title: Using machine-learned bayesian belief networks to predict perioperative risk of clostridium difficile infection following colon surgery.
abstract: BACKGROUND
  Clostridium difficile (C-Diff) infection following colorectal resection is an increasing source of morbidity and mortality.
  
  
  OBJECTIVE
  We sought to determine if machine-learned Bayesian belief networks (ml-BBNs) could preoperatively provide clinicians with postoperative estimates of C-Diff risk.
  
  
  METHODS
  We performed a retrospective modeling of the Nationwide Inpatient Sample (NIS) national registry dataset with independent set validation. The NIS registries for 2005 and 2006 were used for initial model training, and the data from 2007 were used for testing and validation. International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes were used to identify subjects undergoing colon resection and postoperative C-Diff development. The ml-BBNs were trained using a stepwise process. Receiver operating characteristic (ROC) curve analysis was conducted and area under the curve (AUC), positive predictive value (PPV), and negative predictive value (NPV) were calculated.
  
  
  RESULTS
  From over 24 million admissions, 170,363 undergoing colon resection met the inclusion criteria. Overall, 1.7% developed postoperative C-Diff. Using the ml-BBN to estimate C-Diff risk, model AUC is 0.75. Using only known a priori features, AUC is 0.74. The model has two configurations: a high sensitivity and a high specificity configuration. Sensitivity, specificity, PPV, and NPV are 81.0%, 50.1%, 2.6%, and 99.4% for high sensitivity and 55.4%, 81.3%, 3.5%, and 99.1% for high specificity. C-Diff has 4 first-degree associates that influence the probability of C-Diff development: weight loss, tumor metastases, inflammation/infections, and disease severity.
  
  
  CONCLUSIONS
  Machine-learned BBNs can produce robust estimates of postoperative C-Diff infection, allowing clinicians to identify high-risk patients and potentially implement measures to reduce its incidence or morbidity.
authors.affiliation: Madigan Army Medical Center, Department of Surgery, Tacoma, WA, United States. harkersteele@mac.com.
authors.forename: Scott
authors.initials: S
authors.lastname: Steele
authors.forename: Anton
authors.initials: A
authors.lastname: Bilchik
authors.forename: John
authors.initials: J
authors.lastname: Eberhardt
authors.forename: Philip
authors.initials: P
authors.lastname: Kalina
authors.forename: Aviram
authors.initials: A
authors.lastname: Nissan
authors.forename: Eric
authors.initials: E
authors.lastname: Johnson
authors.forename: Itzhak
authors.initials: I
authors.lastname: Avital
authors.forename: Alexander
authors.initials: A
authors.lastname: Stojadinovic
keywords: Bayesian belief network; Clostridium difficile; NIS; colectomy; pseudomembranous colitis