title: Inter-hospital transfers and outcomes of critically ill patients with severe acute kidney injury: a multicenter cohort study.
abstract: BACKGROUND
  Patients with severe acute kidney injury (AKI) who are hospitalized at centers that do not provide renal replacement therapy (RRT) are frequently subjected to inter-hospital transfer for the provision of RRT. It is unclear whether such transfers are associated with worse patient outcomes as compared with the receipt of initial care in a center that provides RRT. This study examined the relationship between inter-hospital transfer and 30-day mortality among critically ill patients with AKI who received RRT.
  
  
  METHODS
  We conducted a retrospective cohort study of all critically ill patients who commenced RRT for AKI at two academic hospitals in Toronto, Canada. The exposure of interest was inter-hospital transfer for the administration of RRT. We evaluated the relationship between transfer status and 30-day mortality (primary outcome) and RRT dependence at 30 days following RRT initiation (secondary outcome), by using multivariate logistic regression with adjustment for patient demographics, clinical factors, biochemical indices, and severity of illness.
  
  
  RESULTS
  Of 370 patients who underwent RRT for AKI, 82 (22.2%) were transferred for this purpose from another hospital. Compared with non-transferred patients who started RRT, transferred patients were younger (61 ± 15 versus 65 ± 15 years, P = 0.03) and had a higher serum creatinine concentration at RRT initiation (474 ± 295 versus 365 ± 169 μmol/L, P = 0.002). Inter-hospital transfer was not associated with mortality (adjusted odds ratio 0.61, 95% confidence interval 0.33 to 1.12) or RRT-dependence (adjusted odds ratio 1.64, 95% confidence interval 0.70 to 3.81) at 30 days.
  
  
  CONCLUSIONS
  Within the limitations of this observational study and the potential for residual confounding, inter-hospital transfer of critically ill patients with AKI was not associated with a higher risk of death or dialysis dependence 30 days after the initiation of acute RRT.
authors.forename: Paul
authors.initials: P
authors.lastname: Kudlow
authors.forename: Karen E A
authors.initials: KE
authors.lastname: Burns
authors.forename: Neill K J
authors.initials: NK
authors.lastname: Adhikari
authors.forename: Benjamin
authors.initials: B
authors.lastname: Bell
authors.forename: David J
authors.initials: DJ
authors.lastname: Klein
authors.forename: Bin
authors.initials: B
authors.lastname: Xie
authors.forename: Jan O
authors.initials: JO
authors.lastname: Friedrich
authors.forename: Ron
authors.initials: R
authors.lastname: Wald
mesh_terms: D000046:Academic Medical Centers; D058186:Acute Kidney Injury / Q000401:mortality* / Q000628:therapy*; D000368:Aged; D002170:Canada; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010360:Patient Transfer; D017582:Renal Replacement Therapy; D012189:Retrospective Studies; D012307:Risk Factors