The impact of center volume on survival in lung transplantation: an analysis of more than 10,000 cases.
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.
Weiss
Eric S
ES
Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, USA.
Allen
Jeremiah G
JG
Meguid
Robert A
RA
Patel
Nishant D
ND
Merlo
Christian A
CA
Orens
Jonathan B
JB
Baumgartner
William A
WA
Conte
John V
JV
Shah
Ashish S
AS
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