title: Pre-operative nomogram to predict risk of peri-operative mortality following liver resections for malignancy.
abstract: BACKGROUND
  The majority of liver resections for malignancy are performed in older patient with major co-morbidities. There is currently no pre-operative, patient-specific method to determine the likely peri-operative mortality for each individual patient. The aim of this study was to develop a pre-operative nomogram based on the presence of co-morbidities to predict risk of peri-operative mortality following liver resections for malignancy.
  
  
  METHODS
  The Nationwide Inpatient Sample database was queried to identify adult patients that underwent liver resection for malignancy. The pre-operative co-morbidities, identified as predictors were used and a nomogram was created with multivariate regression using Taylor expansion method in SAS software, surveylogistic procedure. Training set (years 2000-2004) was utilized to develop the model and validation set (year 2005) was utilized to validate this model.
  
  
  RESULTS
  A total of 3,947 and 972 patients were included in training and validation sets, respectively. The overall actual-observed peri-operative mortality rates for training and validation sets were 4.1% and 3.2%, respectively. The decile-based calibration plots for the training set revealed good agreement between the observed probabilities and nomogram-predicted probabilities. Similarly, the quartile-based calibration plot for the validation set revealed good agreement between the observed and predicted probabilities. The accuracy of the nomogram was further reinforced by a good concordance index of 0.80 with a 95% confidence interval of 0.72 and 0.87.
  
  
  CONCLUSIONS
  This pre-operative nomogram may be utilized to predict the risk of peri-operative mortality following liver resection for malignancy.
authors.affiliation: Division of Surgical Oncology, Department of Surgery, University of Nebraska Medical Center, Eppley Cancer Center, Omaha, NE 68198, USA.
authors.forename: Mashaal
authors.initials: M
authors.lastname: Dhir
authors.forename: Lynette M
authors.initials: LM
authors.lastname: Smith
authors.forename: Fred
authors.initials: F
authors.lastname: Ullrich
authors.forename: Premila D
authors.initials: PD
authors.lastname: Leiphrakpam
authors.forename: Quan P
authors.initials: QP
authors.lastname: Ly
authors.forename: Aaron R
authors.initials: AR
authors.lastname: Sasson
authors.forename: Chandrakanth
authors.initials: C
authors.lastname: Are
mesh_terms: D000368:Aged; D005260:Female; D006498:Hepatectomy / Q000401:mortality*; D006801:Humans; D008113:Liver Neoplasms / Q000150:complications / Q000401:mortality* / Q000601:surgery*; D008297:Male; D015233:Models, Statistical; D049451:Nomograms; D018570:Risk Assessment
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