title: Chronic disabling disease--impact on outcomes and costs in emergency medical admissions.
abstract: BACKGROUND
  Chronic disabling disease is present in nearly 90% of emergency medical admissions. We have examined its impact on outcomes and costs in one institution, using a database of episodes collected prospectively over 12 years.
  
  
  METHODS
  All emergency admissions (66,933 episodes; 36,271 patients) to St James' Hospital over a 12-year period (2002-13) were evaluated in relation to 30-day in-hospital mortality, length of stay (LOS) and hospital costs. Predictor variables (identified univariately) were entered into a multi-variable logistic regression model to predict 30-day in-hospital mortality. The data were also modelled as count data (absolute LOS, total cost) using zero-truncated Poisson regression.
  
  
  RESULTS
  Acute illness severity was the best independent predictor of mortality; chronic disabling disease was an independent predictor (P < 0.001) for patients with 4+ disabling conditions. Age, adjusted for other predictors, was only independently predictive of mortality for patient 85+ years. Chronic disabling disease was an independent predictor of LOS increasing linearly with incidence rate ratios of 1.35 (95% CI: 1.29, 1.42), 1.59 (95% CI: 1.51, 1.66), 1.73 (95% CI: 1.65, 1.83) and 1.74 (95% CI: 1.65, 1.84) for those with 1, 2, 3 or 4+ disabling conditions, respectively. Age, as a predictor of LOS was strongly correlated with the presence of disabling disease. Chronic disabling disease independently predicted costs non-linearly; those with 2 or more disabling conditions had particularly high total hospital costs.
  
  
  CONCLUSIONS
  Chronic disabling disease is an independent predictor of hospital LOS and costs in unselected emergency admissions; adjusted for illness severity, it is only a mortality predictor for those with multiple disabling conditions.
authors.affiliation: From the Medical Physics and Bioengineering Department, Division of Internal Medicine and Office of the CEO, St. James's Hospital, Dublin 8, Ireland scournane@stjames.ie.
authors.forename: S
authors.initials: S
authors.lastname: Cournane
authors.affiliation: From the Medical Physics and Bioengineering Department, Division of Internal Medicine and Office of the CEO, St. James's Hospital, Dublin 8, Ireland.
authors.forename: D
authors.initials: D
authors.lastname: Byrne
authors.affiliation: From the Medical Physics and Bioengineering Department, Division of Internal Medicine and Office of the CEO, St. James's Hospital, Dublin 8, Ireland.
authors.forename: D
authors.initials: D
authors.lastname: O'Riordan
authors.affiliation: From the Medical Physics and Bioengineering Department, Division of Internal Medicine and Office of the CEO, St. James's Hospital, Dublin 8, Ireland.
authors.forename: B
authors.initials: B
authors.lastname: Fitzgerald
authors.affiliation: From the Medical Physics and Bioengineering Department, Division of Internal Medicine and Office of the CEO, St. James's Hospital, Dublin 8, Ireland.
authors.forename: B
authors.initials: B
authors.lastname: Silke
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D016208:Databases, Factual; D004635:Emergency Medicine; D004636:Emergency Service, Hospital / Q000191:economics*; D005260:Female; D017048:Health Care Costs; D017052:Hospital Mortality; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010343:Patient Admission / Q000191:economics*; D011379:Prognosis; D012720:Severity of Illness Index