title: Pretransplant prediction of posttransplant survival for liver recipients with benign end-stage liver diseases: a nonlinear model.
abstract: BACKGROUND
  The scarcity of grafts available necessitates a system that considers expected posttransplant survival, in addition to pretransplant mortality as estimated by the MELD. So far, however, conventional linear techniques have failed to achieve sufficient accuracy in posttransplant outcome prediction. In this study, we aim to develop a pretransplant predictive model for liver recipients' survival with benign end-stage liver diseases (BESLD) by a nonlinear method based on pretransplant characteristics, and compare its performance with a BESLD-specific prognostic model (MELD) and a general-illness severity model (the sequential organ failure assessment score, or SOFA score).
  
  
  RESULTS
  With retrospectively collected data on 360 recipients receiving deceased-donor transplantation for BESLD between February 1999 and August 2009 in the west China hospital of Sichuan university, we developed a multi-layer perceptron (MLP) network to predict one-year and two-year survival probability after transplantation. The performances of the MLP, SOFA, and MELD were assessed by measuring both calibration ability and discriminative power, with Hosmer-Lemeshow test and receiver operating characteristic analysis, respectively. By the forward stepwise selection, donor age and BMI; serum concentration of HB, Crea, ALB, TB, ALT, INR, Na(+); presence of pretransplant diabetes; dialysis prior to transplantation, and microbiologically proven sepsis were identified to be the optimal input features. The MLP, employing 18 input neurons and 12 hidden neurons, yielded high predictive accuracy, with c-statistic of 0.91 (P<0.001) in one-year and 0.88 (P<0.001) in two-year prediction. The performances of SOFA and MELD were fairly poor in prognostic assessment, with c-statistics of 0.70 and 0.66, respectively, in one-year prediction, and 0.67 and 0.65 in two-year prediction.
  
  
  CONCLUSIONS
  The posttransplant prognosis is a multidimensional nonlinear problem, and the MLP can achieve significantly high accuracy than SOFA and MELD scores in posttransplant survival prediction. The pattern recognition methodologies like MLP hold promise for solving posttransplant outcome prediction.
authors.affiliation: Liver Transplantation Center, West China Hospital, Sichuan University Medical School, Chengdu, People's Republic of China.
authors.forename: Ming
authors.initials: M
authors.lastname: Zhang
authors.forename: Fei
authors.initials: F
authors.lastname: Yin
authors.forename: Bo
authors.initials: B
authors.lastname: Chen
authors.forename: You Ping
authors.initials: YP
authors.lastname: Li
authors.forename: Lu Nan
authors.initials: LN
authors.lastname: Yan
authors.forename: Tian Fu
authors.initials: TF
authors.lastname: Wen
authors.forename: Bo
authors.initials: B
authors.lastname: Li
mesh_terms: D000328:Adult; D000465:Algorithms; D002138:Calibration; D058625:End Stage Liver Disease / Q000401:mortality / Q000628:therapy*; D005260:Female; D006085:Graft Survival; D006801:Humans; D016031:Liver Transplantation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D017711:Nonlinear Dynamics; D017063:Outcome Assessment, Health Care; D011379:Prognosis; D012372:ROC Curve; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome