title: Low volume is associated with worse patient outcomes for pediatric liver transplant centers.
abstract: BACKGROUND
  An inverse association between hospital procedure volume and postoperative mortality has been demonstrated for a variety of pediatric surgical procedures. The objective of our study was to determine whether such an association exists for pediatric liver transplantation.
  
  
  METHODS
  We performed a retrospective analysis of pediatric liver transplant procedures included in the Scientific Registry of Transplant Recipients over a 7.5-year time period from July 1, 2000, through December 31, 2007. Pediatric liver transplant centers were divided into three volume categories (high, middle, low) based on absolute annual volume. Mean 1-year patient survival rates and aggregate 1-year observed-to-expected (O:E) patient death ratios were calculated for each hospital volume category and then compared using ordered logistic regression and chi square analyses.
  
  
  RESULTS
  High-volume pediatric liver transplant centers achieved significantly lower aggregate 1-year O:E patient death ratios than low-volume centers. When freestanding children's hospitals (FCH), children's hospitals within adult hospitals (CAH), and other centers (OC) were considered separately, we found that a significant volume-outcomes association existed among OC centers but not among FCH or CAH centers. Low-volume OC centers, which represent 41.6% of all pediatric liver transplant centers and perform 10% of all pediatric liver transplantation, had the least favorable aggregate 1-year O:E patient death ratio of all groups.
  
  
  CONCLUSIONS
  We demonstrate that a significant center volume-outcomes relationship exists among OC pediatric liver transplant centers but not among FCH or CAH centers. These findings support the possible institution of minimum annual procedure volume requirements for OC pediatric liver transplant centers.
authors.affiliation: Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Elisabeth T
authors.initials: ET
authors.lastname: Tracy
authors.forename: Kyla M
authors.initials: KM
authors.lastname: Bennett
authors.forename: Melissa E
authors.initials: ME
authors.lastname: Danko
authors.forename: Diana L
authors.initials: DL
authors.lastname: Diesen
authors.forename: Tammy J
authors.initials: TJ
authors.lastname: Westmoreland
authors.forename: Paul C
authors.initials: PC
authors.lastname: Kuo
authors.forename: Theodore N
authors.initials: TN
authors.lastname: Pappas
authors.forename: Henry E
authors.initials: HE
authors.lastname: Rice
authors.forename: John E
authors.initials: JE
authors.lastname: Scarborough
mesh_terms: D000328:Adult; D000367:Age Factors; D000554:Ambulatory Care Facilities / Q000706:statistics & numerical data; D002648:Child; D006776:Hospitals, Pediatric / Q000706:statistics & numerical data*; D006782:Hospitals, Special / Q000706:statistics & numerical data; D006801:Humans; D016031:Liver Transplantation / Q000401:mortality / Q000706:statistics & numerical data*; D008137:Longitudinal Studies; D017063:Outcome Assessment, Health Care; D011183:Postoperative Complications / Q000401:mortality; D016016:Proportional Hazards Models; D012042:Registries / Q000706:statistics & numerical data; D012189:Retrospective Studies; D015996:Survival Rate; D014180:Transplantation / Q000145:classification / Q000401:mortality / Q000706:statistics & numerical data*; D014481:United States