Lung allocation score for lung transplantation - Impact on disease severity and survival

Background: Prior to implementation of the lung allocation score (LAS) system, allocation of donor lungs was based on accrued time on the waiting list and was potentially influenced by center-specific thresholds for listing. The impact of LAS implementation on patient characteristics and survival is unknown. Methods: United Network of Organ Sharing data were obtained on all lung transplant candidates listed and all patients undergoing transplantation in region 6 between May 4, 2003, and May 4, 2006. Each data set was divided into two cohorts: 2 years before LAS implementation, and 1 year after LAS implementation. LAS was calculated and compared by cohort. Pre-LAS and post-LAS differences in patient characteristics were examined. Waiting list and posttransplant survival rates for each cohort were examined using Kaplan-Meier estimates and Cox regression. Results: After LAS implementation, the distribution of diagnoses in patients undergoing transplantation significantly changed (p = 0.02), while the distribution of diagnoses in those listed did not (p = 0.17). Characteristics of patients on the waiting list were similar, except that a higher proportion of nonwhite patients were listed (p = 0.04) and lower FVC (p < 0.001) was observed after LAS implementation. Similarly, characteristics of patients undergoing transplantation did not change, except that posttransplant hospital length of stay was shorter (p = 0.01) after LAS implementation. Calculated LAS was higher after LAS implementation (p = 0.006). After controlling for age and diagnosis, neither waiting list nor transplant survival was significantly different (p = 0.93 and p = 0.81, respectively). Conclusions: After LAS implementation, the distribution of diagnoses in lung transplant recipients was significantly changed, while that of candidates was not. Posttransplant and waiting list survival were not affected by the LAS system, but power was limited. Larger and long-term survival studies are needed to determine if the LAS system improves over-all allocation and survival for patients interested in lung transplantation.