title: Algorithm to determine the outcome of patients with acute liver failure: a data-mining analysis using decision trees.
abstract: BACKGROUND
  We established algorithms to predict the prognosis of acute liver failure (ALF) patients through a data-mining analysis, in order to improve the indication criteria for liver transplantation.
  
  
  METHODS
  The subjects were 1,022 ALF patients seen between 1998 and 2007 and enrolled in a nationwide survey. Patients older than 65 years, and those who had undergone liver transplantation and received blood products before the onset of hepatic encephalopathy were excluded. Two data sets were used: patients seen between 1998 and 2003 (n=698), whose data were used for the formation of the algorithm, and those seen between 2004 and 2007 (n=324), whose data were used for the validation of the algorithm. Data on a total of 73 items, at the onset of encephalopathy and 5 days later, were collected from 371 of the 698 patients seen between 1998 and 2003, and their outcome was analyzed to establish decision trees. The obtained algorithm was validated using the data of 160 of the 324 patients seen between 2004 and 2007.
  
  
  RESULTS
  The outcome of the patients at the onset of encephalopathy was predicted through 5 items, and the patients were classified into 6 categories with mortality rates between 23% and89%. When the prognosis of the patients in the categories with mortality rates greater than 50% was predicted as "death", the accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the algorithm were 79, 78, 81, 83, and 75%, respectively. Similar high values were obtained when the algorithm was employed in the patients for validation. The outcome of the patients 5 days after the onset of encephalopathy was predicted through 7 items, and a similar high accuracy was found for both sets of patients.
  
  
  CONCLUSIONS
  Novel algorithms for predicting the outcome of ALF patients may be useful to determine the indication for liver transplantation.
authors.affiliation: Department of Gastroenterology and Hepatology, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama-Machi, Iruma-gun, Saitama, 350-0495, Japan.
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Nakayama
authors.forename: Makoto
authors.initials: M
authors.lastname: Oketani
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kawamura
authors.forename: Mie
authors.initials: M
authors.lastname: Inao
authors.forename: Sumiko
authors.initials: S
authors.lastname: Nagoshi
authors.forename: Kenji
authors.initials: K
authors.lastname: Fujiwara
authors.forename: Hirohito
authors.initials: H
authors.lastname: Tsubouchi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Mochida
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D057225:Data Mining; D003663:Decision Trees; D005260:Female; D006306:Health Surveys; D006501:Hepatic Encephalopathy / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D006801:Humans; D007564:Japan / Q000453:epidemiology; D017114:Liver Failure, Acute / Q000175:diagnosis* / Q000209:etiology / Q000401:mortality / Q000628:therapy; D016031:Liver Transplantation; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D016896:Treatment Outcome