title: Impact of acute kidney injury exposure period among liver transplantation patients.
abstract: BACKGROUND
  Acute kidney injury is a common complication of liver transplantation. In this single-centre retrospective observational study, we investigated the impact of acute kidney disease on liver recipient survival.
  
  
  METHODS
  The study population consisted of patients who underwent a liver engraftment between January 2002 and November 2006, at a single transplantation centre in São Paulo, Brazil. Acute kidney injury diagnosis and staging were according to the recommendations of the Acute Kidney Injury Network and consisted of scanning the daily serum creatinine levels throughout the hospital stay. Patients requiring renal replacement therapy prior to transplantation, those who developed acute kidney injury before the procedure or those receiving their second liver graft were excluded from the study.
  
  
  RESULTS
  A total of 444 liver transplantations were performed during the study period, and 129 procedures (29%) were excluded. The remaining 315 patients constituted the study population. In 207 procedures, the recipient was male (65%). The mean age of the population was 51 years. Cumulative incidence of acute kidney injury within 48 h, during the first week after transplantation, and throughout the hospital stay was 32, 81 and 93%, respectively. Renal replacement therapy was required within a week after the transplantation in 31 procedures (10%), and another 17 (5%) required replacement therapy after that period. Mean follow-up period was 2.3 years. Time in days from acute kidney injury diagnosis to initiation of replacement therapy or reaching serum creatinine peak was associated with lower overall survival even when adjusted for significant potential confounders (HR 1.03; 95% CI 1.01, 1.05; p=0.002). Overall, patients experiencing acute kidney injury lasting for a week or more before initiation of replacement therapy experienced a threefold increase in risk of death (HR 3.02; 95% CI 2.04, 4.46; p<0.001).
  
  
  CONCLUSIONS
  Acute kidney injury after liver transplantation is remarkably frequent and has a substantial impact on patient survival. Delaying the initiation of renal replacement therapy in such population may increase mortality by more than 20% per day.
authors: Division of Nephrology, Federal University of São Paulo, São Paulo, Brazil.
authors: Roberto Camargo
authors: RC
authors: Narciso
authors: Leonardo Rolim
authors: LR
authors: Ferraz
authors: Sergio
authors: S
authors: Mies
authors: Julio Cesar Martins
authors: JC
authors: Monte
authors: Oscar Fernando Pavão
authors: OF
authors: dos Santos
authors: Miguel Cendoroglo
authors: MC
authors: Neto
authors: Cassio José de Oliveira
authors: CJ
authors: Rodrigues
authors: Marcelo Costa
authors: MC
authors: Batista
authors: Marcelino Souza
authors: MS
authors: Durão
mesh_terms: D058186:Acute Kidney Injury / Q000175:diagnosis / Q000209:etiology* / Q000401:mortality*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016031:Liver Transplantation / Q000009:adverse effects* / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends