title: The impact of center volume on survival in lung transplantation: an analysis of more than 10,000 cases.
abstract: BACKGROUND
  Whether center volume influences outcomes in lung transplantation is unknown. We reviewed United Network for Organ Sharing data to examine the effect of center volume on short-term mortality.
  
  
  METHODS
  We reviewed United Network for Organ Sharing data (1998 through 2007) to identify 10,496 first-time adult lung transplantation recipients at 79 centers. Centers were stratified by quartiles of mean annual volume. Risk of 30-day mortality and 1- and 5-year mortality (censored for 30-day death) were assessed by multivariable Cox proportional hazards regression.
  
  
  RESULTS
  Mean center volume ranged from less than 1 to 58.2 (median, 9.4 cases/year; volume quartiles: 0 to 2.1, 2.2 to 9.4, 9.5 to 19.9, and 20 to 58.2 cases). Each 1 case/year decrease led to a 2% increase in 30-day mortality (hazard ratio, 1.02; 95% confidence interval, 1.01 to 1.02; p < 0.001). Centers of lowest quartile (performing <or=2.1 lung transplantations/year) had a 30-day cumulative mortality of 9.6% or 89% increase in the risk of death (hazard ratio, 1.89; 95% confidence interval, 1.01 to 3.44; p = 0.05) compared with the highest quartile centers despite fewer idiopathic pulmonary fibrosis patients (15.6% versus 25.8%; p < 0.001) and younger age (40.9 versus 51.5 years; p < 0.001). Low-volume centers had double the risk of 30-day censored 1-year mortality (hazard ratio, 1.95; 95% confidence interval, 1.30 to 2.92; p = 0.001). High-volume centers (>or=20 lung transplantations/year) had the lowest 30-day mortality (4.1%).
  
  
  CONCLUSIONS
  We provide an initial examination of the relationship of volume and lung allocation score to outcomes for lung transplantation. Low center volume is associated with increased short-term and cumulative mortality despite fewer idiopathic pulmonary fibrosis patients and younger patients.
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, USA.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Weiss
authors.forename: Jeremiah G
authors.initials: JG
authors.lastname: Allen
authors.forename: Robert A
authors.initials: RA
authors.lastname: Meguid
authors.forename: Nishant D
authors.initials: ND
authors.lastname: Patel
authors.forename: Christian A
authors.initials: CA
authors.lastname: Merlo
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: Orens
authors.forename: William A
authors.initials: WA
authors.lastname: Baumgartner
authors.forename: John V
authors.initials: JV
authors.lastname: Conte
authors.forename: Ashish S
authors.initials: AS
authors.lastname: Shah
mesh_terms: D000328:Adult; D000368:Aged; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality / Q000639:trends; D006767:Hospitals, District / Q000706:statistics & numerical data*; D006801:Humans; D016040:Lung Transplantation / Q000401:mortality* / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012042:Registries; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology