title: The increased mortality associated with a weekend emergency admission is due to increased illness severity and altered case-mix.
abstract: BACKGROUND
  A weekend emergency medical admission has been associated with a higher mortality. We have examined all weekend admissions to St James' Hospital, Dublin between 2002 and 2009.
  
  
  METHODS
  We divided admissions by weekday or weekend (Saturday or Sunday) presentation. We utilised a multivariate logistic model, to determine whether a weekend admission was independently predictive of 30 day outcome.
  
  
  RESULTS
  There were 49337 episodes recorded in 25883 patients; 30-day inhospital mortality at the weekend (9.9% vs. 9.0%) had an unadjusted Odds Ratio of 1.11 (95% CI 0.99, 1.23: p=0.057). In the full risk unlike the univariate) model, a weekend admission was not independently predictive (OR 1.05; 95% CI: 0.88, 1.24). The case-mix for a weekend admission differed; with more neurological diagnoses (22.8% vs 20.4% : p = 0.001) and less gastrointestinal disease (18.3% vs 21.1% : p = 0.001). A biochemistry only illness severity score predicted a higher mortality for weekend admissions.
  
  
  CONCLUSIONS
  Patients admitted at the weekend had an approximate 11% increased 30-day in-hospital mortality, compared with a weekday admission. However, admission at the weekend was not independently predictive in a risk model that included Illness Severity (age and biochemical markers) and co-morbidity. Sicker patients, with a worse outcome, are admitted over the weekend; these considerations should inform the allocation of healthcare resources.
authors: Division of Internal Medicine, Trinity Centre for Health Sciences, Ireland.
authors: O
authors: O
authors: Mikulich
authors: E
authors: E
authors: Callaly
authors: K
authors: K
authors: Bennett
authors: D
authors: D
authors: O'Riordan
authors: B
authors: B
authors: Silke
mesh_terms: D000328:Adult; D000368:Aged; D004630:Emergencies / Q000453:epidemiology*; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality / Q000639:trends*; D006801:Humans; D007494:Ireland / Q000453:epidemiology; D007902:Length of Stay / Q000639:trends; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010343:Patient Admission; D012189:Retrospective Studies; D020379:Risk Adjustment / Q000379:methods*; D012720:Severity of Illness Index; D013997:Time Factors