title: A preoperative nomogram to predict the risk of perioperative mortality following gastric resections for malignancy.
abstract: BACKGROUND
  Surgery remains one of the major treatment options available to patients with gastric cancer. The aim of this study was to develop a preoperative nomogram based on the presence of comorbidities to predict the risk of perioperative mortality following gastric resections for malignancy.
  
  
  METHODS
  The Nationwide Inpatient Sample (NIS) database was used to create a nomogram using SAS software. The training set (years 1993, 1996-97, 1999-2000, 2002, 2004-05) was used to develop the model which was further validated using the validation set (years 1994-95, 1998, 2001, and 2003).
  
  
  RESULTS
  A total of 14,235 and 9,404 patients were included in the training and validation sets, respectively, with overall actual observed perioperative mortality rates of 5.9 % and 6.6 %, respectively. The decile-based calibration plots for the training and validation sets revealed a good agreement between the observed and nomogram-predicted probabilities. The accuracy of the nomogram was further reinforced by a concordance index of 0.75 (95 % confidence interval 0.73 to 0.77) which was calculated using the validation set.
  
  
  CONCLUSIONS
  This preoperative nomogram may accurately predict the risk of perioperative mortality following gastric resections for malignancy and may be used as an adjunctive clinical tool in the preoperative counseling of these patients.
authors.affiliation: Department of Surgery, Division of Surgical Oncology, Eppley Cancer Center, University of Nebraska Medical Center, Omaha, NE, 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: D000293:Adolescent; D000328:Adult; D000368:Aged; D015897:Comorbidity; D005743:Gastrectomy / Q000401:mortality*; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D049451:Nomograms; D057234:Preoperative Period; D018570:Risk Assessment; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000401:mortality / Q000601:surgery*; D055815:Young Adult