title: Does it matter what a hospital is "high volume" for? Specificity of hospital volume-outcome associations for surgical procedures: analysis of administrative data.
abstract: OBJECTIVE
  To determine whether the improved outcome of a surgical procedure in high volume hospitals is specific to the volume of the same procedure.
  
  
  METHODS
  Analysis of secondary data in Ontario, Canada.
  
  
  METHODS
  Patients having an oesophagectomy, colorectal resection for cancer, pancreaticoduodenectomy, major lung resection for cancer, or repair of an unruptured abdominal aortic aneurysm between 1994 and 1999.
  
  
  METHODS
  Odds ratio for death within 30 days of surgery in relation to the hospital volume of the same surgical procedure and the hospital volume of the other four procedures. Estimates were adjusted for age, sex, and comorbidity and accounted for hospital level clustering.
  
  
  RESULTS
  With the exception of colorectal resection, 30 day mortality seemed to be inversely related not only to the hospital volume of the same procedure but also to the hospital volume of most of the other procedures. In some cases the effect of the volume of a different procedure was stronger than the effect of the volume of the same procedure. For example, the association of mortality from pancreaticoduodenectomy with hospital volume of lung resection (odds ratio for death in hospitals with a high volume of lung resection compared with low volume 0.36, 95% confidence interval 0.23 to 0.57) was much stronger than the association of mortality from pancreaticoduodenectomy with hospital volume of pancreaticoduodenectomy (0.76, 0.44 to 1.32).
  
  
  CONCLUSIONS
  The inverse association between high volume of procedure and risk of operative death is not specific to the volume of the procedure being studied.
authors.affiliation: Department of Surgery, University of Toronto, 200 Elizabeth Street, 9EN-236A, Toronto, ON M5G 2C4, Canada. david.urbach@uhn.on.ca
authors.forename: David R
authors.initials: DR
authors.lastname: Urbach
authors.forename: Nancy N
authors.initials: NN
authors.lastname: Baxter
mesh_terms: D005260:Female; D006276:Health Facility Size; D006302:Health Services Research; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D009864:Ontario / Q000453:epidemiology; D012307:Risk Factors; D013503:Surgery Department, Hospital / Q000706:statistics & numerical data*; D013514:Surgical Procedures, Operative / Q000401:mortality* / Q000706:statistics & numerical data*; D016896:Treatment Outcome; D014600:Utilization Review