to 2009.
abstract: BACKGROUND
  Less invasive treatment and poorer outcomes have been shown among patients admitted with acute myocardial infarction (AMI) on weekends compared to weekdays.
  
  
  OBJECTIVE
  To investigate the 'weekend-effect' on mortality in patients with AMI.
  
  
  METHODS
  Using nationwide registers we identified 92,164 patients aged 30-90 years who were admitted to a Danish hospital with a first AMI from 1997 to 2009. Patients were stratified according to weekday- or weekend admissions and four time-periods to investigate for temporal changes. All-cause mortality at 2, 7, 30, and 365 days was investigated using proportional hazards Cox regression.
  
  
  RESULTS
  Mortality rates were higher on weekends within seven days of admission in 1997-99 (absolute difference ranging from 0.8 to 1.1%). Weekend-weekday hazard-ratios were 1.13 (1.03-1.23) at day 2 and 1.10 (1.01-1.18) at day 7. There were no significant differences in 2000-09 and estimates suggested an attenuation of the initial 'weekend-effect'. Overall, the use of coronary angiography (34.9% vs. 72.3%) and percutaneous coronary intervention (6.6% vs. 51.0%) within 30 days increased, as did the use of statins (49.9% vs. 80.1%.) and clopidogrel (26.7% vs. 72.7%). The cumulative mortality decreased during the study period from 5.4% to 2.5% at day of admission, from 19.5% to 11.0% at day 30 and from 28.0% to 19.0% at day 365 (all tests for trend p<0.0001).
  
  
  CONCLUSIONS
  No persistent 'weekend-effect' on mortality was present in patients with AMI in 1997-2009. Overall, mortality rates have decreased concomitantly with an increased use of current guideline-recommended invasive and medical therapy.
authors.affiliation: Department of Cardiology, Copenhagen University Hospital Gentofte, Hellerup, Denmark. Electronic address: Kim.Wadt.Hansen@regionh.dk.
authors.forename: Kim Wadt
authors.initials: KW
authors.lastname: Hansen
authors.forename: Anders
authors.initials: A
authors.lastname: Hvelplund
authors.forename: Steen Zabell
authors.initials: SZ
authors.lastname: Abildstrøm
authors.forename: Eva
authors.initials: E
authors.lastname: Prescott
authors.forename: Mette
authors.initials: M
authors.lastname: Madsen
authors.forename: Jan Kyst
authors.initials: JK
authors.lastname: Madsen
authors.forename: Jan Skov
authors.initials: JS
authors.lastname: Jensen
authors.forename: Rikke
authors.initials: R
authors.lastname: Sørensen
authors.forename: Søren
authors.initials: S
authors.lastname: Galatius
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D017052:Hospital Mortality / Q000639:trends*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D010343:Patient Admission / Q000639:trends*; D011379:Prognosis; D012042:Registries; D013997:Time Factors; D016896:Treatment Outcome