title: Readmissions to Intensive Care: A Prospective Multicenter Study in Australia and New Zealand.
abstract: OBJECTIVE
  To determine factors independently associated with readmission to ICU and the independent association of readmission with subsequent mortality.
  
  
  METHODS
  Prospective multicenter observational study.
  
  
  METHODS
  Forty ICUs in Australia and New Zealand.
  
  
  METHODS
  Consecutive adult patients discharged alive from ICU to hospital wards between September 2009 and February 2010.
  
  
  METHODS
  Measurement of hospital mortality.
  
  
  RESULTS
  We studied 10,210 patients and 674 readmissions. The median age was 63 years (interquartile range, 49-74), and 6,224 (61%) were male. The majority of readmissions were unplanned (84.1%) but only deemed preventable in a minority (8.9%) of cases. Time to first readmission was shorter for unplanned than planned readmission (3.2 vs 6.9 d; p < 0.001). Primary diagnosis changed between admission and readmission in the majority of patients (60.2%) irrespective of planned (58.2%) or unplanned (60.6%) status. Using recurrent event analysis incorporating patient frailty, we found no association between readmissions and hospital survival (hazard ratios: first readmission 0.88, second readmission 0.90, third readmission 0.44; p > 0.05). In contrast, age (hazard ratio, 1.03), a medical diagnosis (hazard ratio, 1.43), inotrope use (hazard ratio, 3.47), and treatment limitation order (hazard ratio, 17.8) were all independently associated with outcome.
  
  
  CONCLUSIONS
  In this large prospective study, readmission to ICU was not an independent risk factor for mortality.
authors.affiliation: 1Department of Critical Care Medicine, St Vincent's Hospital (Melbourne), Fitzroy, VIC, Australia. 2Intensive Care Unit, Eastern Health (Box Hill Hospital), Box Hill, VIC, Australia. 3Intensive Care Unit, The Alfred Hospital and ANZIC Research Centre Monash University, Melbourne, VIC, Australia. 4Intensive Care Unit, The Queen Elizabeth Hospital, Woodville South, SA, Australia. 5Australian and New Zealand Research Centre, Monash University, Melbourne, VIC, Australia.
authors.forename: John D
authors.initials: JD
authors.lastname: Santamaria
authors.forename: Graeme J
authors.initials: GJ
authors.lastname: Duke
authors.forename: David V
authors.initials: DV
authors.lastname: Pilcher
authors.forename: D James
authors.initials: DJ
authors.lastname: Cooper
authors.forename: John
authors.initials: J
authors.lastname: Moran
authors.forename: Rinaldo
authors.initials: R
authors.lastname: Bellomo
mesh_terms: D000368:Aged; D001315:Australia / Q000453:epidemiology; D005260:Female; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D010359:Patient Readmission / Q000706:statistics & numerical data*; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors