title: Pre-transplant kidney function predicts chronic kidney disease after liver transplant: meta-analysis of observational studies.
abstract: BACKGROUND
  Chronic kidney disease is a common problem in long-term survivors after liver transplantation. Several studies to clarify the risk factors for incidence of chronic kidney disease among liver transplant recipients, including preoperative kidney function, have yielded conflicting results.
  
  
  OBJECTIVE
  The aim of this study was to conduct a systematic review of the published medical literature on the impact of pre-transplant kidney function on the occurrence of chronic kidney disease after liver transplantation.
  
  
  METHODS
  Study-specific relative risks were weighted by the inverse of their variance to obtain fixed- and random-effects pooled estimates for incidence of chronic kidney disease across the published studies. The relative risk of chronic kidney disease after liver transplantation according to pre-transplant glomerular filtration rate was regarded as the most reliable outcome end-point.
  
  
  RESULTS
  We identified seven studies (38,036 unique liver transplant recipients). A stratified analysis including only studies provided with glomerular filtration rate at transplant reported that the summary estimate of relative risk and 95% confidence intervals (CIs) for developing chronic renal failure among liver transplant recipients with diminished renal function at transplant was 2.12 (95% CI, 1.01; 4.46) (random-effects model). The p value for study heterogeneity was significant (p = 0.0001). Post-transplant chronic kidney disease shows impact on survival; the summary estimate for the adjusted relative risk of all-cause mortality with chronic kidney disease after liver transplant was 4.35 (95% confidence Intervals, 3.34; 5.66), p = 0.0001 (random-effects model).
  
  
  CONCLUSIONS
  An increased risk of chronic kidney disease frequently exists among liver transplant recipients with reduced renal function at transplant. The occurrence of chronic kidney disease after liver transplantation has a major impact on mortality. Additional studies are needed to understand better the natural history of chronic kidney disease among liver transplant recipients.
authors.affiliation: Division of Nephrology and Dialysis, Maggiore Hospital, IRCCS Foundation, Pad. Croff, Via Commenda 15, 20122, Milan, Italy. fabrizi@policlinico.mi.it
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Fabrizi
authors.forename: Vivek
authors.initials: V
authors.lastname: Dixit
authors.forename: Paul
authors.initials: P
authors.lastname: Martin
authors.forename: Piergiorgio
authors.initials: P
authors.lastname: Messa
mesh_terms: D006801:Humans; D007676:Kidney Failure, Chronic / Q000209:etiology*; D007677:Kidney Function Tests; D016031:Liver Transplantation / Q000009:adverse effects*; D012307:Risk Factors