title: Comparison of Cox's Regression Model and Parametric Models in Evaluating the Prognostic Factors for Survival after Liver Transplantation in Shiraz during 2000-2012.
abstract: BACKGROUND
  Identification of the prognostic factors for survival in patients with liver transplantation is challengeable. Various methods of survival analysis have provided different, sometimes contradictory, results from the same data.
  
  
  OBJECTIVE
  To compare Cox's regression model with parametric models for determining the independent factors for predicting adults' and pediatrics' survival after liver transplantation.
  
  
  METHODS
  This study was conducted on 183 pediatric patients and 346 adults underwent liver transplantation in Namazi Hospital, Shiraz, southern Iran. The study population included all patients undergoing liver transplantation from 2000 to 2012. The prognostic factors sex, age, Child class, initial diagnosis of the liver disease, PELD/MELD score, and pre-operative laboratory markers were selected for survival analysis.
  
  
  RESULTS
  Among 529 patients, 346 (64.5%) were adult and 183 (34.6%) were pediatric cases. Overall, the lognormal distribution was the best-fitting model for adult and pediatric patients. Age in adults (HR=1.16, p<0.05) and weight (HR=2.68, p<0.01) and Child class B (HR=2.12, p<0.05) in pediatric patients were the most important factors for prediction of survival after liver transplantation. Adult patients younger than the mean age and pediatric patients weighing above the mean and Child class A (compared to those with classes B or C) had better survival.
  
  
  CONCLUSIONS
  Parametric regression model is a good alternative for the Cox's regression model.
authors: Department of Pediatrics, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors: R
authors: R
authors: Adelian
authors: Department of Biostatistics, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors: J
authors: J
authors: Jamali
authors: Department of Biostatistics, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors: N
authors: N
authors: Zare
authors: Department of Biostatistics, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors: S M T
authors: SM
authors: Ayatollahi
authors: Department of Pediatrics, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors: G R
authors: GR
authors: Pooladfar
authors: Department of Biostatistics, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors: N
authors: N
authors: Roustaei
keywords: Adult; Liver transplantation; Pediatrics; Survival analysis