Effect of the lung allocation score on lung transplantation in the United States

Abstract

Background: On May 4, 2005, the system for allocation of deceased donor lungs for transplant in the United States changed from allocation based on waiting time to allocation based on the lung allocation score (LAS). We sought to determine the effect of the LAS on lung transplantation in the United States.

Methods: Organ Procurement and Transplantation Network data on listed and transplanted patients were analyzed for 5 calendar years before implementation of the LAS (2000-2004), and compared with data from 6 calendar years after implementation (2006-2011). Counts were compared between eras using the Wilcoxon rank sum test. The rates of transplant increase within each era were compared using an F-test. Survival rates computed using the Kaplan-Meier method were compared using the log-rank test.

Results: After introduction of the LAS, waitlist deaths decreased significantly, from 500/year to 300/year; the number of lung transplants increased, with double the annual increase in rate of lung transplants, despite no increase in donors; the distribution of recipient diagnoses changed dramatically, with significantly more patients with fibrotic lung disease receiving transplants; age of recipients increased significantly; and 1-year survival had a small but significant increase.

Conclusions: Allocating lungs for transplant based on urgency and benefit instead of waiting time was associated with fewer waitlist deaths, more transplants performed, and a change in distribution of recipient diagnoses to patients more likely to die on the waiting list.

Keywords: lung allocation score; lung transplant; organ allocation; transplant benefit; transplant urgency.