title: Exploratory study of the 'weekend effect' for acute medical admissions to public hospitals in Queensland, Australia.
abstract: OBJECTIVE
  To determine whether in-hospital deaths of patients admitted through emergency departments with acute exacerbations of chronic obstructive pulmonary disease (COPD), acute myocardial infarction, intracerebral haemorrhage and acute hip fracture are increased by weekend versus weekday admission (the 'weekend effect').
  
  
  METHODS
  We performed a retrospective analysis of statewide administrative data from public hospitals in Queensland, Australia, during the 2002/2003-2006/2007 financial years. The primary outcome was 30-day in-hospital mortality. The secondary outcome of 2-day in-hospital mortality helped determine whether increased mortality of weekend admissions was closely linked to weekend medical care.
  
  
  RESULTS
  During the study period, there were 30 522 COPD, 17 910 acute myocardial infarction, 4183 acute hip fracture and 1781 intracerebral haemorrhage admissions. There was no significant weekend effect on 30-day in-hospital mortality for COPD (adjusted risk ratio = 0.92, 95% CI: 0.81-1.04, P= 0.222), intracerebral haemorrhage (adjusted risk ratio = 1.01, 95% CI: 0.86-1.16, P= 0.935) or acute hip fracture (adjusted risk ratio = 0.78, 95% CI: 0.54-1.03, P= 0.13). There was a significant weekend effect for acute myocardial infarction (adjusted risk ratio = 1.15, 95% CI: 1.03-1.26, P= 0.007). Two-day in-hospital mortality showed similar results.
  
  
  CONCLUSIONS
  This is the first Australian study on the 'weekend effect' (in a cohort other than neonates), and the first study worldwide to assess specifically the weekend effect among COPD patients. Observed patterns were consistent with overseas research. There was a significant weekend effect for myocardial infarction. Further research is needed to determine whether location (e.g. rural), clinical (e.g. disease severity) and service provision factors (e.g. access to invasive procedures) influence the weekend effect for acute medical conditions in Australia.
authors.affiliation: School of Medicine, The University of Queensland, Brisbane, Queensland, Australia. melissaclarky@gmail.com
authors.forename: M S
authors.initials: MS
authors.lastname: Clarke
authors.forename: R-A
authors.initials: RA
authors.lastname: Wills
authors.forename: R V
authors.initials: RV
authors.lastname: Bowman
authors.forename: P V
authors.initials: PV
authors.lastname: Zimmerman
authors.forename: K M
authors.initials: KM
authors.lastname: Fong
authors.forename: M D
authors.initials: MD
authors.lastname: Coory
authors.forename: I A
authors.initials: IA
authors.lastname: Yang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D016208:Databases, Factual / Q000639:trends; D005260:Female; D017052:Hospital Mortality / Q000639:trends*; D006779:Hospitals, Public / Q000379:methods / Q000592:standards* / Q000639:trends*; D006801:Humans; D008297:Male; D010343:Patient Admission / Q000592:standards* / Q000639:trends*; D011793:Queensland / Q000453:epidemiology; D012189:Retrospective Studies; D013997:Time Factors