title: Systematic review and meta-analysis of the volume-outcome relationship in pancreatic surgery.
abstract: BACKGROUND
  Many studies have shown lower mortality and higher survival rates after pancreatic surgery with high-volume providers, suggesting that centralization of pancreatic surgery can improve outcomes. The methodological quality of these studies is open to question. This study involves a systematic review of the volume-outcome relationship for pancreatic surgery with a meta-analysis of studies considered to be of good quality.
  
  
  METHODS
  A systematic search of electronic databases up to February 2010 was performed to identify all primary studies examining the effects of hospital or surgeon volume on postoperative mortality and survival after pancreatic surgery. All articles were critically appraised with regard to methodological quality and risk of bias. After strict inclusion, meta-analysis assuming a random-effects model was done to estimate the effect of higher surgeon or hospital volume on patient outcome.
  
  
  RESULTS
  Fourteen studies were included in the meta-analysis. The results showed a significant association between hospital volume and postoperative mortality (odds ratio 0.32, 95 per cent confidence interval 0.16 to 0.64), and between hospital volume and survival (hazard ratio 0.79, 0.70 to 0.89).The effect of surgeon volume on postoperative mortality was not significant (odds ratio 0.46, 0.17 to 1.26). Significant heterogeneity was seen in the analysis of hospital volume and mortality. Sensitivity analysis showed no correlation with the extent of risk adjustment or study country; after removing one outlier study, the result was homogeneous. The data did not suggest publication bias.
  
  
  CONCLUSIONS
  There was a consistent association between high hospital volume and lower postoperative mortality rates with improved long-term survival.
authors.affiliation: Department of Surgery, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: G A
authors.initials: GA
authors.lastname: Gooiker
authors.forename: W
authors.initials: W
authors.lastname: van Gijn
authors.forename: M W J M
authors.initials: MW
authors.lastname: Wouters
authors.forename: P N
authors.initials: PN
authors.lastname: Post
authors.forename: C J H
authors.initials: CJ
authors.lastname: van de Velde
authors.forename: R A E M
authors.initials: RA
authors.lastname: Tollenaar
mesh_terms: D003107:Colorectal Surgery / Q000706:statistics & numerical data*; D006276:Health Facility Size / Q000706:statistics & numerical data*; D006801:Humans; D010179:Pancreas / Q000601:surgery*; D010182:Pancreatic Diseases / Q000401:mortality / Q000601:surgery*; D011183:Postoperative Complications / Q000401:mortality*; D016896:Treatment Outcome; D016526:Workload / Q000706:statistics & numerical data*