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 <= 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 (>= 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. (Ann Thorac Surg 2009;88:1062-70) (C) 2009 by The Society of Thoracic Surgeons