title: Hospital esophageal cancer resection volume does not predict patient mortality risk.
abstract: BACKGROUND
  Insurers often seek to direct esophageal cancer patients to hospitals with high volumes of esophageal resection. However, controversy exists regarding the strength and validity of evidence for the volume-outcome association. The purpose of this study was to evaluate the volume-outcome relationship for esophageal cancer resection in a large population dataset and to compare 3alternative techniques for measuring the effect of volume.
  
  
  METHODS
  Esophageal cancer resection patients were identified in the 2007 Nationwide Inpatient Sample. Hospital volume was measured using a continuous linear function, a nonlinear function using restricted cubic splines, and using quintiles of volume. The statistical significance of the relationship between hospital volume and mortality risk was assessed, and adjusted for patient age, for comorbid disease, and for correlated events within hospitals.
  
  
  RESULTS
  A total of 6,248 esophageal cancer resection patients from 217 hospitals were identified. All 3 models demonstrated excellent performance characteristics (C index=0.94, Nagelkerke R2=0.62). However, no significant association was demonstrated between hospital procedure volume and in-hospital mortality in any model. Important predictors of mortality included age, hypertension, weight loss, and peripheral vascular disease (p<0.001).
  
  
  CONCLUSIONS
  Esophageal cancer resection volume is not a significant predictor of mortality and should not be used as a proxy measure for surgical quality.
authors.affiliation: Department of Surgery, University of Virginia Health System, Charlottesville, Virginia; Department of Public Health Sciences, University of Virginia Health System, Charlottesville, Virginia, USA. bdk8g@virginia.edu
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Kozower
authors.forename: George J
authors.initials: GJ
authors.lastname: Stukenborg
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002423:Cause of Death; D016001:Confidence Intervals; D016208:Databases, Factual; D004938:Esophageal Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D016629:Esophagectomy / Q000379:methods / Q000401:mortality* / Q000706:statistics & numerical data; D005260:Female; D017052:Hospital Mortality / Q000639:trends*; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D007297:Inpatients / Q000706:statistics & numerical data; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016017:Odds Ratio; D017063:Outcome Assessment, Health Care; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D016019:Survival Analysis; D016896:Treatment Outcome; D016526:Workload / Q000706:statistics & numerical data*