Five Years Survival of Patients After Liver Transplantation and Its Effective Factors by Neural Network and Cox Poroportional Hazard Regression Models.
BACKGROUND
Transplantation is the only treatment for patients with liver failure. Since the therapy imposes high expenses to the patients and community, identification of effective factors on survival of such patients after transplantation is valuable.


OBJECTIVE
The current study attempted to model the survival of patients (two years old and above) after liver transplantation using neural network and Cox Proportional Hazards (Cox PH) regression models. The event is defined as death due to complications of liver transplantation.


METHODS
In a historical cohort study, the clinical findings of 1168 patients who underwent liver transplant surgery (from March 2008 to march 2013) at Shiraz Namazee Hospital Organ Transplantation Center, Shiraz, Southern Iran, were used. To model the one to five years survival of such patients, Cox PH regression model accompanied by three layers feed forward artificial neural network (ANN) method were applied on data separately and their prediction accuracy was compared using the area under the receiver operating characteristic curve (ROC). Furthermore, Kaplan-Meier method was used to estimate the survival probabilities in different years.


RESULTS
The estimated survival probability of one to five years for the patients were 91%, 89%, 85%, 84%, and 83%, respectively. The areas under the ROC were 86.4% and 80.7% for ANN and Cox PH models, respectively. In addition, the accuracy of prediction rate for ANN and Cox PH methods was equally 92.73%.


CONCLUSIONS
The present study detected more accurate results for ANN method compared to those of Cox PH model to analyze the survival of patients with liver transplantation. Furthermore, the order of effective factors in patients' survival after transplantation was clinically more acceptable. The large dataset with a few missing data was the advantage of this study, the fact which makes the results more reliable.
Department of Biostatistics, Shiraz University of Medical Sciences, Shiraz, IR Iran.
Bahareh
B
Khosravi
Department of Biostatistics, Shiraz University of Medical Sciences, Shiraz, IR Iran ; Colorectal Research Center, Shiraz University of Medical Sciences, Shiraz, IR Iran.
Saeedeh
S
Pourahmad
Department of Organ Transplantation, Ahvaz University of Medical Sciences, Ahvaz, IR Iran.
Amin
A
Bahreini
Department of Organ Transplantation, Shiraz University of Medical Sciences, Shiraz, IR Iran.
Saman
S
Nikeghbalian
Center of Namazee Hospital Organ Transplant, Shiraz, IR Iran.
Goli
G
Mehrdad
Cox Proportional Hazards Model; Liver Transplantation; Neural Network