title: Weekend versus weekday admission and mortality from myocardial infarction.
abstract: BACKGROUND
  Management of acute myocardial infarction requires urgent diagnostic and therapeutic procedures, which may not be uniformly available throughout the week.
  
  
  METHODS
  We examined differences in mortality between patients admitted on weekends and those admitted on weekdays for a first acute myocardial infarction, using the Myocardial Infarction Data Acquisition System. All such admissions in New Jersey from 1987 to 2002 (231,164) were included and grouped in 4-year intervals.
  
  
  RESULTS
  There were no significant differences in demographic characteristics, coexisting conditions, or infarction site between patients admitted on weekends and those admitted on weekdays. However, patients admitted on weekends were less likely to undergo invasive cardiac procedures, especially on the first and second days of hospitalization (P<0.001). In the interval from 1999 to 2002 (59,786 admissions), mortality at 30 days was significantly higher for patients admitted on weekends (12.9% vs. 12.0%, P=0.006). The difference became significant the day after admission (3.3% vs. 2.7%, P<0.001) and persisted at 1 year (1% absolute difference in mortality). The difference in mortality at 30 days remained significant after adjustment for demographic characteristics, coexisting conditions, and site of infarction (hazard ratio, 1.048; 95% confidence interval [CI], 1.022 to 1.076; P<0.001), but it became nonsignificant after additional adjustment for invasive cardiac procedures (hazard ratio, 1.023; 95% CI, 0.997 to 1.049; P=0.09).
  
  
  CONCLUSIONS
  For patients with myocardial infarction, admission on weekends is associated with higher mortality and lower use of invasive cardiac procedures. Our findings suggest that the higher mortality on weekends is mediated in part by the lower rate of invasive procedures, and we speculate that better access to care on weekends could improve the outcome for patients with acute myocardial infarction.
authors.affiliation: Department of Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ 08903-0019, USA. kostiswj@umdnj.edu
authors.forename: William J
authors.initials: WJ
authors.lastname: Kostis
authors.forename: Kitaw
authors.initials: K
authors.lastname: Demissie
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Marcella
authors.forename: Yu-Hsuan
authors.initials: YH
authors.lastname: Shao
authors.forename: Alan C
authors.initials: AC
authors.lastname: Wilson
authors.forename: Abel E
authors.initials: AE
authors.lastname: Moreyra
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000706:statistics & numerical data; D006328:Cardiac Catheterization / Q000706:statistics & numerical data; D001026:Coronary Artery Bypass / Q000706:statistics & numerical data; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007902:Length of Stay; D008297:Male; D009203:Myocardial Infarction / Q000401:mortality* / Q000628:therapy; D010043:Outcome and Process Assessment, Health Care; D010343:Patient Admission; D013997:Time Factors